P

PART THROTTLE MODE - Same as "closed throttle mode".

PARTICULATE - A tiny bit of solid matter found in exhaust gases.
PARTS PER MILLION - A measure used in emission analyses. Abbreviation is PPM or ppm.


PCV - Abbreviation for Positive Crankcase Ventilation.


PERCOLATION - Undesirable condition during hot soak in which heat causes the air or fuel in the float bowl to expand so that fuel is forced into the intake manifold. A properly working float bowl vent should prevent percolation.


PHOTOCHEMICAL - Term describing the action of light (photo) on air pollutants (chemicals), which creates smog.


PORTED PRESSURE SWITCH - PPS


PORTED VACUUM - Vacuum tapped from a passage just above the throttle plate in a carburetor.

Ported Vacuum Switch:

PORTED VACUUM SWITCH (PVS) - A temperature actuated switch that changes vacuum connections when the coolant temperature changes.

2.3L Positive Crankcase Ventilation System:

POSITIVE CRANKCASE VENTILATION SYSTEM (PCV) - An emission-control system that routes engine crankcase fumes into the intake manifold or air cleaner, where they are drawn into the cylinders and burned along with the air/fuel mixture. Abbreviation is PCV.
POSITIVE CRANKCASE VENTILATION VALVE (PCV) - A valve which controls the flow of vapors from the crankcase into the engine.


PPM or ppm - Abbreviation for parts per million.


PRESSURE FEEDBACK EGR (PFE) SENSOR - Ceramic capacitance pressure sensor that signals EGR flow. If measures pressure in the chamber below the EGR valve.


PROCESSOR - The "on-board" computer that receives data from a number of sensors and other electronic components. Based on input data information programmed into the processor's memory, the processor generates output signals to control various engine functions.

Profile Ignition Pickup:

PROFILE IGNITION PICKUP (PIP) - A "Hall Effect" Vane Switch sensor furnishes crankshaft position information to the processor. Replaces the crankshaft position sensor in EEC-IV applications.
PSOV - See "Canister Purge Shut Off Valve."


PULSE AIR SYSTEM - A type of exhaust emission control system which uses the natural exhaust pulses in a turned pipe. A reed-type check valve responds to the negative pressure pulses and permits air to be drawn into the exhaust system.

Purge Control Valve:

PURGE CONTROL VALVE (Purge CV) - Valve used to control the release of fuel vapors from the charcoal cannister into the engine.
PURGE SOLENOID - Device used to control the operation of the purge valve in evaporative control emission systems.