Pontiac Fiero 1988 Service Manual page 472

DRIVEABILITY AND EMISSIONS - FUEL INJECTION (TBI) 6E2-A-17
CHART A-3
(Page 2 of 3)
ENGINE CRANKS BUT WON'T RUN
2.5L"P" SERIES (TBI)
©
• CRANK
ENG
AND CHECK FOR SPARK WITH
ST-125 ON 1
& 2 0 R 3 & 4 .
• CHECK ONE WIRE AT A TIME, LEAVE THE OTHER WIRES
CONNECTED TO THE SPARK PLUGS DURING CRANKING.
©
SPARK ON ONE WIRE
• NOTE WHICH WIRE HAS NO SPARK.
• IGN OFF.
9 REMOVE IGN COILS.
IS THERE EVIDENCE OF CARBON
TRACKING ARCING OR FAULTY
CONN. BETWEEN COIL AND
MODULE?
©
NO
1
• SWITCH COIL
POSITIONS ON
MODULE ANDRE-
INSTALL.
• CHECK FOR SPARK
WITH ST-125 ON
PREVIOUSLY NOTED
WIRE WITH NO
SPARK.
IS SPARK PRESENT
NOW?
YES
REPLACE
AFFECTED
COIL.
©
NO
REPLACE IGN
MODULE.
YES
m
REPLACE COIL
ORIGINALLY CON-
NECTED TO THIS
SPARK PLUG WIRE.
NO SPARK SPARK ON BOTH WIRES
• DISCONNECT 2 WIRE
CONNECTOR AT IGN
MODULE.
• IGN. "ON".
• PROBE IGN. CKT WITH A
TEST LIGHT TO GND.
IS THE TEST LIGHT "ON"?
©
E
• IGN OFF.
• DISCONNECT 6 WAY CONN. AT
IGN MODULE.
• IGN ON.
• REPEATEDLY TOUCH CKT 430
WITH A TEST LIGHT TO 12V
WHILE OBSERVING CRANK RPM.
IS RPM INDICATED?
YES
1
• PROBE GND CKT 450
WITH A TEST LIGHT
TO 12 V.
IS TEST LIGHT "ON"?
NO
IE
YES
1
OPEN IGN.
CKT
FAULTY IGN
MODULE.
NO
m
OPEN OR SHORT
TO GND. CKT 430,
OR FAULTY ECM.
YES
NO
• REMOVE DIRECT IGN. SYSTEM ASSEMBLY FROM
ENGINE.
• REMOVE SENSOR FROM MODULE AND
CONNECT DVOM BETWEEN SENSOR TERMINALS.
• WITH METER IN OHMS 2K POSITION,
RESISTANCE SHOULD READ BETWEEN 800 AND
900 OHMS.
• REST A FLAT STEEL TOOL AGAINST TIP OF
SENSOR AND VERIFY THAT SENSOR IS STILL
MAGNETIZED.
• INSPECT SENSOR FOR SPRUNG TERMINALS.
r
OPEN CKT 450.
TESTS OK
E
TESTS NOT OK
FAULTY IGNITION
MODULE
FAULTY SENSOR
6-12-86
*7S3231-6E