| m
| Meter |
| M.H.
| Motor home |
| M/C
| Mixture control |
| M/C solenoid
| Mixture control solenoid. Used in conjunction with the Oxygen sensor on feedback carburetors to control the air fuel ratio. |
| M/D
| Medium duty |
| M/T
| Manual transmission |
| MA
| [1] An acronym for Mass air the amount of air entering the engine [2] An acronym for milliampere 1/1000 of an ampere |
| MA-PFI
| Mass air port fuel injection |
| MAC
| A tool manufacturer and supplier to the automotive industry |
| machinability
| The relative ease with which materials can be shaped by cutting, drilling, or other chip-forming processes. |
| machine
| 1. A car, usually a late-model car. 2. A device capable of doing work. |
| MacPherson strut
| A type of front suspension having a shock absorber mounted directly below the coil spring. |
| MacPherson strut rear suspension
| An independent, rear-suspension system having a shock-absorber strut assembly on each side, two parallel control arms, a tie rod, a strut rod, a forged spindle, a jounce bumper, and a bracket assembly. |
| MACS
| An acronym for Mobile Air Conditioning Society. |
| MAF
| Mass Air Flow |
| MAFS
| Mass Air Flow Sensor |
| mag
| 1. An acronym for magneto. 2. An acronym for magnesium. 3. A term used for a lightweight wheel, such as one made of aluminum or magnesium. |
| mag wheels
| 1. A magnesium wheel. 2. A term used to describe any chromed, aluminum offset, or wide-rim wheel of spoked design. |
| magnaflux
| A dry, nondestructive magnetic test to check for cracks or flaws in iron or steel parts. |
| Magnaglow
| A trade term for a wet, magnetic, and ultraviolet nondestructive test to check for cracks or flaws in iron or steel parts. |
| Magnequench
| A magnetic alloy made form neodymium, iron, and boron. Most commonly used in General Motors starting motors and alternators. |
| magnesium
| An element, Mg, that is the lightest weight of all structural materials. |
| magnet
| A piece or iron, steel. Or other magnetic substance which has been magnetized and has a magnetic field surrounding it. |
| magnetic clutch
| A coupling device used to turn the compressor on and off electrically. |
| magnetic field
| The area of influence of a permanent- or electro-magnet that exists between its north and south poles. |
| magnetic filter
| A magnet or magnet assembly located in a fluid system to attract and retain ferrous metal, nickel, and cobalt particles which may be present, composite particles in which a ferro-magnetic material is entrained may also be present. |
| magnetic lines of force
| The invisible magnetic lines set up between the north and south poles of a magnet. |
| magnetic particle test
| A non-destructive test using a magnet and magnetic particles, such as iron filings, to check iron or steel parts for cracks. |
| magnetic pick up
| The system of an electronic ignition that triggers the amplifier to generate voltage to fire the plugs. |
| magnetic pickup coil
| A small coil of wire would on an iron core in an electric ignition system that is magnetically affected as the reluctor teeth pass by. |
| magnetic poles
| The point at which the magnetic lines of force enter or leave a magnet. |
| magnetic switch
| A switch energized electrically with a coil of wire serving as an electromagnet, such as in a relay. |
| magnetic timing
| [1] A method of measuring ignition timing that uses a magnetic pick-up tool to sense the location of a magnet or slot on the harmonic balancer |
| magnetism
| The natural or electrical ability to attract a ferrous metal. |
| magneto
| An electrical device requiring no outside power source, that generates and delivers current to fire the spark plugs. |
| mags
| Wheels. |
| main
| 1. The main bearing. 2. The feature event. |
| main bearings
| The bearings that locate and support the crankshaft in an engine block. |
| main cap
| The structural device that holds the crankshaft in place in an engine block. |
| main hoop
| A rollbar placed just behind the driver's seat in a race car. |
| main jets
| The nozzle in a carburetor that provides fuel during part- or full-throttle operation. |
| main journals
| The journals that fit into the engine block to support the crankshaft. |
| main leaf
| Usually the top leaf on multiple-leaf springs that provides the main vehicle support and contains the spring-mounting "eyes." |
| main-body structural components
| The assembly made up of the dash panel, underbody, roof, body panels, doors, and deck lid to form the passenger and luggage compartments. |
| mainline pressure
| The pump-developed, hydraulic-regulated pressure that operates apply devices, such as bands, and is the source of all other pressures in an automatic transmission. |
| mains
| A term used for main bearings and main cap. |
| Maintenance Awareness Program (MAP)
| A coalition of automobile repair shops, suppliers, car companies, and associations dedicated to building trust between the aftermarket and its customers. |
| maintenance manual
| A manufacturer's or independent publication containing comprehensive maintenance information for a certain vehicle. |
| maintenance specifications
| A listing of interval oil and lube grades, service points, and capacities for periodic routine preventative maintenance service. |
| maintenance-free battery
| A sealed battery having no practical provision for the addition of water to the cells, since periodic maintenance is unnecessary. |
| MAIR
| Managed air injection reaction |
| major diameter
| 1. The largest in diameter of a cylinder. 2. The largest in the diameter of a bolt, its threads. |
| major overhaul
| An engine overhaul just short of a rebuild, where all worn or damaged parts are rebuilt or replaced. |
| major tune-up
| A conventional, ignition-engine maintenance procedure that may include points, capacitor cap, rotor, plugs, plug wires, valve adjustment, and a carburetor overhaul. |
| make
| 1. To close a switch. 2. A distinctive name given to a group of cars by a manufacturer, such as Riviera, by Buick. |
| make and break
| 1. The term used when a switch is closed or opened. 2. A pair of contact points, one stationary, and the other operated by a cam that makes the brake, such as in a conventional distributor. 3. To construct something then tear it down. |
| make the show
| To qualify for a race. |
| male
| A term universally applied to any part which fits into another part, such as the shaft on which a pulley or gear hub fits. |
| male and female
| Terms that apply to inner and outer members which fit together, such as a bolt and nut. |
| malfunction
| 1.An improper or incorrect operation of a device or system. 2. The failure to work or perform. |
| malfunction indicator lamp (MIL)
| This amber dashboard warning light may be labeled "check engine" or "service engine soon" |
| malleability
| The ability of a metal to be formed through hammering or bending. |
| manganese
| An element (Mn), used in alloys of iron, steel, aluminum, and copper, often confused with magnesium (Mg). |
| manganese bronze
| An alloy of copper, zinc, and up to 3.0% manganese used for toothed wheels and gears. |
| manganese steel
| A steel alloy with 12-14% manganese; used for drill bits |
| manifold
| 1. A device used to hold two or more gauges with fluid passages and flow provisions; used for testing ans servicing purposes. 2. A conduit-like device used to channel the air/fuel mixture into an engine. 3. A conduit-like device used to duct the exhaust gas out of an engine. |
| manifold absolute pressure (MAP)
| The pressure in an intake manifold relative to atmospheric pressure. |
| manifold absolute-pressure sensor
| A variable resistor used as a sensor to signal an engine-control computer relative to the vacuum conditions in the intake manifold. |
| manifold air temperature
| The temperature of the intake stream in the intake manifold, as increased by a heat riser or an Early Fuel-Evaporation system, and/or converted to an engine-control computer input by a sensor. |
| manifold gauge set
| 1. A set of gauges used to service an air-conditioning system. 2. A set of gauges used to measure vacuum or pressure in an engine's intake or exhaust system. |
| manifold heat control
| A flapper-type valve in the exhaust manifold that diverts heat to the intake manifold. |
| manifold pressure
| A positive pressure in the intake manifold measured in pounds per square inch or bars. |
| manifold vacuum
| The negative pressure in an engine's intake manifold produce by the engine's pumping action and measured in inches of mercury. |
| manomometer (u-tube)
| A u-shaped tube with a graduated scale used for measuring the pressure of gases or vapors. |
| manual bleeding
| A two-technician technique for bleeding brakes; one pumps the brakes as the other opens and closes the bleeder screws when required. |
| manual control valve
| A spool valve, located in the valve body, that determines fluid flow from the valve body to various hydraulic circuits controlled by the vehicle driver through the selector lever. |
| manual low
| The position of the units in an automatic transmission when the driver selects the Low or first-gear position of the quadrant. |
| manual operation
| 1. The act of operating the power steering system in the event of an engine system failure; increased effort is required. 2. The ability to override or cancel any automatic or semi-automatic function. |
| manual selection
| The vehicle operator's ability to 1. Move the gear selector lever by hand, such as with a manual transmission. 2. Select any condition or function using a keypad, switch or lever. |
| manual slide release
| The release mechanism for a sliding fifth wheel, which is operated by hand. |
| manual transmission
| A manually shifted gearing device in the power train that allows variation on the relationship between engine speed and road speed. |
| manufacturer
| A person, or corporation engaged in the mass production or assembly of vehicles or any other product. |
| manufacturer's code
| 1. An alpha-numeric code to identify a product. 2. A lettered marking code on tire sidewalls indicating tire manufacturer, plant, tire size, type of construction, and date of manufacture. |
| manufacturer's service manual
| A book containing service information and technical data that is provided by the vehicle manufacturer. |
| Manufacturers of Emission Controls Association (MECA)
| A trade association of the manufacturers of emission-control systems and components. |
| manufacturing
| The science of planning, designing, managing, and scheduling people, goods, material, equipment, and machinery to produce a useable and sellable product. |
| MAP
| [1] Manifold Absolute Pressure ie all pressures above below and at atmospheric found in the engines intake manifold [2] Following and plotting a circuit signal on an oscilloscope over a period of time |
| MAP sensor
| A device used to measure MAP. |
| MAPPA
| Manifold absolute pressure per altitude |
| marbles
| Small pieces of dirt, rubber, or other debris on the outer edges of the race track, outside the racing line. |
| marcel
| The spring assembly in the clutch-drive plate that absorbs the energy when the clutch lever is released. |
| margin
| The material between the face and head of an intake or exhaust valve. |
| Mark
| 1. One of the series of cars usually identified by a Roman numeral. 2. A term often mistakenly used for marque. |
| markings
| The identifying marks on an assembly or component. |
| marque
| A French term meaning "make," as in make of car. |
| marriage
| The installation of a vehicle's power train in its chassis on an assembly line. |
| MAS
| An acronym for mass airflow sensor. |
| masking
| 1. To cover up, as in prior to painting. 2. The modifying of intake ports with dams to redirect the air flow. |
| masking area
| A preparation stage in a paint shop in which the parts that are not to be painted are covered with paper and held in place with masking tape. |
| mass
| The measure of the quantity of matter that is contained in a given quantity of solid, liquid, or gas. |
| Mass Air Flow
| Measurement of the volume and density of the air entering the engine. |
| mass airflow sensor (MAS)
| A device found at the inlet of the intake manifold of an electronic fuel-injection system which supplies the computer with input as to the volume of air entering the manifold, using the temperature differential between a heated platinum wire or a plastic film and the passing air, to generate a signal of varying voltage. |
| mass production
| The manufacture of a product in large quantities. |
| master control
| A primary or main control. |
| master cylinder
| A brake-system component having an integral reservoir filled with hydraulic brake fluid where pressure is developed when the driver depresses the brake pedal causing a linkage to move a piston. |
| master kit (MK)
| An engine kit that contains crankshaft and camshaft bearings, lifters, oil pump, pistons, rings, gasket set, and core plugs. |
| master leaf
| A term used for main leaf, as in a spring. |
| Mastertech
| A Scantool manufactured by the Vetronix corporation. |
| MAT
| Manifold air temperature |
| mat fabric
| A fiberglass fabric with an irregular strand pattern. |
| match bash
| Two out of three, or three out of five drag racing events. |
| match race
| The same as match bash. |
| MATCO
| A tool manufacturer and supplier to the automotive industry |
| material expanders
| Fillers that are used in the place of active material in a battery; the primary difference between a 3- and 5-year battery. |
| Material Safety Data Sheet (MSDS)
| A sheet required of the product manufacturer by OSHA, containing specific information about hazardous materials to be displayed in any workplace where such materials are used. |
| matter
| 1. Anything that occupies space and possesses mass or weight 2. All things in nature are composed of matter. |
| maxi-fuse
| A large, cartridge-type fuse having a higher current-capacity use because they are less likely to cause an underhood fire when overloaded. |
| Maximum peak
| The highest voltage recorded over a specific time period |
| Maxwell's Law
| James Clerk Maxwell (1831 - 1879) did revolutionary work in electromagnetism and kinetic theror of gasses. Maxwell showed that a few relatively simple mathematical equations could express the behavior of electric amd magnetic fields and their interrelated nature. |
| MBT
| Maximum best torque |
| MC
| Mixture Control |
| MCCC
| Modulated converter clutch control |
| MCS
| Mixture control solenoid |
| MCU
| An acronym for microprocessor control unit. |
| MCV
| Mixture control valve |
| Md
| Mendelevium An element with the atomic number of 101 |
| MDPS
| Manifold differential pressure sensor |
| MEA
| An acronym for Mechanics' Education Association. |
| mean
| 1. A top performing driver. 2. A car tough to beat in a race. |
| mean effective pressure (MEP)
| The average pressure developed within an engine cylinder during a four-stroke cycle. |
| mean motor scooter
| A top-performing car in drag racing. |
| mean rating
| A more accurate rating than absolute rating or nominal rating. |
| measuring
| The act of determining the size, capacity, or quantity of an object. |
| meat
| The structural metal often found in an engine block. |
| meats
| 1. Big tires. 2. Drag racing slicks. |
| MECA
| An acronym for Manufacturers of Emission Controls Association |
| mechanic
| A worker who repairs machines |
| mechanic's wire
| Bendable steel wire used to attach or fasten parts or other objects together. |
| mechanical fade
| Brake fade due to heat expansion of a brake drum away from the shoes and linings. Mechanical fade does not occur with disc brakes. |
| MECS
| Mazda equipped control system or Mazda engine control system |
| mega
| The prefix representing the number 1,000,000 |
| Mega samples per second
| A sample rate unit equil to one million samples per second |
| megahertz
| (MHz) One million cycles per second. |
| Megnetic Reluctance
| The resistance of a magnetic path to the flow of magnetic flux lines through it |
| megohm
| (M0) A million Ohms. |
| MEM-CAL
| Memory Calibration Package |
| Membrane
| 1. The separating layer in a fuel cell that acts as an electrolyte, as well as a berrier film separating the gases in the anode and cathode compartments of the fuel cell. |
| Menu
| A list of choices for selecting a confifuration or feature |
| metal deactivator
| Gasoline additive used to neutralize the effect of copper compounds found in gasoline |
| metallic lining
| Break friction material made from powered metal that is formed into blocks by heat and pressure. |
| Meter Mode
| Setting an oscilloscope to display digits as with a multimeter |
| metering device
| A device for metering the proper amount of refrigerant into an evaporator. The two types for automotive air conditioning systems are thermostatic expansion valve (TXV) and orifice tube (OT) |
| metering valve
| A hydriodic control valve used primary with front disc breaks on RWD vehicles. The metering valve delays pressure application to the front brakes until the rear drum brakes have started to operate providing better control and stopping power. |
| methanol
| (methyl alcohol, wood alcohol) Typically manufactured from natural gas. In the 1980's methanol was used in combination with heavier co-solvents alcohols as an octane enhancer for addition to gasoline. Methanol is not typically blended into today's gasolines, however methanol is being considered as a "neat" (pure) fuel in specially designed vehicles. |
| mfd
| Micro-farad |
| MFI
| Mechanical fuel injection, or Multi-port fuel injection |
| Mg
| Magnesium An element with the atomic number of 12 |
| MHC
| Motor home chassis |
| mho
| The unit of conductance or admittance. The inverse of resistance |
| MHZ
| Mega-hertz |
| mica
| A mineral with excellent insulating and heat resistant qualities, hence it is used for dielectrics and insulators. |
| Michael Faraday
| Michael Faraday ( 1791 - 1867 ) an English Physicist The measurement of the capacity of a condenser of capacitor is masured in units called FARADS for Faraday |
| micro
| The prefix representing the number 0.000,001 |
| Microprocessor
| [1] A data processor with electronic integration capabilities. [2] A digital computer or processor built on a single integrated circuit chip [3] A microprocessor can perform functions of arithmetic logic and control logic itis the basic building block of a microcomputer system such as thoes used in automotive applications. |
| midget
| A small, oval-track racing car. |
| midnight auto parts
| Parts that were stolen. Also known as midnight auto supply. |
| midpositioned
| The position of a stem-type service valve where all fluid passages are interconnected. |
| midseated
| An incorrect term used for midpositioned. |
| MIG
| An acronym for metal inert gas. |
| MIG welding
| A term used for metal inert gas welding. |
| mil
| [1] an acronym for mili 1/1000 [2] an acronym for Milfunction Indicator Lamp an amber dash board worning light that may be labled "check engine" or "service engine soon" indicating that the ondboard diagnostic systim has determined that a problem exists.[3] A short term for an engine |
| mild steel
| A steel alloy with a low carbon content. |
| miles per gallon (mpg)
| The distance, in miles, a vehicle with travel per gallon of fuel. |
| miles per hour (mph)
| An indication of distance/time traveled. |
| military standard (MS)
| A system of grading the quality of fasteners and other items. |
| mill
| An engine. |
| milli
| The prefix representing the number 0.001 |
| milliampere (ma)
| A metric unit of electrical measure. |
| millimeter (mm)
| A metric unit of linear measure. |
| millivolt (mV)
| One thousandth of a volt |
| milliwatt (mW)
| One thousandth of a watt. |
| Min-Max
| A feature that increases its sampling rate to the maximum level and displays the maximum, minimum and adverage voltage levels recorded |
| mini stock
| A category for four-cylinder, sub-compact vehicles on an oval track. |
| minimum forward reduction
| Simple planetary-gear-set combination with the ring gear as input, the planetary carrier output, and the sun gear held. |
| Minimum idle air
| Air that passes the throttle plate to the throttle bore opening not subject to computer control |
| minimum peak
| The lowest voltage recorded over a specific time period |
| minimum thickness
| The lower limit if the thickness required after metal has been removed from an item such as a brake disc, to retain its integrity. |
| minispare tire
| A compact spare tire. |
| minor diameter
| 1. The smallest diameter of a cylinder. 2. The smallest diameter of a bold thread. |
| minor overhaul
| An engine-repair procedure that includes a valve job, replacing the piston rings, the rod bearings, and the gasket set. |
| minor tune-up
| An engine-maintenance procedure performed on distributor ignition vehicles that includes only the replacement of parts found to be defective. |
| MISAR
| Micro processed sensing automatic regulation |
| miscibility
| The property that allows one fluid to blend with other fluids. |
| misfire
| An intermittent or continuous failure to ignite the air/fuel mixture in one or more cylinders. |
| miss
| A brief engine hesitation such as a misfire. |
| missing teeth
| 1. A condition found in a synchronous belt drive that may be caused by under-tensioning, misalignment, or excessive shock loads. 2. Teeth broken off a gear. |
| Mitsubishi Jet Valve
| A tiny third valve that admits nothing by air to churn up the air/fuel charge and promote lean running and a complete burn. |
| Mityvac
| A hand held vacuum tool used to produce and measure a vacuum |
| mixing
| 1. To blend or combine. 2. To use parts, such as tires, of two or more sizes or types. |
| mixing chamber
| That part of an apparatus in which a fuel gas, and oxygen or air are mixed. |
| mixture adjustment
| To adjust the portions of a mixture, such as air and fuel. |
| Mixture Control Solenoid
| A device installed in a carburetor which regulates the air/fuel ratio |
| MK
| An acronym for master kit. |
| MKT
| An engine parts kit that contains all of the parts found in an MK plus the timing gears. |
| ML
| (Porsche) Air Mass |
| MLP
| Manual lever position |
| MLPS
| Manual lever position sensor |
| MLUS
| Modulated lock up solenoid |
| mm
| Millimeter |
| MMC
| An acronym for metal matrix composite. |
| MMT
| An acronym for Methylcyclopentadienyl Manganese Tricarbonyl A Metalic compound used in Canada as an Octane improver |
| Mn
| Manganese An element with the atomic number of 25 |
| Mo
| Molybdenum An element with the atomic number of 42 |
| Mobile Air Conditioning Society (MACS)
| A nonprofit organization founded in 1981 for the dissemination of distribution of comprehensive technical information, training, and communications to its members consisting of automotive air-conditioning shops, installers, distributors, supplies, and manufacturers in the United States and Canada. |
| Mobile5A
| A model for vehicle emissions |
| mode
| A term generally used to describe a particular set operating characteristics. |
| mode door
| A diverter door within the duct system for directing air through the heater and / or evaporator core. |
| model year
| The year of vehicle manufacture, as designated by the manufacturer; not consistent with the calendar year. |
| modem
| An acronym for modulator-demodulator; a modem is a device and/or program that enables a computer to transmit data over telephone lines. |
| modesty panel
| The panel below the bumpers that conceals the chassis components. Also known as modesty skirt. |
| modesty skirt
| Same as modesty panel. |
| modification
| To alter or change from the original. |
| modified
| A vehicle that has been reworked for high-performance operation. |
| modified MacPherson strut
| A type of MacPherson strut suspension that uses shock struts with coil springs mounted between the lower arms and spring pockets in the cross member, to absorb minor road vibrations by the chassis rather than fed back to the driver through the steering system. |
| modified strut
| A strut suspension where the coil spring is not part of the assembly and is independently located between the lower control arm and the frame. |
| modular wheel
| A wheel made of different sections that are bolted or riveted together. |
| modulated vacuum
| A vacuum signal regulated to a particular level. |
| modulator
| 1. A device that varies the frequency amplitude and phase of electromagnetic waves. 2. A device that regulates hydraulic line pressure in a transmission to meet varying load conditions. |
| module
| A semi-conductor control unit for an electronic-ignition fuel or any other system. |
| modulus of elasticity
| The point at which a material has been bent too far to snap back into shape. |
| moisture
| Humidity, dampness, wetness, or small droplets of water. |
| moisture ejector
| A valve mounted to the bottom or side of the supply and service reservoirs that collects water and expels it every time the air pressure fluctuates. |
| mold
| 1. A hollow form into which molten metal is poured to form a part. 2. A fungus. 3. To form or shape an object. |
| mold-bonded linings
| A pad assembly made by applying adhesive to the pad and then pouring the uncured lining material onto the pad in the mold. The assembly is cured at high temperatures to fuse the lining and adhesive to the pad. |
| molded
| To rejoin body panels using a filler material to conceal the seam. |
| molded connector
| A male or female electrical connector usually having one to four wires that are molded into a one-piece component. |
| molded curved-radiator hose
| A term used for preformed radiator hose. |
| molded hose
| A section f hose permanently formed to fit a particular application. |
| Mole Wrench
| English term for Vise Grips |
| molecular sieve
| A drying agent. |
| molecule
| Two or more atoms chemically bound togather. |
| Molten Carbonate
| 1. A type of fuel cell electrolyte that contains carbon, Oxygen and another element. Solid at room temp., it must be melted in order to function. |
| moly
| Short for molybdenum. |
| moly lube
| A lubricant popular for coating engine parts during rebuilding to avoid an initial dry start up. |
| moly ring
| A piston ring with a molybdenum coating. |
| molybdenum
| An element (Mo) used in some steel alloys to add hardness and strength. |
| molybdenum disulfate
| A combination of molybdenum (Mo) and sulfur (S) sometimes added to oil and grease to improve their lubricating qualities. |
| moment of inertia
| The tendency of a body to resist angular or rotational acceleration, such as a vehicle resisting a cornering effort. |
| momentum
| The force of continuing motion. The momentum of a moving object equals its mass times its speed. |
| MON
| An acronym for motor octane number. |
| monel
| An alloy of nickel (Ni) and copper (Cu). |
| money grabber
| A driver who enters and starts a stock car race but leaves after a minimum number of laps, collecting appearance money but not racing seriously. |
| money pit
| A vehicle that is expensive to restore and/or maintain. |
| monitor
| 1. An electronic sensor, such as the lambda sensor. 2. In computer terms a monitor is a display screen. |
| monkey motion
| The excessive movement of a mechanical device, such as an improperly adjusted carburetor linkage. |
| monochlorodifluoromethane
| The chemical term for refrigerant-22 (HCFC-12) |
| monocoque
| A unitized autobody-frame structure with stresses-sheet-metal body panels. |
| monogoggle
| Eye protection that may be worn over glasses. |
| monoleaf spring
| A spring that is made up of a single steel leaf. |
| monolithic
| A device or structure made as a single unit. |
| monolithic catalytic converter
| A catalytic converter which has its catalytic materials coating a ceramic honeycomb, as distinguished from the pellet-bed converter. |
| Monolithic Substrate
| The ceramic honeycomb structure used as a base to be coated with a metillic catalyst material for use in the converter |
| monolithic timing
| The use of an electronic timing device to make precise adjustments in engine timing when the engine is running. |
| monster truck
| A truck, usually a pick-up, having huge, oversized wheels and tires with a heavy duty power train to drive them. |
| Montreal protocol
| An agreement signed by representatives of the participating countries to reduce CFC and HCFC emissions into the atmosphere by restricting and regulating the manufacture and sale of such products. |
| moon disc
| A smooth hub cab that completely covers the wheel. |
| MOS
| Metal Oxide Semiconductor |
| MOS transistor
| A Metal Oxide Semiconductor used as a field-effect transistor made from a sandwich of metal for a gate, on tor of oxide, on to of the semiconductor substrate which contains the source and drain. |
| MOSFET
| Metal Oxide Semiconductor Field-effect transistor |
| motor
| A device that converts electrical energy into mechanical energy, such as a fan motor. |
| Motor and Equipment Manufacturers Association (MEMA)
| An association of manufacturers of automotive aftermarket parts, original equipment parts, tools, chemicals, and other products. |
| motor home
| A self-contained vehicle built on a bus or truck chassis containing a driver's compartment and complete living facilities. |
| motor mounts
| Supports made of hard rubber for the engine and transmission to be secured to the vehicles frame. |
| motor mouth
| An overly talkative person. |
| motor octane number (MON)
| A term used for octane number. |
| motor oil
| A lubricant expressly formulated for use in an engine. |
| motor town
| Detroit, Michigan. |
| motor vehicle
| A machine, usually on rubber tires, that is propelled by means other than muscle power, and which does not operate on rails. |
| Motor Vehicle Manufactures Association (MVMA)
| A trade association of the major automobile and truck manufactures in the United States. |
| MoTown
| 1. The name of a Detroit-based record company. 2. Short for motor town or Detroit. |
| Motronic
| A Bosch electronic fuel-injection and ignition-management system. |
| mount and drive
| Pulleys, mounting plates, belts, and fittings necessary to mount a compressor and clutch or any other engine driven assembly on an engine. |
| mountain motor
| A big block V-8, usually Chevrolet or Ford, enlarged to 500 cid or more; often to as much as 600 to 800 cid. |
| mounting grommet
| 1. The replaceable rubber bushings used at both ends of the shocks for mounting to reduce the transfer of sounds and jarring motions between the shocks and their mounting points on the vehicle. 2. A reinforced eyelet through which a fastener is attached. |
| mounting position
| The position at which a device is mounted, such as horizontal or vertical. |
| mouse
| A computer input device for moving a cursor or data around on the display screen. A way to point and click |
| mouse milk
| An additive for oil or fuel. |
| mouse motor
| A Chevrolet small-block V-8. |
| moving vehicle resistance
| A measure of the air resistance of an auto body design. |
| MPA
| Managed pulse air |
| MPC
| Manifold Pressure Controlled fuel injection system. A fuel injection system which determines engine load based upon intake manifold pressure |
| MPFI
| Multi-port fuel injection |
| mpg
| An acronym for miles per gallon. |
| mph
| An acronym for miles per hour. |
| MPI
| Multi-point injection |
| MPSI
| An acronym for Micro Processor System Integrations Company. A manufacturer of automotive scantools and other electronic equipment. |
| MPU
| Micro processor unit |
| MS
| An acronym for military standard. |
| MSDS
| An acronym for Material Safety Data Sheet. Information sheets issued by the manufacturer of hazardous materials. An MSDS provides detailed information concerning any dangerous ingredients, corrosiveness, reactivity, toxicity, fire, or explosion danger data. |
| MTA
| Managed thermactor air |
| MTBE
| An acronym for methyl tertiary butyl ether. An ether manufactured by reacting methanol and isobutylene. The resulting ether is higher in octane and lower in volatility. MTBE is a fuel oxygenate and is permitted in unleaded gasoline up to a level of 15% |
| MTEG
| An acronym for Mickey Thompson Entertainment Group. |
| mud and snow tire
| 1. An all-season tire. 2. A term used for snow-and-mud tire. |
| mud flap
| A flap hanging down behind a tire to prevent the tire from throwing debris against the lower panel of the vehicle or into the path of a following vehicle. |
| mud plug
| A cap installed in the center of a wheel to keep out mud and other debris. |
| mud-bogging
| Racing an off-road vehicle through a 100-200 foot (30-61 meter) mud hole. |
| muffler
| 1. A hollow, tubular device used in the lines of some air conditioners to minimize the compressor noise or surges transmitted to the inside of the car. 2. A device in the exhaust system used to reduce noise. |
| muffler bearing
| A non-existing part. |
| muffler clamp
| A clamp that secures the muffler, or pipe, to the bracket or hanger. |
| muffler hanger
| A hanger that is used to secure the muffler. |
| mule
| 1. A yard tractor not suitable for over-the-road service. 2. A road race car used for practice or testing. |
| Multec Injector
| An injector that is designed with a high degree of anti-clogging qualities. |
| Multi port Fuel injection
| Individual injectors for each cylinder are mounted in the intake manifold |
| multi-fuel vehicle
| A vehicle having a modified engine that runs on more than one fuel, such as LPG and gasoline. |
| multi-leaved spring
| A flat suspension spring having more than one leaf. |
| multimedia
| The use of computers to present text, graphics, video, activation, and sound in an integrated way. |
| multimeter
| A multi-range meter used to measure voltage, current, and resistance |
| multiple disc
| A clutch with several driving and driven discs. |
| multiple pass
| A term that applies to a recovery/recycle unit that removes refrigerant from an air-conditioning system and circulates it through the recovery/recycle unit to remove |
| multiple-disc clutch
| 1. A clutch that consists of alternating friction and steel discs that are forced together hydraulically to lock one transmission part to another. 2.A clutch having a large drum-shaped housing that can be a separate casting or a part of the transmission housing. |
| multiple-leaf spring
| Leaf springs having a series of flat, steel leaves of varying lengths clamped together with a center bolt extending through them to maintain their position. |
| multiplex
| 1. The ability to transmit two or more signals over a single channel simultaneously. 2. The ability to select one of a multiple of input signals to appear at an output during a particular time period. |
| Multiplexing
| A means of transmitting information between computers. |
| mutual induction
| The generation of an electric current due to a changing magnetic field of an adjacent coil. |
| mV
| Milli-volts |
| MVS
| Metering valve system |
Auto & Car Glossary
