Engines - Chrysler RAM TRUCK 2500 1994 Service Manual

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Fig. 9 Crankshaft Position Sensor—8.0L V-10
Engine—Typical
Fig. 10 Sensor Operation—8.0L V-10 Engine
needed. I t may take the module up to one complete
engine revolution to determine crankshaft position
during engine cranking.
The PCM uses the signal from the camshaft posi­
tion sensor to determine fuel injector sequence. Once
crankshaft position has been determined, the PCM
begins energizing a ground circuit to each fuel injec­
tor to provide injector operation.
DISTRIBUTORS—3.9L V-6 OR 5.2/5.9L V-8
ENGINES
For component testing, refer to the Diagnostics/Ser­
vice Procedures section of this group.
All 3.9L V-6 and 5.2L/5.9L V-8 engines are
equipped with a camshaft driven mechanical distrib­
utor, containing a shaft driven distributor rotor. They
are equipped with an internal camshaft position (fuel
sync) sensor. This sensor provides fuel injection syn­
chronization and cylinder identification.
Distributors do not have built in centrifugal or vac­
uum assisted advance. Base ignition timing and all
IGNITION SYSTEMS 8D - 5
timing advance is controlled by the powertrain con­
trol module (PCM). Because ignition timing is con­
trolled by the PCM, base ignition timing is not
adjustable on any of these engines*
The distributor is held to the engine i n the conven­
tional method using a holddown clamp and bolt. Al­
though the distributor can be rotated, it will
have no effect on ignition timing.
All distributors contain an internal oil seal that
prevents oil from entering the distributor housing.
The seal is not serviceable.
For removal and installation of this component, re­
fer to the Component Removal/Installation section of
this group.
IGNITION COIL—3.9L V-6 OR 5.2/5 J L V-8
ENGINES
3.9L V-6 o r 5.2/5.0L V-8 LDC-Gas Engines; The
coil is mounted to a bracket that is bolted to the
front of the right engine cylinder head (Fig. 11). This
bracket is mounted on top of the automatic belt ten­
sioner bracket using common bolts.
5.9L V-8 HDC-Gas Engine: The coil is mounted to
a bracket that is bolted to the air injection pump
(AIR pump) mounting bracket (Fig. 12).
Fig. 11 Ignition Coil—3.91 V-6 or 5.2/5.9L ¥-8
LDC-Gas Engines
The ignition coil is not oil filled. The windings are
embedded i n an epoxy compound. This provides heat
and vibration resistance that allows the ignition coil
to be mounted on the engine.
The automatic shutdown (ASD) relay, after receiv­
ing signals from the crankshaft and camshaft posi­
tion sensors, will supply battery voltage to the
ignition coil positive terminal. I f these signals are not
received by the PCM after approximately one second
of engine cranking (start-up), the ASD relay will shut
off positive voltage to the coil. Coil operation (firing)
is then controlled by switching ground circuits (off-
and-on) through the PCM. The PCM will determine