Jeep Engines - Oljeep

364 MOPAR PERFORMANCE PARTS0Intake manifold air temperature sensorManifold absolute pressure (MAP) sensorThrottle position sensor (TPS)Camshaft position sensor signalDuring wide open throttle conditions, the following occurs:Voltage is applied to the fuel injectors with the ASDrelay via the PCM. The PCM will then control theinjection sequence and injector pulse width by turningthe ground circuit to each individual injector on andoff. The PCM ignores the oxygen sensor input signaland provides a predetermined amount of additionalfuel. This is done by adjusting injector pulse width.The PCM adjusts ignition timing by turning the groundpath to the coil on and off.During periods of high manifold vacuum, such as idle orcruising speeds, vacuum is sufficient to completelycompress the spring. It will then pull the plunger to the topof the valve. In this position there is minimal vapor flowthrough the valve.During periods of moderate manifold vacuum, the plungeris only pulled part way back from inlet. This results inmaximum vapor flow through the valve.O-RING\LOCATINGTABSIgnition Switch Off ModeWhen the ignition switch is turned to the OFF position, thePCM stops operating the injectors, ignition coil, ASD relayand fuel pump relay.POSITIVE CRANKCASE VENTILATION (PCV)SYSTEMThe 4.7L V-8 engine is equipped with a closed crankcaseventilation system and a Positive Crankcase Ventilation(PCV) valve.This system consists ofa PCV valve mounted to the oil filler housing (Figure6-20). The PCV valve is sealed to the oil filler housingwith an O-ring.0 the air cleaner housing.0 two interconnected breathers threaded into the rear ofeach cylinder head (Figure 6-21).0 tubes and hose to connect the system components.The PCV system operates by engine intake manifoldvacuum. Filtered air is routed into the crankcase through theair cleaner hose and crankcase breathers. The metered air,along with crankcase vapors, are drawn through the PCVvalve and into a passage in the intake manifold. The PCVsystem manages crankcase pressure and meters blow-bygases to the intake system, reducing engine sludge formation.The PCV valve contains a spring loaded plunger. Thisplunger meters the amount of crankcase vapors routed intothe combustion chamber based on intake manifold vacuum.When the engine is not operating, or during an engine popback,the spring forces the plunger back against the seat.This will prevent vapors from flowing through the valve.RUBBERHOSEFigure 6 - 20FRESH AIRFITTING1Figure 6 - 2 1LOCK-CRAN~KCASEBREATHERS (2)T '17