6E±580
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Throttle Body Unit
The throttle body has a throttle plate to control the amount
of air delivered to the engine. The TP sensor are also
mounted on the throttle body. Vacuum ports located
behind the throttle plate provide the vacuum signals
needed by various components.
Engine coolant is directed through a coolant cavity in the
throttle body to warm the throttle valve and to prevent
icing.
025RY00005
General Description (Electronic
Ignition System)
Crankshaft Position (CKP) Sensor
The crankshaft position (CKP) sensor provides a signal
used by the powertrain control module (PCM) to calculate
the ignition sequence. The sensor initiates the 58X
reference pulses which the PCM uses to calculate RPM
and crankshaft position. Refer to
Electronic Ignition
System
section for additional information.
Electronic Ignition
The electronic ignition system controls fuel combustion
by providing a spark to ignite the compressed air/fuel
mixture at the correct time. To provide optimum engine
performance, fuel economy, and control of exhaust
emissions, the PCM controls the spark advance of the
ignition system. Electronic ignition has the following
advantages over a mechanical distributor system:
No moving parts.
Less maintenance.
Remote mounting capability.
No mechanical load on the engine.
More coil cooldown time between firing events.
Elimination of mechanical timing adjustments.
Increased available ignition coil saturation time.
0013
Ignition Coils
A separate coil-at-plug module is located at each spark
plug. The coil-at-plug module is attached to the engine
with two screws. It is installed directly to the spark plug by
an electrical contact inside a rubber boot. A three-way
connector provides 12-volt primary supply from the
15-amp ignition fuse, a ground-switching trigger line from
the PCM, and a ground.
060RY00022
Ignition Control
The ignition control (IC) spark timing is the PCM's method
of controlling the spark advance and the ignition dwell.
The IC spark advance and the ignition dwell are
calculated by the PCM using the following inputs:
Engine speed.
Crankshaft position (58X reference).
Engine coolant temperature (ECT) sensor.
Throttle position (TP) sensor.
ION sensing module.
Park/Neutral position (PRNDL input).
