Subsection 03 (IGNITION SYSTEM)
IGNITION SYSTEM
SERVICE TOOLS
Description
Part Number
Page
ECM ADAPTER TOOL...................................................................
529 036 166 ......................................... 2, 4
FLUKE 115 MULTIMETER ............................................................
529 035 868 ......................................... 3–4
GENERAL
SYSTEM DESCRIPTION
The battery supplies the primary side of ignition
coils through the main relay (R2) while the ECM
completes the circuit for each cylinder by switch-
ing it to ground at the right moment. The ECM
can detect an open and short circuit in the primary
winding but it does not check the secondary wind-
ing.
The Engine Management System (EMS) controls
the ignition system. For more information, refer
to
ENGINE MANAGEMENT
subsection.
Ignition Timing
Ignition timing is not adjustable.
TROUBLESHOOTING
It is good practice to check for fault codes using
the B.U.D.S. software as a first troubleshooting
step. Refer to
DIAGNOSTIC AND FAULT CODES
subsection.
Always refer to the
WIRING DIAGRAM
when
troubleshooting an electrical circuit.
Refer to
POWER DISTRIBUTION AND GROUNDS
for fuse and relay information.
Refer to
WIRING HARNESS AND CONNECTORS
for vehicle wiring harness layout and component
locations.
Refer to
ENGINE MANAGEMENT SYSTEM (EMS)
for powertrain wiring harness layout and compo-
nent locations.
DIAGNOSTIC GUIDELINES
The following is provided to help in diagnosing the
probable cause of a problem. It is a guideline and
should not be assumed to list all possible causes.
ENGINE WILL NOT START (ENGINE
TURNS OVER)
1.
Fouled or defective spark plug
- Replace.
2.
Defective CPS
- Check operation of CPS and replace if necessary.
Refer to ELECTRONIC FUEL INJECTION (EFI)
subsection.
3.
Defective trigger wheel
- Inspect trigger wheel. Refer to MAGNETO AND
STARTER subsection.
4.
Defective ignition circuit
- Check fuse 5 of fuse box 1, ignition coil and wiring
condition.
5.
Defective fuel pump
- Check fuel pump, refer to FUEL TANK AND FUEL
PUMP subsection.
6.
Defective fuel injectors or circuit
- Check fuel injectors, refer to ENGINE MANAGE-
MENT SYSTEM subsection.
ENGINE HARD TO START
1.
Spark plug faulty, fouled or worn out
- Check spark plug condition. Replace if necessary.
2.
Low fuel pressure
- Test fuel pressure, refer to FUEL TANK AND
FUEL PUMP subsection.
ENGINE MISFIRES, RUNS IRREGULARLY
1.
Fouled, defective, worn spark plugs
- Check/verify heat range/gap/replace.
2.
Damaged trigger wheel/loose CPS
- Inspect trigger wheel. Refer to MAGNETO AND
STARTER subsection.
3.
Defective ignition circuit
- Check ignition coil, fuse 5, and wiring condition.
4.
Poor engine grounds
- Check/clean/repair.
ENGINE CONTINUALLY BACKFIRES
1.
Fouled, defective spark plugs
- Clean/replace spark plugs.
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