Dodge ram truck 3500 1996 Service Manual page 1277

BR FUEL SYSTEM 14 - 43
DESCRIPTION AND OPERATION (Continued)
ator pedal cable, speed control cable and transmis­
sion control cable (when equipped) are connected to
the throttle arm.
A (factory adjusted) set screw Is used to mechani­
cally limit the position of the throttle body throttle
plate. Never attempt to adjust the engine idle
speed using this screw. All Idle speed functions are
controlled by the PCM.
THROTTLE BODY—8.0L ENGINE
Filtered air from the air cleaner enters the intake
manifold through the side mounted throttle body
(Fig. 82). Fuel does not enter the intake manifold
through the throttle body. Fuel Is sprayed into the
manifold by the fuel injectors. The throttle body Is
mounted on the Intake manifold, i t contains an air
control passage (Fig. 33) controlled by an idle air con­
trol (IAC) motor. The air control passage is used to
supply air for Idle conditions. A throttle valve (plate)
is used to supply air for above idle conditions.
INTAKE MANIFOLD
UPPER
HALF
NUTS (4) J9414-57
Fig. 82 Throttie Body—8.0L Engine
The throttle position sensor (TPS) and idle air con­
trol (IAC) motor are attached to the throttle body.
The accelerator pedal cable, speed control cable and
transmission control cable (when equipped) are con­
nected to the throttle arm.
A (factory adjusted) set screw is used to mechani­
cally limit the position of the throttle body throttle
plate. Never attempt to adjust the engine idle
speed using this screw. All idle speed functions are
controlled by the PCM.
VACUUM
FITTING
PASSAGE CONTROL (IAC)
MOTOR
VIEW FROM BOTTOM J9414.48
Fig. 33 Air Controi Passage—8.0L Engine
D I A G N O S I S A N D T E S T I N G
VISUAL INSPECTION—3.9L/5.2L/5.9L ENGINES
A visual inspection for loose, disconnected or incor­
rectly routed wires and hoses should be made. This
should be done before attempting to diagnose or ser­
vice the fuel injection system. A visual check will
help spot these faults and save unnecessary test and
diagnostic time. A thorough visual inspection will
include the following checks:
(1) Verify that the three 32-way electrical connec­
tors are fully inserted into the connector of the pow­
ertrain control module (PCM) (Fig. 34).
Fig. 34 Powertrain Controi Module (PCM)