PCV SYSTEM
Breather- The breather system seals crankcase blow-by gases and routes them to the intake for combustion. Most cars use a vacuum operated PCV system to accomplish this.

PETCOCK
The fuel valve, usually found on the side of the gas tank.

PINGING
Metallic noise produced by a faulty combustion cycle inside the cylinder also known as Knocking.

PISTON
A partly hollow, cylindrical metal engine part that is closed at one end and fits into the engine cylinder. Connected to the crankshaft via the connecting rod and usually fitted with rings to seal it in the cylinder.

PLANAR LAMBDA OXYGEN SENSOR
In its basic operating concept the planar sensor corresponds to the heated finger-type element sensor by generating a response curve with a characteristic jump at lambda=1. At the design level the planar sensor is distingguished from the finger-type unit.

PLUGS
One example of the available connection techniques is the plug connection at the high-voltage terminial towers of the ignition distributor. Socket version A has only a relatively low high-voltage strength and is thus encountered only in isolated cases in orignial equipment applications.

POLLUTANT EMISSION
The ignition angle Az or the ignition point has an important influence on the exhaust-gas values, the torque the fuel consumption and the driveability of the spark-igniton engine. The most important pollutants in the exhaust gas are the unburned hydrocarbons (HC), oxides of nitrogen (NOx) and carbon monoxide (CO).

POLARIS
A brand of motorcycle, atv and snowmobile produced in the United States.

POST-START ENRICHMENT
Enrichment with additional fuel improves the post-start performance at low temperatures. This function is calibrated to give satisfactory throttle response at all temperatures together with minimum fuel consumption.

POST-START PHASE
Following low-temperature starts, supplementary fuel is required for a brief period, until the combustion chamber heats up and improves the internal mixture formation. This richer mixture also increase torque to furnish a smoother transition to the desired idle speed.

POWER COMMANDER
Fuel injection product from Dynojet.

PRESSURE CHARGING
Because maximum possible torque is proportional to fresh-air charge density, it is possible to rsie power output by compressing the air before it enters the cylinder.

PSI
Pounds per square inch, the common unit of measurement for pressure. Normal atmospheric pressure at sea level is 14.7 psi.