For coil pack applications not using engine analyzer:
GO to JB20
.
For coil on plug applications:
GO to JB15
.
JB2 CONNECT ENGINE ANALYZER
Obtain an Engine Analyzer to diagnose concerns in the secondary side of the ignition system. Note: In order for the diagnostic procedures to provide accurate results, it is essential that the calibration of the engine analyzer be maintained. Refer to the equipment manual for the procedure to calibrate the engine analyzer. If the equipment manual is not available, an estimate of the calibration can be made by connecting the Spark Tester D81P-6666-A or equivalent to a properly operating ignition system and measuring the firing voltage of the spark tester only. The spark tester firing voltage should be approximately 12KV. Is the engine analyzer connected? Yes
GO to JB3
.
No
GO to JB2
.
JB3 CHECK FOR IGNITION PATTERN
Observe pattern on scope while cranking engine.
Is the pattern flat which indicates no spark on all cylinders? Yes
: IGN START/RUN circuit concern. CHECK condition
of related fuses/fuse links. If OK, REPAIR open circuit. If fuse/fuse link
is damaged, CHECK IGN START/RUN circuit for short to ground. REPAIR as necessary.
COMPLETE Misfire Monitor Repair Verification Drive Cycle (REFER to Section
2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles).
No
GO to JB4
.
JB4 CHECK FOR NORMAL IGNITION PATTERN
Note:Spark plugs are fired up to four strikes per firing. Multi-strike operating mode is dependent on the PCM calibration and is limited to less than 2000 rpm. Above 2000 rpm, spark plugs are fired once per firing.
INSPECT spark plug wire and spark plug for missing cylinder.
MEASURE resistance of spark plug wire. REPLACE if greater than 7,000 ohms
per 30.5 cm (1 foot). MEASURE resistance of spark plug. REPLACE if lower than
2000 or higher than 20000 ohms. COMPLETE Misfire Monitor Repair Verification
Drive Cycle (REFER to Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles).
Check the spark plug firing voltage average pattern.
Is there consistently low spark plug firing voltage or sloping spark line on one or more cylinders? Yes
INSPECT spark plug wire and spark plugs. MEASURE resistance
of spark plug wires. REPLACE if greater than 7,000 ohms per 30.5 cm (1 foot).
MEASURE resistance of spark plugs. REPLACE if lower than 2000 or higher than
20000 ohms. COMPLETE Misfire Monitor Repair Verification Drive Cycle (REFER
to Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles).
No
GO to JB9
.
JB9 CHECK FOR EVENESS BETWEEN CYLINDERS
Check the spark plug firing voltage average pattern.
Is the evenness of spark plug firing voltage greater than 6KV? Yes
Inspect spark plug wires and spark plugs. MEASURE resistance
of spark plug wires. REPLACE if greater than 7,000 ohms per 30.5 cm (1 foot).
CHECK for damaged spark plugs or narrow spark plug gaps. MEASURE resistance
of spark plugs. REPLACE if lower than 2000 or higher than 20000 ohms. COMPLETE
Misfire Monitor Repair Verification Drive Cycle (REFER to Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles).