Chrysler RAM TRUCK 2500 1994 Service Manual page 374

IGNITION SYSTEMS 80 - 17
WARNING: B E V E R Y C A R E F U L WHEN T H E ENGINE
IS CRANKING. DO NOT PUT Y O U R HANDS NEAR
THE P U L L E Y S , BELTS OR T H E FAN. DO NOT W E A R
L O O S E FITTING CLOTHING.
(2) Rotate (crank) the engine with the starter mo­
tor and observe the cable terminal for a steady arc. If
steady arcing does not occur, inspect the secondary
coil cable. Refer to Spark Plug Cables in this group.
Also inspect the distributor cap and rotor for cracks
or burn marks. Repair as necessary. If steady arcing
occurs, connect ignition coil cable to the distributor
cap.
(3) Remove a cable from one spark plug.
(4) Using insulated pliers and taking care to pre­
vent damage to the cable, boot and terminal, hold the
cable terminal approximately 12 mm (1/2 in.) from
the engine cylinder head or block. Do this while ro­
tating the engine with the starter motor. Observe the
spark plug cable terminal for an arc. If steady arcing
occurs, it can be expected that the ignition secondary
system is operating correctly. If steady arcing occurs
at the spark plug cables, but the engine will not
start, connect the DRB scan tool. Refer to the Power-
train Diagnostic Procedures service manual.
FAILURE TO START TEST—EXCEPT 8 . 0 L V-10
ENGINE
To prevent unnecessary diagnostic time and wrong
test results, the previous Checking For Spark test
should be performed prior to this test.
WARNING: S E T PARKING B R A K E OR B L O C K T H E
DRIVE W H E E L S B E F O R E P R O C E E D I N G WITH THIS
TEST.
(1) Unplug the ignition coil harness connector at
the coil (Figs. 21 or 22).
Fig. 21 Coil Harness Connector—3.9L V-6 or
5.2/5.9L LDC-Gas Engines
Fig. 22 Coil Harness Connector—5.9L V-8 HDC-Gas
Engine
(2) Connect a set of small jumper wires (18 gauge
or smaller) between the ignition coil and the discon­
nected coil electrical connector (Fig. 23).
JUMPER
Fig. 23 Coil Terminals—3.9L V-6 or 5.2/5.9L V-8
Engines—Typical
(3) Determine that sufficient battery voltage (12.4
volts) is present for the starting and ignition sys­
tems.
(4) Connect the positive lead of the voltmeter to
the ignition coil (Fig. 23). Connect the negative lead
of the voltmeter to a good ground on the engine
block. Crank the engine for 5 seconds while monitor­
ing the voltage at the coil positive terminal (Fig. 23):
• If the voltage remains near zero during the entire
period of cranking, refer to On-Board Diagnostics in
Group 14, Fuel Systems. Check the powertrain con­
trol module and auto shut down relay.
• If voltage is at near battery voltage and drops to
zero after 1-2 seconds of cranking, check the power-
train control module circuit. Refer to On-Board Diag­
nostics in Group 14, Fuel Systems.