Chrysler RAM TRUCK 2500 1994 Service Manual page 375

8D - 18 IGNITION SYSTEMS
•
• I f voltage remains at near battery voltage during
the entire 5 seconds, turn the key off. Remove the 60-
way connector (Fig. 24) from the powertrain control
module (PCM). Check 60-way connector 'for any
spread terminals.
o o o o o o o o o o
^ o o o o o o o
^oooooooooo
S o o o o o o o o o o
11 20
^ Q P O O O O O O O
i
|
5 i ? i
o o o o o o o o o ;
O O O O O O O O O O '
C O N N E C T O R
TERMINAL SIDE
S H O W N
J908D-42
Fig. 24 PCM 60-Way Connector
(5) Remove test lead from the coil positive termi­
nal. Connect an 18 gauge jumper wire between the
battery positive terminal and the coil positive termi­
nal.
(6) Make the special jumper shown i n Figure 25.
Using the jumper, momentarily ground terminal-19
of the 60-way connector. A spark should be generated
at the coil cable when the ground is removed.
CAPACITOR >
GROUND
THIS
CLIP
CONNECT THIS-
CLIP TO COIL
N E G A T I V E
ALLIGATOR CLIP
/
ALLIGATOR
r r ^ * * ^ ^ CLIP
: ^ 3 . M F ' . (MOMENTARILY
— — " : : ' 1 G R O U N D THIS
CLIP T O COIL 1
NEGATIVE
RBI003
Fig. 25 Special Jumper Ground-to-Coil Negative
Terminal
(7) I f spark is generated, replace the powertrain
control module (PCM).
(8) I f spark is not seen, use the special jumper to
ground the coil negative terminal directly.
(9) I f spark is produced, repair wiring harness for
an open condition.
• (10) I f spark is not produced, replace the ignition
coil.
IGNITION TIMING
Base (initial) ignition timing is NOT adjust­
able on any engine. On a 3.9L V-6 or a 5.2/5.9L
V-8 engine, do not attempt to adjust ignition
timing by rotating the distributor.
All ignition timing functions are controlled by the
powertrain control module (PCM). Refer to On-Board
Diagnostics i n the Multi-Port Fuel
Injection—General Diagnosis section of Group 14,
Fuel Systems for more information. Also refer to the
appropriate Powertrain Diagnostics Procedures ser­
vice manual for operation of the DRB Scan Tool.
INTAKE MANIFOLD AIR TEMPERATURE SENSOR
TEST
On 3.9L V-6 or 5.2/5.9L V-8 engines, the sensor is
threaded into the right-front side of the intake man­
ifold (Figs. 26 or 27).
On 8.0L V-10 engines, the sensor is threaded into
the left side of the intake manifold near the front of
the throttle body (Fig. 28).
SUPPORT BRACKET
INTAKE
MANIFOLD
AIR
TEMPERATURE
S E N S O R
J9414-12
Fig. 26 Sensor Location—3.9L V-6 Engine—Typical
INTAKE MANIFOLD
AIR TEMPERATURE
SENSOR
J9314-162
Fig. 27 Sensor Location—5.2L/5.9L V-8 Engines-
Typical
To perform a complete test of the intake manifold
air temperature sensor and its circuitry, refer to the
DRB scan tool. Also refer to the appropriate Power-
train Diagnostics Procedures manual. To test the sen­
sor only, refer to the following:
(1) Disconnect the wire harness connector from the
sensor.
(2) Test the resistance of the sensor with a input
impedance (digital) volt-ohmmeter. Do not remove
the sensor from the engine for testing. For resistance