Pontiac Fiero 1988 Service Manual page 556

DRIVEABILITY AND EMISSIONS- FUEL INJECTION (TBI) 6E2-C4-9
©
©
©
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© IF ENGINE MISFIRES AT IDLE ONLY, SEE PAGE 1.
® IGNITION OFF.
• DISCONNECT ONE SPARK PLUG LEAD AT A TIME AND,
INSTALL SPARK TESTER (ST-125) J-26792 OR EQUIVALENT.
• OBSERVE SPARK TESTER WITH ENGINE IDLING. REPEAT
THIS TEST FOR ALL PLUG LEADS. SEE C A U T I O N *
• SPARK SHOULD JUMP TESTER GAP ON ALL LEADS WITH
ENGINE IDLING. DID IT?
NO
X
• IGNITION OFF, GROUND THE OPPOSITE PLUG
LEAD OF THE AFFECTED COIL AT SPARK PLUG.
© SPARK SHOULD JUMP TESTER GAP WHILE
CRANKING ENGINE. DOES IT?
NO
HE
• CHECK THE RESISTANCE OF EACH PLUG WIRE OF THE COIL
WHICH DID NOT FIRE THE SPARK TESTER.
• WIRE RESISTANCE SHOULD BE LESS THAN 30,000 OHMS EACH
AND WIRES SHOULD NOT BE GROUNDED. ARE WIRES OK?
YES
H
• REMOVE COIL RETAINING NUTS AND REMOVE COILS.
• COILS SHOULD BE FREE OF CARBON TRACKING. ARE T H E Y ?
YES
ZZ
• SWITCH A NORMALLY OPERATING COIL
WITH THE COIL FROM PROBLEM CYLINDER.
• SPARK SHOULD JUMP TESTER GAP WITH
ENGINE IDLING. DID IT?
YES
XI
ORIGINAL IGNITION
COIL IS FAULTY
CHART C-4D-2
'DIS" MISFIRE UNDER LOAD
2.5L "P" SERIES ( T i l )
YES
HZ
CHECK FOR;
- FAULTY, WORN OR CRACKED SPARK PLUG(S)
- PLUG FOULING DUE TO ENGINE MECHANICAL FAULT.
IF SPARK PLUGS CHECK OUT OK, SEE "CUTS OUT,
MISSES" IN SYMPTOMS SECTION B.
YES
HZ
REPLACE THE SPARK PLUG FOR THE LEAD WHICH
WAS JUMPERED TO GROUND. IF MISFIRE IS STILL
PRESENT, START MISFIRE TEST AGAIN AT STEP # 1 .
NO
X
REPLACE
FAULTY WIRE(S)
1
NO
X
FAULTY IGNITION COIL. ALSO CHECK FOR .
FAULTY PLUG WIRE CONNECTIONS AND
WIRE NIPPLES FOR CARBON TRACKING.
1
NO
X
FAULTY DIS
MODULE
^ C A U T I O N : W h e n handling secondary spark plug leads w i t h engine r u n n i n g ,
insulated pliers must be used and care exercised t o prevent a possible electrical shock.
CLEAR CODES AND CONFIRM " C L O S E D L O O P " OPERATION AND NO "SERVICE ENGINE S O O N " LIGHT.
6-10-86
7S 3574-6E