| P
| [1] Phosphorus An element with the atomic number of 15 [2] The designation for the park position of an automatic transmission. |
| P & G check
| The measurement of an engine's specifications, such as displacement, to determine the legality of competition using instruments provided by the P & G Management Company which allow such checks without the disassembly of the engine. |
| P-Channel
| A field effect transistor so constructed that p-type semiconductor material is used for the channel through the device. |
| P-metric system
| The most common system to specify passenger car tire sizes. |
| P-type semiconductor material (P)
| A semiconductor material in which holes are the majority carriers and there is a deficiency of electrons. |
| P/B
| Power brakes |
| P/C
| Printed circuit or police car |
| P/CV
| Ported/canister valve |
| P/N
| Park neutral |
| P/S
| Power steering or power seat |
| P/V
| Power vent |
| P/W
| Power window |
| PA
| [1] Pulse air; a type of air injection system [2] Protactinium An element with the atomic number of 91 |
| pace car
| A vehicle used in closed-course racing, usually a convertible passenger car, to lead the field up to speed for a rolling start. Also used to lead the field when a caution flag is displayed. |
| pace lap
| The last lap just before the start of a closed-course race, as the pace car leads the field up to speed. |
| pacer
| A driver that runs at the constant or steady speed in oval-track racing. |
| package
| A combination of optional equipment or accessories offered for a new car buyer usually discounted when compared to individual component pricing. |
| package tray
| The shelf behind the rear seat in a sedan. Early trunk-mounted air conditioners used ducts through the package tray as the intake and outlets of the unit. |
| pad
| A brake lining and metal back riveted or molded together. Two pads provide stopping friction by rubbing against both sides of a rotor or inside drum when the brakes are applied. |
| pad hardware
| Miscellaneous small parts such as antirattle clips and springs as well as support clips that hold brake pads in place and keep them from rattling. |
| pad-wear indicator
| A mechanical or electrical warning device on disc brakes that indicates need for pad replacement. |
| paddock area
| A designated area behind or near the pit where race cars are tuned and prepared for qualifying and racing. |
| PAF
| Pulse air feeder |
| PAFS
| Pulse air feeder system |
| PAFT
| An acronym for Program for Alternative Fluorocarbon Toxicity Testing. |
| PAG
| An acronym for poly alkaline glycol. |
| paint
| A material, generally containing binders, solvents, and pigments, that is applied as a liquid to a surface, and forms a solid film for decoration and/or protection. |
| paint shop
| The area in a repair facility where the vehicle is refinished by refinishing technicians or painters. |
| Paint, Body and Equipment Association (PBEA)
| A trade association of manufacturers, wholesalers, and distributors of vehicle paint and body-shop equipment. |
| PAIR
| Pulsed air injection reaction |
| PAIS
| Pulsed air injection system |
| pal nut
| A thin pressed-steel nut used to lock a regular nut place. |
| pallet
| A special platform, usually wooden, used to support and transport, usually by fork lift, components in the shop, or for storage between manufacture and assembly. |
| pan
| A term often used for oil pan. |
| pan rails
| The sides of an oil pan that bolt to the engine block. |
| pancake engine
| An engine having opposed pistons, such as a flat four, or a flat six. |
| panel beater
| A body shop worker. |
| panel cutter
| Special "snips" used to cut through body sheet metal, designed to leave a clean, straight edge that can be easily welded. |
| panel nut
| A thin nut used to hold parts or fittings to a firewall or bulkhead. |
| panel truck
| An enclosed light truck or van having no windows in the cargo area. |
| panhard rod
| A rod that is attached to the vehicle frame at one end and to the axle at the other end to prevent the chassis from moving side to side relative to the axle; used on a beam axle or de Dion axle type rear suspension. |
| paper
| Sheets of fibrous absorbent materials made from organic fibers that will "swallow up" liquids and may well disintegrate under such action if the liquid is a solvent for the binder. |
| parabolic reflector
| A reflector in the shape of a concave parabola used for radar and other microwave antennas. |
| parade lap
| A lap or laps in closed-course racing before the pace lap to give the drivers an opportunity to warm up their tires and engines and to give the fans a chance for a good look at the cars at a slow speed. |
| parallel circuit
| An electric circuit having two or more paths that the current flows through at the same time. The current is divided with more of it flowing through the path of least resistance. |
| parallel linkage
| A steering linkage having equal-length tie rods. |
| parallel-joint type
| A drive shaft installation whereby all companion flanges and/or yokes in the drive line are parallel with each other with the working angles of the joints of a given shaft being equal and opposite. |
| parallel-series circuit
| A circuit with several parallel branches, each branch containing one or more series components. |
| parallelogram linkage
| A steering linkage system having a short idler arm mounted on the right side in such a manner that is parallel to the pitman arm. |
| parameter
| A particular measured value that characterizes the behavior of an electronic unit or device. |
| parasitic drag
| Any interference of the aerodynamic efficiency of a vehicle body such as may be caused by outside mirrors, door handles, antenna, and windshield wiper arms and blades. |
| parasitic load
| An electrical load that is present when the ignition switch is in the OFF position. |
| parent metal
| The original metal in a body panel to which another metal panel has been added. |
| parity
| An error-checking scheme whereby additional bits are added to data to aid in detecting common errors in data transmissions. |
| park contacts
| Electrical contacts, inside a windshield-wiper motor assembly, to provide current to the motor after the control switch has been turned to the OFF or PARK position, allowing continued motor operation until reaching the park position. |
| Park Neutral Switch
| Used on vvehiclesequipped with automatic transmissions to indicate the transmissions shifted postion |
| parking brake control
| The pedal of lever used to apply the parking brakes. |
| parking-brake cable
| A cable or cables that transmit brake-actuating force in the parking-brake system. |
| parking-brake equalizer
| A device used to equalize the pull between the parking brake actuator and two rear wheels. |
| parking-brake system
| A brake system, intended to hold a vehicle stationary, in which one or more brakes may be held in the applied position without continued application of force to the control. |
| part number (PN)
| The alphanumeric designating a part as listed in a catalog or parts list. |
| part out
| To sell an assembly, such as an engine, piece by piece. |
| particle
| A very small piece of dirt, metal or other debris which can be contained in oil, air, or fuel that can be removed with a filter. |
| particulate
| 1. A solid matter, mainly soot from burned carbon, in an internal combustion engine's exhaust. 2. A form of solid air pollution such as microscopic solid or liquid matter that floats in the air. |
| particulate emissions
| Solid particles, such as carbon and lead, found in vehicle exhaust soot. A problem, especially in diesels. |
| particulate trap
| An emissions control device in the exhaust system of a diesel engine which is used to capture particulate before they can enter the atmosphere. |
| parting edge
| The excess flash material that is found around the edge of a part that has been cast in a two-piece mold. |
| partition coefficient
| The ratio of the solubility of a chemical in water as compared to its solubility in oil. |
| partitions
| Separations between the cells of a battery. |
| parts changer
| One who, without proper diagnostic skills, randomly changes parts until the remedy to a problem is found. |
| parts chaser
| 1. A vehicle used for errands. 2. A person who runs errands, especially for buying parts. |
| parts counterman
| One very knowledgeable in part numbers, and/or determining requirements who generally works in a parts-supply wholesale ore retail outlet. |
| parts distribution
| A wholesale, discount, or retail establishment that sells parts to the trade or do-it-yourselfer. |
| parts manager
| One responsible for ensuring that the in-house stock of parts is adequate so the customer's parts are readily available to the service technician when needed. |
| parts per million (ppm)
| 1. A unit used to measure the amount of contamination in a substance, such as moisture in refrigerant. 2. A measurement of the emissions of a motor vehicle given as the number of parts of a particular chemical within one million parts of exhaust gas. |
| parts requisition
| A form that is used to order parts. |
| parts specialist
| One who sells automotive engine and vehicle parts. |
| parts washer
| A machine that is used to clean parts. |
| PAS
| Pulse air system |
| PAS-ABV
| Pulse air system-anti-backfire valve |
| PAS-ACOV
| Pulse air system-air cut-off valve |
| PAS-ACS
| Pulse air system-air control solenoid |
| PAS-ACV
| Pulse air system-air control valve |
| PAS-AIV
| Pulse air system-air injection valve |
| PAS-ASCS
| Pulse air system-air suction control solenoid |
| PAS-ASOV
| Pulse air system-air shut-off valve |
| PAS-ASS
| Pulse air system-air switching solenoid |
| PAS-ASV
| Pulse air system-air switching valve |
| PAS-AVCS
| Pulse air system-air valve control solenoid |
| PAS-CSV
| Pulse air system-control solenoid valve |
| PAS-DV
| Pulse air system-diverter valve |
| PAS-PAF
| Pulse air system-pulse air feeder |
| PAS-PAV
| Pulse air system-pulse air valve |
| PAS-RV
| Pulse air system-reed valve |
| PAS-SCSV
| Pulse air system-swirl control solenoid valve |
| PAS-SCV
| Pulse air system-swirl control valve |
| PAS-VSV
| Pulse air system-vacuum switching valve |
| pass
| To run down a drag strip. |
| passages
| A term often used for coolant passages or water jacket. |
| passenger car
| A four-wheeled, motor-driven vehicle that carries ten passengers or less, intended for used on streets and highways. |
| passive
| 1. Receiving or subjected to an action without responding or initiating a corresponding action. 2. Accepting without resistance or objection. |
| passive diagnostic test
| The vehicle computer monitors all vehicle system, circuit, or component, looking for values of voltage that fall out of a predetermined range. |
| passive restraint
| Occupant restraints, such as air bags or seat belts, that operate automatically with no action required on the part of the driver or occupant, as mandated by Federal regulations to be used in all vehicles sold in the United States after 1990. |
| Passive Restraints
| A passenger restraint (seat belt) system that automatically operates to confine the movement of a vehicle's passengers |
| passive seal
| A seal that has no extra springs or tension devices to help make the seal, such as the O-ring seals on valves. |
| Passive test
| A diagnostic test in which the control module monitors a component or system during normal operation |
| pasting
| The process of applying active battery material onto the grid framework of each plate. |
| patch
| 1. The area of contact of a tire with the road surface when the tire is supporting the weight of the vehicle. 2. A small, rubber-like piece of material for repairing a puncture in an inner tube. 3. A term often used for a temporary repair. |
| patch area
| A term used for tire contact area. |
| PAV
| Pulse air valve |
| PAVC/DS
| Pulse air control valve/down stream |
| PAVC/US
| Pulse air control valve/up stream |
| PAW
| An acronym for plasma arc welding. |
| pawl
| 1. A ratchet tooth that is used to lock a device. 2. A hinged or pivoted component that engages a toothed wheel or rod to provide rotation or movement in one direction while preventing movement in the opposite direction |
| payload
| The weight of the cargo that may be carried by a truck, determined by subtracting the curb weight of the vehicle and 150 pounds (68 kg) for each passenger from the gross vehicle-weight rating. |
| Pb
| Lead An element with the atomic number of 82 |
| PBEA
| An acronym for Paint, Body and Equipment Association. |
| PbO2
| Lead dioxide |
| PbSO4
| Lead sulfate |
| PC seals
| Valve stem seals made by Perfect Circle that have Teflon inserts to wipe the stems clean. |
| PCI Bus
| Various modules exchange information through a communications port called the programmable communications interface (pci) Bus |
| PCM
| Powertrain control module |
| PCS
| Purge control solenoid |
| PCSDM
| Passenger compartment sensor/diagnostic module |
| PCSV
| Purge control solenoid valve |
| PCV
| An acronym for positive crankcase ventilation. |
| PCV hose
| A Neoprene-or synthetic-rubber hose that is connected to one or both ends of a PCV valve. |
| PCV valve
| A vacuum-controlled metering device that regulates the flow of crankcase ventilation system by allowing more flow at high speed than at low speed, and acts as a system shutoff in case of engine backfire to prevent an explosion in the crankcase. |
| PCV-DOV
| Positive crankcase ventilation-dual orifice valve |
| PCV-HCB
| Positive crankcase ventilation-heated crankcase breather |
| PCVV
| Positive crankcase vent valve |
| Pd
| Palladium An element with the atomic number of 46 |
| PDAS
| (Porsche) Porsche Dynamic All Wheel Drive Control System |
| PDI
| An acronym for predelivery inspection. |
| peak
| Maximum, as in peak horsepower, meaning maximum horsepower. |
| Peak and hold
| Full current applied to an injector to rase the pintle, then reduced to hold the pintle up for the remainder of the pulse width |
| Peak Detection
| An acquisition mode available with digital oscilloscopes that enables you to observe signal details that may otherwise be missed |
| peak inverse voltage (PIV)
| The maximum reverse voltage which a semiconductor junction can withstand without permanently damaging the junction |
| peak out
| The engine speed at which maximum horsepower is developed. |
| Peak-inverse voltage
| also called peak-reverse voltage This is the rating of a diode that indicates the maximum amount of voltage in the reverse direction that can be applied to the device with out dammage. |
| peak-to-peak amplitude
| The signal amplitude measured between the maximum positive and negative peaks excursions of an ac signal. |
| Peak-to-peak Voltageg
| The voltage measured from the maximum point of a signal to its minimum point |
| peaked
| A body panel having raised beading for a styling effect. |
| Peal-and-hold injector
| A peak-and-hold injector is typically used for TBI and some port low-resistance injector systems. |
| pearlescent paint
| A color paint with fine mica particles blended into the pigment. |
| pedal clearance
| The amount of downward brake-pedal movement, 1/4 inch (6.35 mm) or so, before the pushrod contacts the piston. |
| pedal to the metal
| The accelerator pedal pressed all the way to the floor. |
| PEDES
| Pressure operated-elect divert and elect-switching |
| peel
| To leave streaks of rubber on the pavement during hard acceleration. |
| peel rubber
| A term used for lay rubber; the same as to peel. |
| peel test
| A destructive method of testing that mechanically separates a lap joint by peeling it. |
| peen
| 1. To shape metal by pounding it. 2. The ball-shaped end of a hammer head. |
| peg
| 1. A pin at the top end of a speedometer or tachometer to prevent instrument damage. 2. The highest possible reading on a speedometer. |
| PEL
| An acronym for permissible exposure limit. |
| pellet thermostat
| An engine-coolant thermostat having a wax pellet as a power element, which grows when heated and shrinks when cooled, connected through a piston to a valve. |
| pellet-bed catalytic converter
| A General Motors catalytic converter design having a stainless steel shell and a bed of catalyst-coated ceramic pellets that can be replaced using special vibrator/aspirator equipment. |
| pen
| To draw or design. |
| penetrating oil
| A special, thin oil that penetrates rust and/or tight threads and helps in the removal of stubborn nuts and bolts. |
| Pentroof Combustion Chamber
| A flat or pancake shaped combustion chamber that has the overhead valve heads that are almost parallel to the top of the pistion and the spark plug at or near the center of the chamber. This design provides a very short distance for the flame front to travel, excellent air flow characteristics and efficient combustion. |
| PERA
| An acronym for Production Engine Remanufactures Association. |
| percent
| The ratio of one material to another in a mixture as in a fuel mixture. |
| percent of grade
| A value that is determined by dividing the height of a hill by its length, often used to determine the power requirements of trucks or for determining maximum pay load. |
| percolation
| A condition in which the fuel-bowl vent fails to open when the engine is turned off and internal pressure forces raw fuel through the main jets into the manifold. |
| performance chart
| A chart that has been produced from a dynamometer showing the horsepower, torque, and fuel consumption of an engine at various speeds. |
| performance test
| 1. Readings of the temperature and pressure, under controlled conditions, to determine if an air-conditioning system is operating at full efficiency. 2. A test to determine if a system or sub-system is performing at maximum efficiency. |
| perimeter frame
| A conventional chassis frame design that is similar in construction to a ladder frame, having full-length side rails that support the body at its greatest width, providing optimum protection to passengers in the event of a side impact. |
| period
| The length of time required for one cycle of a periodic wave. |
| peripheral device
| Any external device attached to a computer; examples of peripherals include printers, disk drives, keyboards monitors and scantools |
| Permaloy
| A permanent-magnet allow of Nickel and Iron. |
| permanent magnet
| A piece of ferrous material, such as steel, that retains its magnetic properties without the use on an electric current. |
| Permanent magnet generator
| A reluctance sensor. A sensor that generates a voltage signal by moving a conductor through a permeant magnetic field. |
| permanent strainer
| A device generally of a Y-configuration having an accessible cylindrical strainer element used in horizontal and vertical lines. The element, retained by a plug end which may be plain or fitted with a valve, can be opened for "blow-through" cleaning. |
| Permatex
| A tradename for a brand of engine and transmission sealants. |
| permeability
| The measure of the ease with which magnetic lines of force can move through a material compared with air. |
| Permissible exposure limit (PEL)
| The maximum length of time a person should be exposed to a hazard or hazardous material established by OSHA and expressed as a time-weighted average limit or ceiling exposure limit. |
| peta
| The prefix representing the number 1,000,000,000,000,000 |
| petcock
| A small faucet-like valve used for draining liquids, such as that found at the bottom of some radiators. |
| Petrol
| English term for Gasoline |
| petroleum
| The crude oil from which gasoline, lubricant, and other such products are manufactured. |
| PEVR
| Power enrichment vacuum regulator |
| PFE
| Pressure feedback EGR |
| PFI
| Port fuel injection |
| PFI-MA
| Ported fuel injection-mass airflow |
| PG
| See Propylene Glycol |
| PGM-FI
| Programmed Fuel Injected This is Honda's fuel injection system used on Accord, Civic, and Prelude modles |
| pH level
| A measure of the acidity or alkalinity of a solution on a scale where pH0 is most acid, pH14 is most alkaline, and pH7 is neutral. |
| phaeton
| A four or five passenger, two- or four-door, open-body style that was most popular in the 1920s and 1930s. |
| phase
| The time displacement expressed as an angular displacement between two or more ac quantities. |
| Phase Separation
| Happons when the alcohol in the gasoline absorbs water in the tank and sinks to the bottom |
| phase shift
| The time difference between two or more signals measured between reference points on each signal and usually expressed in angular displacement degrees. |
| phenolic plastic
| Plastic made primarily from phenol, a compound derived from benzene or carbolic acid. |
| phosgene gas
| A highly toxic gas, carbonyl chloride (CCOCI2). Until recently, it was believed that phosgene gas was produced when CFC refrigerants, such as R-12, came into contact with heated metal or an open flame. It is now known that little or none of this gas is produced in this manner. |
| phosphor bronze
| A hard, tough alloy of copper (Cu), lead (Pb), tin (Sn), and phosphorus (P) low in friction and resistant to wear. |
| phosphoric acid
| A colorless and odorless acid (H3PO4) used to remove rust from steel and cast iron. |
| photochemical smog
| A noxious, unhealthy gaseous compound in the atmosphere, formed by the interaction of various chemicals such as the pollutants hydrocarbons (HC) and oxides of nitrogen (NOx) in the presence of sunlight. |
| photodiode
| A semiconductor diode operated as a photo conductor. Normal operation is with its junction reverse biased. |
| photoelectric principle
| The production of electricity created by light striking certain sensitive materials, such as selenium or cesium. |
| photon
| A single quantum of light energy that moves as a unit at the speed of light. |
| phototransistor
| A bipolar transistor that has gain and produces collector current when light shines on its collector-base junction. |
| photovoltaic diode
| A device having a junction of two dissimilar metals that produces an electrical signal proportional to the amount of light that strikes it. |
| physical hazards
| Any personal hazards, such as excessive noise, temperature, pressure, and rotating equipment. |
| physical properties
| Properties that pertain tot he physics of a material, such as melting point, density, electrical and thermal conductivity, specific heat, and coefficient of thermal expansion. |
| Pi
| The mathematical constant which is equal to the ratio of the circumference of a circle to its diameter. Approximately 3.1415927 |
| pickup
| 1. Vehicle acceleration. 2. A term used for pickup truck. |
| pickup coil
| An engine-speed sensor in an electronic engine system. |
| pickup truck
| A type of vehicle having an open cargo bed behind an enclosed cab. |
| pickup tube
| 1. A tube extending from the outlet of the receiver almost to the bottom of the tank to ensure that 100% liquid is supplied to the liquid line or metering device. 2. A tube used to transfer fuel or oil from the storage tank. |
| pico
| The prefix representing the number. 0.000,000,000,001 |
| PID
| An acronym for Parameter Identification Data; The opperating parameters of a sensor or device |
| piece work
| A method of payment whereby a worker receives an agreed fixed amount per piece produced. |
| piezoelectric
| A crystal property which causes a voltage to be developed across the crystal when mechanical stress is applied |
| Piezoelectricity
| Voltage produced by the application of pressure or vibration to certain crystals |
| piezoresistive
| A sensor whose resistance varies in relation to pressure or force applied to it. A piezoresistive sensor receives a constant reference voltage and returns a variable signal in relation to its varying resistance. |
| Piezoresistive Sensor
| A sensor (knock) that is sensitive to pressure changes or viborations |
| pig
| 1. An unattractive vehicle. 2. A vehicle that is not performing well or as expected. 3. A bar of cast metal. |
| Pig tale
| [1] A wiring component such as a bulb socker that is provided with wires attached for connecting to the original vehicle wiring. [2] A wiring repair connection some times refereed to as a western union pig tale splice |
| pigment
| Small particles added to the paint to influence properties such as color, corrosion resistance, and mechanical strength. |
| Pikes Peak
| A 14,110 foot (4,300 meters) high mountain peak in central Colorado where an annual auto-racing hill climb is held around the Fourth of July. |
| pilot
| 1. A driver. 2. A device that guides the operation of a machine or part. |
| pilot bearing
| The bearing at the output end of the engine's crankshaft that supports the transmissions input shaft. |
| pilot hole
| A small hole drilled into a part to serve as a guide for a larger sized drill bit. |
| pilot model
| The first vehicle of a new design to be constructed on the assembly line to test the assembly procedures and fixtures before full-scale production begins. |
| pilot operated
| A small valve used to energize or regulate a large valve. |
| pilot shaft
| A shaft that is used to align parts during assembly. |
| pilot-operated absolute (POA)
| A term used for pilot-operated evaporator pressure regulator. |
| pilot-operated evaporator pressure regulator (POEPR)
| An evaporator pressure regulated valve that is regulated by an internal pilot-valve pressure. |
| PIN
| [1] An acronym for product identification number. [2] A threaded tapered metal part used to repair cracks in castings such as an engine block using a process called pinning |
| ping
| A mild knock noise from the engine. |
| pinion
| 1. A small gear such as at the end of the steering shaft of a rack-and-pinion steering system. 2. A small ring gear such as the planet gears in a planetary gear set. 3. The small gear on the end of a starter drive which rotates the engine flywheel ring gear for starting. |
| pinion bearing
| A bearing that is used to support the pinion gear in the differential housing. |
| Pinion Factor
| A calculation using the final drive ratio and the tire circumference to obtain accurate vehicle speed signals |
| pinion gears
| A term used for pinion. |
| pinion seal
| An oil seal for the pinion gear in a ring and pinion. |
| pinion shaft
| A shaft used to support a pinion bearing and/or pinion. |
| pink slip
| A vehicle ownership certificate. |
| pinning
| Using a series of pins to repair and crack in the casting by screwing them into a series of predrilled holes in a manner so that they overlap each other from one end of the crack to the other. |
| pintle
| A valve-like part of a fuel injector that controls the fuel-spray pattern. |
| pintle hook
| A pin installed in the rear of some vehicles for attaching a tow bar. |
| pintle valve
| The ball and seat found inside a thermostatic expansion valve, attached to the diaphragm, which causes it to open and close in response to pressure changes. |
| PIP
| Profile injection pick-up |
| pipe
| An exhaust system. |
| pipe brace
| A brace that extends between opposite hangers on a spring or air-type suspension. |
| pipe dream
| An illusionary fantasy plan, or way of life. |
| pipes
| A dual-exhaust system. |
| piston
| 1. An engine part that reciprocates in the cylinder and transfers the force of the expanding gases via the piston pin and connecting rod to the crankshaft. 2. A round, caliper component in a disc brake that is moved outward by fluid pressure to press the pads against each rotor face. 3. An aluminum or sintered-iron component of a drum brake inside a wheel cylinder that supports the cylinder cup. 4. That part of a compressor that is driven by a crankshaft to compress vapor. 5. A small cylinder fitted inside a hollow cylinder which moves back and forth by fluid pressure to transmit reciprocating motion inside the transmission. |
| piston boss
| That part of the piston which supports the piston pin. |
| piston bushing
| a bushing that is pressed into the upper end of the connecting rod when free-floating pins are used. |
| piston crown
| The top of the piston. |
| piston displacement
| The cylinder volume displacement by the piston as it travels from the bottom to the top of the cylinder during one complete stroke. |
| piston markings
| Marks on a piston which are used to identify piston oversize and the front of the piston. |
| piston material
| metal used in piston construction, usually cast- or forged-alloy aluminum. |
| piston oil ring
| A term used for oil ring. |
| piston oil squirt hole
| A term used for oil squirt hole. |
| piston oiler
| A device that injects oil into the piston as an aid to carry away heat from the piston crown. |
| piston pin
| A round precision-ground part usually hollow, used to attach the piston to the connecting rod by press fit or held in place with internal snap rings. |
| piston rings
| Rings that fit into grooves on the outer wall of a piston, just below the crown, that seal the combustion chambers and scrape oil from the cylinder walls. |
| piston rod
| A plated rod attached tot he shock-absorber piston, usually extending to the top of the shock to provide attachment to the vehicle. |
| piston skirt
| The lower part of the piston that makes contact with the cylinder wall. |
| piston slap
| The noise that is made by an undersize or loose piston skirt as it makes contact with the cylinder wall. |
| piston speed
| The velocity of a piston, given in feet per minute, as it reciprocates in a cylinder. |
| piston stops
| The tabs, or protrusions, on a backing plate so positioned as to prevent the wheel cylinder pistons from leaving the wheel cylinder. |
| piston temperature
| The temperature of the piston at different areas, varying from over 450?F (232?C) at the crown, to 200?F (93?C) near the bottom of the skirt. |
| piston valve
| A shock-absorber component used to control the flow of oil and produce the pressure and vacuum in the chamber above the piston during compression and rebound. |
| piston-ring land
| The surface of a piston between ring grooves. |
| piston-rod seal
| A non-replaceable oil seal around a movable piston rod, located at the upper end of the hydraulic cylinder. |
| piston-skirt clearance
| The allowable space between the piston skirt and cylinder wall, usually 0.001 to 0.002 inch (about 0.025 to 0.051 mm) at room temperature. |
| piston-skirt expander
| A device that may be inserted behind the piston skirt to force the skirt out toward the cylinder wall to reduce skirt-to-wall clearance. |
| piston-to-valve clearance
| The distance between the intake and exhaust valves and the piston crown when the valves are at overlap period and the piston is at top dead center. |
| pit crew
| 1. Those responsible for servicing, timing, and the communications of a race car during a race on the track side of the pit wall. 2. Those who support the team efforts on the infield side of the pit wall. |
| pit stop
| A visit to the pits during a race for routine or emergency service or to ask directions. |
| pit wall
| A wall that divides the pit service facilities on the trackside and infield side. |
| pitch
| 1. The rotating motion of a vehicle's spring mass about its lateral axis, compressing the springs at one end of the vehicle and extending the springs at the other end. 2. The uniform spacing of adjacent elements of a series of points, lines, joints, planes, blades, or teeth, as in a broach or gear. 3. The center-to-center dimension between chain joints. 4. For in a sprocket, the dimension between the centers of rollers bedded against the bottoms of adjacent tooth spaces. 5. The distance between corresponding points on adjacent threads. 6. The angle of a setting of some tools. 7. The distance from center-to-center of wire in adjacent coils in an open-wound spring. |
| pitman arm
| Arm attached to the pitman shaft that moves the relay rod as the steering wheel is turned. |
| pits
| The trackside service facilities for servicing vehicles competing in a race. |
| pitting
| Metal-surface irregularities as a result of corrosion. |
| PIV
| Peak inverse voltage |
| pivot
| A pin or short shaft upon which another part rests or turns, or about which another part rotates or oscillates. |
| pivot bushing
| A rubber bushing in the front suspension located at the inner end of the control arms where pivoting occurs. |
| pizza cutters
| The extremely narrow front wheels of a drag-race car used to reduce rolling resistance. |
| pk
| Pink. |
| placard
| 1. A notice for display in a public (obvious) place. 2. A label or poster. |
| plain ends
| End coils of a helical spring having a constant pitch and with the ends not squared. |
| plain vanilla
| 1. Ordinary and without frills. 2. A low-priced economy car. |
| planet carrier
| The cradle that holds the planet gears in a planetary gear set. |
| planet pinions
| Small gears that orbit around the sun gear, meshing with and rotating between the sun and internal gears. |
| planetary carrier
| The framework holding the planetary pinions within the sun gear. |
| planetary gear set
| A group of gears named after the solar system because of their arrangement and action. This unit consists of a center (sun) gear around which the pinion (planet) gears revolve. The assembly is placed inside a ring gear having internal teeth. All gears mesh constantly. Planetary gear sets may be used to increase or decrease torque and/or obtain neutral, low, intermediate, high, or reverse. |
| planetary gear system
| A gear set consisting of a central sun gear surrounded by two or more planet gears which are, in turn, meshed with a ring gear, used in overdrives and automatic transmissions. |
| planetary gear train
| Gears of the transmission in either the Simpson or Ravigneaux design. |
| planetary pinion gears
| Small gears fitted into a framework called the planetary carrier. |
| planing
| A condition that exists when a tire is unable to stay in contact with the ground or pavement due to water. Also known as hydroplaning or aquaplaning. |
| plant it
| To apply full throttle. |
| plasma
| An inert gas used in welding, such as argon or nitrogen. |
| plasma arc welding (PAW)
| An arc welding process that uses a constricted arc between a non-consumable electrode and the weld pool (transferred arc) or between the electrode and the constricting nozzle (non-transferred arc) with shielding obtained from the ionized gas issuing from the torch, which may be supplemented by an auxiliary source of shielding gas. |
| plastic deformation
| A micro-structural change as a result of exceeding the yield point of the material and generally including elongation of the grain structure and increased hardness. |
| plastic filler
| A two-part, putty-like material that may be used to fill dents in body panels. |
| plastic gasket compound
| A plastic paste that is squeezed out of a tube to make a gasket in any shape or configuration. |
| plastic spring
| A term used for fiber-composite spring. |
| Plastigauge
| The tradename for a small, thin, plastic strip that is used to help determine the clearance between main and/or connection rod bearings and the crankshaft journals. |
| plate
| 1. A rectangular sheet of spongy lead in a battery. 2. A platform on which an assembly may be mounted. |
| plate group
| All of the positive plates and all of the negative plates that make up one battery cell. |
| platform
| The basic understructure of a vehicle including all running gear. |
| platinum (Pt)
| A rare, valuable metallic element which is highly resistant to corrosion, and is used as a catalytic agent in automotive catalytic converters of the oxidizing type. |
| plenum
| 1. A chamber containing air under pressure. 2. A chamber containing a gas such as air or an air/fuel mixture under higher than atmospheric pressure. |
| plenum chamber
| An area, filled with air at a pressure that is slightly higher than the surrounding air pressure, such as the chamber just before the blower motor. |
| plenum-blower assembly
| Located on the engine side of the firewall, this assembly contains air ducts, air valves, and a blower that permits the selection or air from the outside or inside of the car and directs it to the evaporator or to the heater core if desired. |
| Plexiglas
| A brand name of a transparent, lightweight plastic material often used for windows in an enclosed race car. |
| plies
| The cord plies that surround both beads and extend around the inner surface of the tire to enable the tire to carry its load. |
| plow
| A condition in cornering when the slip angles of the front tires are greater than the slip angles of the rear tires and the front end tends to break loose and slide. |
| plug
| 1. A spark plug. 2. A threaded, tapered metal pin used to repair cracks in castings, such as an engine block. |
| plug weld
| A weld made in a circular hole in one member of a joint, fusing that member to another member. |
| plunger
| That part of a hydraulic valve lifter that moves up or down depending on oil pressure. |
| ply rating (PR)
| A method used to indicate relative tire strength, formerly used to designate the load-carrying capacity of a tire. The ply rating does not necessarily indicate the actual number of plies: a four-ply rated tire, for example, may have two plies but is considered as strong as a standard four-ply tire. |
| Pm
| [1] Promethium An element with the atomic number of 61 [2] An acronym for preventative maintenance [3] An acronym for permanent magnet |
| PM 10
| Particulate mater with an areodynamic diameter of 10 microns |
| PM 2.5
| Particulate Matter with an aerodynamic diameter of 2.5 microns |
| PM generator
| A reluctance sensor. A sensor that generates a voltage signal by moving a conductor through a permeant magnetic field. |
| PM motor
| a permanent-magnet electric motor. |
| PM-10
| Particulate matter smaller than 10 microns |
| PMA
| An acronym for Professional Mechanics Association. |
| PN
| An acronym for part number. |
| PN diode
| A semiconductor diode formed by a p-n junction |
| PN Junction
| The point at which two opposite semiconductor materials are joined togather |
| Pneumatic tools
| Power tools that are powered by compressed air |
| PNP
| Transistor with N-type base |
| Po
| Polonium An element with the atomic number of 84 |
| POA
| An acronym for pilot-operated absolute, as in a suction throttling valve. |
| POA valve
| A term used for suction throttling valve. |
| POASTV
| An acronym for pilot-operated absolute suction throttling valve. |
| POE
| An acronym for the synthetic lubricant polyol ester. |
| POEPR
| An acronym for pilot-operated evaporator pressure regulator. |
| pogo stick
| The air- and electrical-line support rod mounted behind the cap to keep the lines from dragging between the tractor and trailer. |
| point of intersection
| Apex of the extended centerline of the pivot axis and the extended centerline of a front wheel. |
| points
| A term used for breaker points. |
| polar moment of inertia
| 1. The tendency of a body to resist angular or rotational acceleration. 2. The tendency of a vehicle to resist cornering. |
| polarity
| 1.The quality of an electrical circuit or component that determines the direction of current flow. 2. The description of wether a voltage is positive or negative with respect to some reference point. 3. The condition of being positive or negative in relation to a magnetic pole. |
| polarizing a generator
| The correction of the generator-field polarity so it will build up polarity in the proper direction to charge the battery. |
| pole
| The starting position on the inside of the front row in oval-track or road racing. |
| poles
| A positive ( or negative ) terminal in a cell or battery; the ends of a magnet ( north or south). |
| police options
| The high-performance equipment package available on new cars for law enforcement authorities. |
| police package
| A term used for police options. |
| polished
| Intake and exhaust passages that have been finished to the smoothest possible surfaces to remove the rough surfaces left by factory casting. |
| pollutant
| 1. Any substance that adds to the pollution of the atmosphere. 2. Any substance in the exhaust gas from an engine or evaporating from the fuel tank or carburetor. |
| pollution
| 1. Any gas or substance in the air that makes the air less fit to breathe. 2. Excessive noise from machinery or vehicles. |
| poly alkaline glycol (PAG)
| The synthetic lubricant of choice in many automotive air conditioners used with HFC-134a refrigerant. |
| poly ester
| A synthetic lubricant that is used in some HFC-134a air-conditioning systems. |
| poly lock
| A type of rocker-arm lock nut that is secured with a set screw. |
| polyglycol
| A mixture of several alcohols. Polyalkylene-glycol-ether brake fluids that meet specifications for DOT 3 and 4 brake fluids. |
| polymer
| A substance made of giant molecules formed from smaller molecules of the same substance. |
| polymerization
| A chemical reaction whereby many small molecules combine to form larger, more complex molecules having a higher molecular weight with different chemical properties. |
| polyurethane
| A synthetic material often used as a filter media. |
| poncho
| A Pontiac. |
| ponies
| Horsepower. |
| pony car
| Any compact, two-door sports car similar to a Mustang. |
| Pooch
| A Porsche. |
| pop
| A racing fuel, generally with nitromethane. |
| pop back
| A condition when the air/fuel mixture is ignited in the intake manifold and may cause a "pop back" through the carburetor. |
| pop rivet
| A fastener used to hold two pieces together. |
| pop the clutch
| To engage the clutch suddenly. |
| pop-off valve
| A spring-loaded pressure relief valve. |
| pop-up menu
| A list of choisces displayed as an addition to the regular menu |
| poppet valve
| 1. A valve that plugs and unplugs its opening by axial motion 2. An intake or exhaust valve consisting of a disc at the end of a shaft used in a four-stroke cycle engine. |
| porcelain
| A hard, ceramic material as used in spark plugs to insulate the electrode from the shell. |
| porcupine head
| The cylinder head on a rat motor. |
| port
| A term used for intake port or exhaust port. |
| port bowl
| The area of the port next to the valve head. |
| port injection
| A fuel injection system that injects fuel directly into the individual intake ports. |
| port runner
| A partition in the intake manifold that directs the air/fuel mixture to the individual cylinders. |
| portable cable
| An electrical cable used to transmit electrical power to the mobile equipment. |
| ported vacuum
| Engine vacuum, available above the throttle plates of a carburetor, used to advance ignition timing when the throttle is opened above its idle position. |
| ported-vacuum switch (PVS)
| A valve which permits or stops the passage of a ported vacuum to a vacuum-operated component, such as a distributor advance mechanism that may be thermostatically operated, or controlled by electric current or the movement of a mechanical component. |
| porting
| To enlarge the intake and exhaust passages. |
| Pos-A-Traction
| A brand of tires, tubes and wheels. |
| posi
| A generic term for a limited-slip differential. |
| Posi-Traction
| A limited-slip differential by Chevrolet. |
| position sensor
| A termed used for EGR valve-position sensor. |
| positioned weld
| A weld made in a joint that has been placed in a position to facilitate making the weld. |
| positive
| 1. One of the two poles of a magnet. 2. One of the two terminals of an electrical device, such as a battery. 3 A pressure greater than atmospheric. |
| positive absolute-suction throttling valve
| A suction throttling valve having bronze bellows under a nearly perfect vacuum, which is not affected by atmospheric pressure. |
| positive back-pressure EGR valve
| A common type of exhaust gas recirculation valve which uses exhaust system backpressure to sense engine load, thus more accurately metering the amount of exhaust recycled. |
| positive camber
| The outward tilt of a wheel on a vehicle. |
| positive crankcase ventilation (PCV)
| An engine emissions-control system, operating on engine vacuum, that picks up crankcase gases and meters them into the intake stream to be burned. |
| positive displacement pump
| An engine driven air or liquid pump that displaces the same amount of air or liquid, per revolution, regardless of engine speed. |
| Positive engagement starter
| A Ford type of starter motor that uses the magneticfield strength of a field winding to engage the starter drive into the flywheel ring-gear |
| positive offset
| A wheel rim placed outward of the center of the mounting flange. |
| positive pole
| 1. The positive terminal of an electrical device. 2. The north pole of a magnet. |
| positive post
| the positive terminal of a battery. |
| Positive Temperature Coefficient Device
| An electrical component in which the resistance increases as the temperature surrounding it increases |
| positive terminal
| The terminal to which electrons flow in a complete electrical circuit often identified by the symbol +. |
| positive traction
| A limited-slip differential by Buick. |
| positive wheel slip
| The excessive wheel spin that occurs during acceleration as a wheel loses traction and spins on the pavement. |
| positive wiping seal
| A seal that maintains constant contact with a stem or shaft to wipe off excess oil. |
| post
| A battery terminal. |
| post ignition
| Ignition that occurs after the engine-ignition system is shut off, due to carbon buildup in the combustion chamber. |
| post start
| The time from a cold start to the warm up of an engine. |
| Postcombustion Emissions Device
| A device such as the catalitic converter that controls emissions after the combustion event |
| pot
| 1. A carburetor. 2. An acronym for potentiometer. |
| Potassium Hydroxide
| 1. A solution of the elements potassium, hydrogen, and oxygen that serves as the electrolyte for a type of fuel cell. Chemically KOH. |
| Potential
| The ability to do somthing |
| potential difference
| The voltage difference between two points, calculated algebraically. |
| potential energy
| Energy of a body or system with respect to the position of the body or the arrangement of the particles of the system. |
| potentiometer (pot)
| A three-wire variable resistor that acts as a voltage divider to produce a continuously variable output signal proportional to a mechanical position. |
| pounds per horsepower
| The weight of the vehicle divided by its horsepower, a measure of the vehicle's performance. |
| pounds per square inch (psi)
| An English measure for pressure or stress. |
| pounds per square inch, absolute (psia)
| An English measure for pressure or stress taken from absolute pressure. |
| pounds per square inch, gauge (psig)
| An English measure for pressure or stress taken from atmospheric pressure. |
| pounds-feet
| An English measure of torque. One pound (lb) raised on foot (ft) is equal to one pounds-feet (lb-ft). |
| pounds-inch
| An English measure of torque; the energy required to raise one pound, one inch. |
| pour on the coal
| To accelerate rapidly. |
| pour point
| The lowest temperature at which a fluid will flow freely. |
| poured bearings
| Bearings that are formed by first pouring molten babbitt material into the bearing cavity, allowing tit to cool, then boring it to a specific size. |
| powder puff race
| An auto-racing event strictly for women drivers. |
| power
| 1. A measure of work being done. 2. The rate at which work is being done. In mechanics, power is measured as torque times speed and expressed in units such as horsepower or watts. |
| power brakes
| A system utilizing energy from the vehicle's engine to reduce the amount of brake-pedal pressure that must be exerted by the driver to stop the car. |
| power break
| In an automatic transmission-equipped drag racer, the act of holding the brake pedal firmly while revving the engine, the simultaneously releasing the brake while flooring the accelerator to get the quickest possible start. |
| power cable
| Cable used to supply electrical power (current). |
| power control module
| A module or computer used in an electronic transmission to aid in control of the shift solenoids. |
| power cylinder
| 1. A shell containing the power-brake operating parts. 2. Linkage-type steering component attached between the frame and the steering relay rod. |
| power flow
| The flow of power from the input shaft through one or more sets of gears, or through an automatic transmission to the output shaft. |
| Power Formula
| A formula used to calculate the amount of electrical power a component uses. The formula is P = I x E, whereas P stands for Power in Watts, I stands for Current, and E stands for Voltage |
| power hop
| The tendency of an axle housing to rotate slightly with the wheels then snap back during hard acceleration. |
| power mirror
| Outside mirrors, having reversible permanent-magnet motors, that are electrically positioned from the inside of the driver's compartment. |
| power on/off watchdog circuit
| Supplies a reset voltage to the microprocessor in the event that pulsating output signals from the microprocessor are interrupted. |
| power oversteer
| The loss of traction of the rear wheels while cornering and accelerating, causing the rear of the vehicle to swing toward the outside of the turn. |
| power piston
| A component acted on by pressurized fluid to assist wheel turning on integral or linkage-type power-steering systems. |
| power plant
| An engine. |
| power section
| The section of a gas-turbine engine containing the power turbine rotors which, through reduction gears, turn the wheels of the vehicle. |
| power servo
| A servo unit used in automatic temperature control which is operated by a vacuum or an electric signal. |
| power shift
| The rapid forced shifting of a manual transmission without releasing the clutch or accelerator. |
| power slide
| A controlled four-wheel skid in dirt-track racing to maintain speed through a turn. |
| power steering
| A power assisted steering system that uses hydraulic pressure to increase the torque (turning effort) applied to the steering wheel by the driver. |
| power steering analyzer
| A diagnostic device that tests flow, pressure, and operation of everything hydraulic in the power steering system. |
| power steering fluid
| Special hydraulic fluid formulated to withstand extremely high system pressures and temperatures. |
| power steering pump
| A hydraulic pump driven by a belt from a crankshaft pulley to provide up to 1,300 psi (8,964kPa) "boost" pressure necessary to operate the power-steering system. |
| power steering, integral-type
| A power-steering system having the power assist mechanism and related controls inside the steering gearbox. |
| power steering, linkage-type
| A power-steering system having the control valve and power cylinder attached to the steering linkage under the car. |
| power stroke
| The piston stroke, with both valves closed, in which combustion takes place, forcing the piston from TDC to BDC. |
| power supply
| A defined unit that is the source of electrical power for a device, circuit, subsystem or system. |
| power synchronizer
| A device in the transmission that speed us the rotation of the main0section gearing for smoother automatic downshifts and to slow down the rotation of the main-section gearing for smoother automatic upshifts. |
| power take off (PTO)
| An output shaft found on some four-wheel drive vehicles for driving an external accessory, such as a winch. |
| power team
| The engine, transmission, rear end, and axle combination. |
| power tools
| Tools that use compressed air (pneumatics), electricity, or hydraulic pressure to generate and multiply the force required to accomplish the work. |
| power valve
| A valve in the carburetor that opens during acceleration to increase fuel flow. |
| power-to-weight ratio
| The relationship of a vehicle's horsepower to its weight as given in horsepower per pound. |
| powermaster
| A self-contained hydraulic power braking system with its own hydraulic reservoir and independent electric pump developed by General Motors for cars and trucks that could not economically use vacuum-assisted power brakes. |
| powertrain
| All of the vehicles components that contribute to the generation, transmission, and distribution of drive torque to the wheels. |
| ppm
| An acronym for parts per million. |
| Pr
| Praseodymium An element with the atomic number of 59 |
| PR/RV
| Pressure relief/rollover valve |
| prang
| A collision of vehicles. |
| pre-alignment check
| A series of checks the technician must perform before an alignment can be done. All steering and suspension parts are checked for looseness, wear, damage, and general condition. |
| pre-cat converter
| A term used for light-off, mini-oxidation catalytic converter. |
| pre-ignition
| The ignition of the air/fuel mixture in the combustion chamber by means other than the spark, usually caused by hot spots in the combustion chamber due to sharp edges, carbon accumulation, or spark plugs with a heat range that is too hot. |
| Pre-trigger Viewing
| The ability of a digital oscilloscope to capture what a signal did befor a trigger event. |
| precision insert bearing
| Bearings that may be installed in an engine without having to be bored, reamed, honed, or ground. |
| precombustion chamber
| A second combustion chamber placed directly off the main combustion chamber, used to ignite a rich mixture of air and fuel which then ignites a lean mixture in the main combustion chamber. |
| Precombustion Emissions Device
| A device that controles emissions before the combustion event as with the O2 sensor |
| predelivery inspection (PDI)
| The process of inspecting, adjusting, and fine tuning a new car prior to delivery to the customer. |
| preformed radiator hose
| A large-diameter hose connecting the radiator to the engine cooling system that is molded in the proper shape to fit on a certain engine. |
| preheater
| A glow plug that is used to heat the precombustion chamber of a diesel engine before it is started. |
| preheating
| Heating the weld area of a metal before welding, to avoid thermal shock and stress. |
| preload
| 1. The transfer of weight from one side of the vehicle to the other to compensate for the lateral weight transfer that occurs when cornering. 2. The pressure applied to a part during assembly or installation. |
| preload spring
| A part in a clutch assembly that applies pressure to a clutch pack to help in the coupling action |
| prelube
| To apply lubricant to the parts of a rebuilt engine before starting it up. |
| prerun
| 1. To examine and appraise and off-road race route. 2. To test a rebuilt engine before installing it in the vehicle. |
| prerunner
| 1. A vehicle that is built to be used to examine and evaluate the off-road route of an upcoming race. 2. A vehicle often used as an off-road race-chase vehicle for parts, fuel, and other supplies. |
| press fit
| The fitting of two parts with very close tolerances, one inside the other, generally by using a hydraulic press. Also known as force fit. |
| pressure
| 1. Force applied to a specific area, force per unit area or fore divided by area, usually expressed in psi, psig, or psia (kPa or kPa absolute). |
| pressure balancing ring
| A compression ring having a ceramic coating to ensure sealing against the cylinder wall. |
| pressure bleeder
| A device used to facilitate the removal of air from the brake system. |
| pressure bleeding
| Bleeding the brake system using a pressure bleeder to charge the system. |
| pressure cap
| A cap placed on the radiator to increase the pressure of the cooling system, reduce cavitation, protect the radiator hoses, and prevent or reduce surging. |
| pressure connector
| A connector applied using pressure to form a cold weld between two parts. |
| pressure control valve
| A device used to control and regulate the pressure of a system or sub-system. |
| pressure differential
| The difference between two pressures or two surfaces or in two separate areas. The pressure can be either pneumatic ( air ) or hydraulic ( fluid ) |
| pressure differential valve
| A valve used in a dual-brake system to turn on a dash warning light if the pressure drops in either part of the system. |
| pressure drop
| The loss of pressure due to a restriction, a lone, line, or a small diameter line. |
| pressure hold
| One condition in an anti-lock brake control module in which no more braking pressure can be produced in the master cylinder. |
| pressure hose
| A special, reinforced high-pressure hose through which pressurized fluid flows. |
| pressure line
| 1. A term that generally refers to the discharge line of an air-conditioning system. 2. A term that may apply to brake or power-steering hoses. |
| pressure plate
| That part of a manual clutch that is mounted on and rotates with the flywheel and exerts pressure against the friction disk. |
| pressure plate assembly
| An assembly of various parts that operate to "press" the clutch disc against the flywheel, engaging power flow to the clutch shaft, or "release" the disc, disengaging power flow. |
| pressure reduction
| A drop of pressure due to a restriction or metering device. |
| pressure regulator
| 1. A device that operates to prevent excess pressure buildup in a system. 2. A valve in some automatic transmissions that opens to release oil from a line when the oil pressure reaches a specific maximum limit. |
| pressure release grill
| An air vent that prevents pressure from building up inside the car while the air-conditioning system is operating. |
| pressure relief groove
| A small groove cut in the piston-ring land between the grooves for the compression and oil rings to equalize combustion pressures between them. |
| pressure relief valve
| 1. A valve held closed by a spring or other means, which automatically relieves pressure in excess of its setting. 2. A carburetor fuel bowl vent operated by vapor pressure from evaporated fuel. 3. An air-injection system valve that functions to relieve pump-output pressure that exceeds a predetermined amount, usually at speeds over 45mph (72.4 km/hr). 4. A special valve in an engine lubricating system having a calibrated spring working against a moveable plunger or ball to regulate maximum oil pressure. |
| pressure switch
| An electrical switch that is actuated by a predetermined low or high pressure. |
| pressure test
| A procedure for testing the entire cooling system for leaks. |
| pressure tester
| A device used to pressure test the cooling system and pressure cap. |
| pressure-fed oil system
| A type of lubrication system that uses an oil pump to force oil to the various parts of an engine. |
| pressurize
| To apply more than atmospheric pressure to a device or system. |
| pressurized carburetor
| A carburetor on a turbocharged engine that mixes fuel with air under pressure from the turbo. |
| Pretensioner
| Used to tighten the seat belt and sholder harness around the occupant during an accident |
| prevailing torque nut
| A nut designed to develop an interference fit between the nut and bolt threads. |
| preventative maintenance (PM)
| A systematic and scheduled inspection and service of a vehicle to ensure proper maintenance to provide a standard for satisfactory and sound operational conditions. |
| price guides
| 1. A reference that is used to determine a proper fee for repair labor based on time. 2. A reference providing the value of used vehicles based on geographic location, condition, and accessories. |
| price leader
| A item that a merchant may sell at near or below cost to attract customers. |
| primary
| The low-voltage circuit of an ignition system. |
| primary air suspension system
| The term used for a type of vehicle system that uses air, instead of coil, leaf, or torsion bar type springs, to support the vehicles weight |
| primary brake shoe
| The brake shoe in a set which initiates self-energizing action. |
| primary circuit
| 1. The electrical circuit of the low-voltage winding of and ignition coil. 2. The main fuel passages in a carburetor. |
| primary damage
| The damage caused by the initial impact of a collision. |
| primary resistance
| A calibrated resistance wire or ballast resistor in a conventional ignition system inserted between the ignition switch and coil to reduce the primary voltage at low engine speeds. |
| primary seal
| A seal between the compressor shaft seal and the shaft to prevent the leakage of refrigerant and oil. |
| primary shoe
| The brake shoe toward the front of the vehicle in a dual-servo drum brake having a lining that may be shorter, thinner, and have different frictional characteristics from the second shoe. |
| primary surfacer
| A type of paint having a high-solids content which fills small imperfections in body wok and which usually must be sanded. |
| primary winding
| The outer, low-voltage winding of an ignition coil. |
| primer
| A type of paint applied to a surface to increase its compatibility with the topcoat or to improve the corrosion resistance of the substrate. |
| primer sealer
| A type of paint that provides adhesion for the topcoat and seals old, painted surfaces. |
| priming spring
| A coil spring that holds the movable slide in the maximum position in a vane-type pump. |
| prindle
| The standardized shift pattern for an automatic transmission, PRNDL. |
| printed circuit
| An electrical circuit made by applying a conductive material to a printed circuit board. |
| printed circuit board
| A thin, insulating board used to mount and connect various electronic components, such as resistors, diodes, switches, capacitors, and microchips in a pattern of conductive lines. |
| PRNDL
| Park Reverse Neutral Drive Low |
| pro stock
| A category for compact, passenger drag-racing cars with a big block V-8 engine having a maximum of 500 cubic inches (8.2 liters). |
| pro street
| A compact passenger car with a modified V-8 engine and rear drive built for street use. |
| probe
| A test lead used with electronic instruments to measure voltage, current, or resistance and to analyze circuits. |
| Processor
| The on-board computer that recieves data from sensors , processes it into output signals, that changes current engine condition twored idle engine condition |
| PROCO
| An acronym for programmed combustion. |
| product identification number (PIN)
| A four-digit code that is used to identify hazardous material during transportation. |
| production
| 1. A term used for stock. 2. A standard factory version. |
| Production Engine Remanufactures Association(PERA)
| A trade association of those who rebuild gasoline and diesel engines or manufacture and/or distribute engine parts and engine rebuilding equipment. |
| Professional Mechanics Association (PMA)
| An association of professional mechanics that offers members savings on tools, travel, insurance, training, equipment, and shoes. |
| profile
| A term used for aspect ration and tire profile. |
| program
| 1. The job instructions for a computer. 2. An organized list of instructions that, when executed, causes the computer to behave in a predetermined manner. Without programs computers are useless. |
| Program for Alternative Fluorocarbon Toxicity (PAFT) Testing
| A testing agency founded by refrigerant manufacturers for the purpose of study and testing of new refrigerants to determine toxicity levels. |
| Program for European Traffic with Highest Efficiency and Unprecedented Safety (Prometheus)
| A research and development effort by major European auto makers for the purpose of studying if telecommunications technology can improve the efficiency and safety of European roads. |
| programmable read-only memory (PROM)
| A read-only memory chip that can be programmed by electrical pulses to store the computer program and other data. |
| programmed combustion (PROCO)
| A research type of stratified charge engine developed by Ford. |
| programmed protection system
| A bypass valve system to protect the catalyst and their mainareas from being destroyed due to overheating conditions that may be caused by certain modes of operation or from an engine malfunction. |
| programmer
| The part os an automatic temperature control system that controls the blower speed, air mix doors, and vacuum diaphragms. |
| progressive linkage
| A carburetor linkage system used on multiple carburetors to progressively open the secondary circuits. |
| progressive-rate spring
| A spring used in a vehicle that stiffens under load. |
| PROM
| An acronym for programmable read-only memory. |
| Prometheus
| An acronym for Program for European Traffic with Highest Efficiency and Unprecedented Safety. |
| prony brake
| A machine for testing the power of an engine while running against a friction brake. |
| proof loading
| Subjecting chain to a tensile loading of some predetermined percentage of the chain's rating strength. |
| propane
| A combustible, liquefied petroleum gas (C3H8) that becomes a liquid when compressed. |
| propane enrichment
| A service procedure used to set idle mixture where a metered amount of propane gas is added to the intake stream and a resulting rpm increase is observed. |
| propeller shaft
| 1. A term used for drive shaft. 2. A hollow, steel shaft that connects the transmission output shaft to the differential drive pinion yoke through universal joints at each shaft end. |
| property class
| A number stamped on the end of a metric bolt to indicate the hardness of the bolt. |
| proportioning valve
| A valve in the brake hydraulic system that reduces pressure to the rear wheels to achieve better brake balance. |
| Propylene Glycol Antifreeze
| A Low-Tox antifreeze made form Propylene rather than Ethylene. While no antifreeze product is compleetly harmless, using propylene glycol antifreeze does provide an added margin of safety in the event of accidental ingestion. |
| protective atmosphere
| A gas or vacuum envelope surrounding the work pieces, used to prevent or reduce the formation of oxides and other detrimental surface substances, and to facilitate their removal. |
| protective tube
| A shock absorber component used to keep dirt and road dust away from the seals and piston rods. |
| protest
| 1. To object to a rule or conditions prior to the competition. 2. To accuse a competitor of a rules violation after a race competition. |
| proto
| An acronym for prototype. |
| protocol
| An agreed-upon format for transmitting data between two devices. |
| proton
| A positively-charged particle in the nucleus of an atom. With a mass about 1845 times larger than an electron, and a charge equal to it. |
| Proton Excange Membrane (PEM)
| 1. A polymer sheet that serves as the electrolyte in a type of fuel cell. |
| prototype (proto)
| 1. An individually built test version of a new design of a car or system. 2. An individually built vehicle in sports-car racing when an insufficient number of vehicles have been manufactured to be placed in a category. |
| prove-out circuit
| A function of the ignition switch that completes the warning light circuit to ground when it is in the START position, so the warning lights will be on during engine cranking to indicate to the driver that the bulbs are working properly. |
| proximity effect
| The distortion of current density due to magnetic fields increased by conductor diameter, close spacing, frequency, and magnetic materials such as steel conduit or beams. |
| Prussian blue
| A blue pigment in solution applied to the surface area used to determine the contact area between two mating surfaces. |
| PS
| Purge solenoid or position sensor |
| PSD
| (Porsche) Porsche Barrier Differential (928 Modles) |
| PSE
| An acronym for Pneumatic System Equipment |
| psi
| An acronym for pounds per square inch. |
| psia
| An acronym for pounds per square inch, absolute. |
| psig
| An acronym for pounds per square inch, gauge. |
| PSOM
| Programmable speedometer/odometer module |
| PSP
| Power steering pressure |
| PSPS
| Power steering pressure switch |
| psych
| To intimidate a competitor in competition. |
| Pt
| Platinum An element with the atomic number of 78 |
| PTC
| Positive Temperature Coefficient A type of thermistor in which resistance increases as temperature increases |
| PTO
| An acronym for power take off. |
| Pu
| Plutonium An element with the atomic number of 94 |
| public-domain software
| Refers to any program that is not copyrighted. Public-domain software is free and can be used without restrictions. |
| puck
| 1. A brake pad. 2. A valve-adjusting shim. |
| puffer
| A supercharger. |
| pull
| A condition whereby the vehicle veers to one side or the other when the brakes are applied. |
| pull circuit
| A circuit that brings a tractor cab from a fully tilted position up and over the center. |
| pull rod
| A body-working tool in which the curved end of the rod is inserted into the drilled hole to pull out dents. |
| pull up resistor
| A fixed resistor in a voltage divider circuit for sensor input signals. A variable resistor sensor changes its voltage drop proportionably to the quantity being measured, and the pullup resistor drops the rest or the reference voltage |
| pull-down menu
| A menu of commands or options that appears when you select an item with a mouse. |
| pull-in windings
| One of two electromagnetic windings inside a solenoid used to move the core. |
| pull-type clutch
| A type of clutch whereby the release bearing is pulled toward the transmission. |
| pulldown
| A term used for pumpdown. |
| pulley
| A wheel-shaped, belt-driven device used to drive engine accessories. |
| pulsation
| A surge that may be felt in the brake pedal during low-pressure braking. |
| Pulse
| A common waveform shape that has a fast rising edge, a width, and a fast falling edge |
| Pulse Air Injection Reaction System
| Pulse air directed in to the exhaust system to reduce exhaust emissions |
| pulse generators
| An electromagnetic unit that generates a voltage signal used to trigger the ignition control module that controls (turns on and off) the primary ignition current of the electronic ignition system. |
| Pulse Modulated
| A circuit that maintains average voltage levels by puulsing the voltage on and off. |
| pulse period
| A term used for pulse width. |
| Pulse Rate
| The number of pulses that take place over a spicific amount of time |
| pulse ring
| A ring on the crankshaft to trigger a sensor used with an onboard computer control ignition timing. |
| pulse time
| A term used for pulse width. |
| pulse train
| DC voltage that turns on and off in a series of pulses. |
| Pulse Trains
| A repetitive series of pulses |
| Pulse Width
| The amount of time the pulse take to go from low to high and back to low again, conventionally measured at 50% of full voltage |
| Pulse Width Modulation
| [1] A method of electronic control where the frequency of the pulses remains the same, but the percentage of "on time" compared to "Off time" varies [2] The characteristics of a continuous on-and-off cycling solenoid for a fixed number of times per second while the frequency of the cycles remains constant the ratio of on-time to off-time varies or is modulated |
| pulse-delay variable resistor
| A resistor in the electrical circuit of the wiper system used to delay the wiper motion from 0 to 25 seconds. |
| pulsed air system
| A shortened term for pulsed air-injection system. |
| pulsed air-injection system
| A device found in the exhaust emission system that injects pulses of ambient air into the exhaust as an aid in the burning of exhaust gases. |
| pump
| A device that transfers gas or liquid from one place to another and creates an increase in pressure or volume. |
| pump air bleed
| In a fuel-supply system, small vent holes in the mechanical fuel-pump body that allow air to enter and leave the pump as the diaphragm moves back and forth. |
| pump gas
| Standard gasoline without any additives. |
| pump impeller
| 1. That part of a fluid pump that causes the fluid to move. 2. The output drive member that receives its power from the engine. |
| pump link
| In a fuel-supply system, a short, connecting part between the pump rocker arm and the diaphragm on certain models. |
| pump reservoir
| A mainarea located on or adjacent to the pump, providing fluid and reserve for proper system operation. |
| pump rotors
| Parts of a positive displacement pump that uses rotating rotors to develop flow. |
| pump screen
| A filter to remove debris from a fluid before it enters the pump. |
| pump up
| A condition where a hydraulic-valve lifter has developed more pressure than required and prevents the valve from seating properly. |
| pumpdown
| A term used for evacuate, as in an air-conditioning system. Also known as pulldown. |
| pumping brakes
| A term that refers to the practice of depressing the brake pedal several times in quick succession. |
| punch
| A racing fuel, generally with nitromethane. |
| punch it
| 1. To apply full throttle. 2. A term used for plant it or punch off. |
| punch off
| A term used for punch it or plant it. |
| puncture-sealing tire
| A specialty tire made to permanently tread punctures up to 3/16 inch (4.76 mm) in diameter with a resultant rubber-compound sealer applied to the inside of the tire by the manufacturer. |
| pup converter
| A term used for light-off, mini-oxidation catalytic converter. |
| pur sang
| A french term for "pure blood" used to describe a particularly fine car. |
| pure stock
| A vehicle that conforms to all original factory specifications. |
| purge
| 1. To remove moisture and/or air from a system or a component by flushing with a dry gas, such as nitrogen (N). 2. To remove all refrigerant from an air-conditioning system. |
| purge valve
| A valve in some evaporative emission-control system charcoal canisters to limit the flow of vapor and air to the carburetor during idle. |
| purity test
| A static test that may be performed to compare a suspect refrigerant pressure to an appropriate temperature chart to determine its purity. |
| push
| A condition in cornering when the slip angle of the front tires is greater than the slip angle of the rear tires and the front end of the vehicle tends to break loose and slide toward the outside of the turn. |
| push angle
| 1. The travel angle when the electrode is pointing in the direction of weld progression. 2. Also used to partially define the position of guns, torches, rods, and beams. |
| push bar
| A bar in the front of the push car to prevent damage to either vehicle when push-starting a race car. |
| push car
| Usually a truck; a vehicle used to push start a race car. |
| push circuit
| A circuit that raises a tractor cab from the lowered position to the desired tilt position. |
| push start
| To start a vehicle by pushing it with another. |
| push-type clutch
| A type of clutch in which the release bearing is not attached to the clutch cover. |
| pusher
| A rear-engine vehicle. |
| pushrod
| 1. A solid or hollow rod which serves as a link between the valve lifter and rocker arm. 2. The rod that transmits the movement and force of the driver from the brake pedal lever to the master cylinder. 3. The rod that transmits the movement and force of the wheel cylinder piston to the brake shoe. |
| pushrod tube
| The passage from the engine block to the cylinder head that contains a pushrod. |
| pussycat
| A smooth, quiet running vehicle. |
| put on the trailer
| To decisively defeat a racing competitor. |
| put to the wood
| A term for applying full throttle. |
| putter
| A custom car that is not intended for high performance. |
| putty
| Body filler. |
| PVA
| Ported vacuum advance |
| PVCS
| Ported valve control system |
| PVCS-A
| Ported valve control system-actuator |
| PVCS-CS
| Ported valve control system-control solenoid |
| PVS
| An acronym for ported-vacuum switch. |
| PWM
| Pulse width modulation |
| PWM Diagnostic Protocol
| Pulse Width Modulation Diagnostic Protocol used by the Ford Motor Co. is considered a high speed communication at 41.6 Kb/s two wire |
| pyroconductivity
| Electric conductivity that develops with changing temperature, and notably upon fusion in solids that are practically nonconductive at atmospheric temperatures. |
| pyrolysis
| The decomposition of a compound due to its exposure to high heat. |
| pyrolytic oven
| An oven used to remove grease, oil, and rust from the surfaces of engine parts. |
| pyrometer
| An instrument used to measure high temperatures. |
| pyrophoric
| A substance having the quality of spontaneous ignition when exposed to air. |
Auto & Car Glossary
