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1J-94 FUEL SYSTEMS
C4 SYSTEM TESTS AND TROUBLE CODE DIAGNOSIS
Chart 1—C4 System Operational Test
1. INSTALL TEST BULB, TURN IGNITION SWITCH ON, GROUND TROUBLE CODE "TEST" LEAD, OBSERVECODE.
2. PLACE TRANSMISSION IN NEUTRAL AND SET PARKING BRAKE.
3. DISCONNECT PURGE HOSE FROM CANISTER AND PLUG. DISCONNECT BOWL VENT HOSE AT CARBURETOR.
4. CONNECT TACHOMETER. (DISTRIBUTOR SIDE OF TACH FILTER, IF USED.)
5. DISCONNECT MIXTURE CONTROL (MC) SOLENOID AND GROUND DWELL LEAD.
6. START ENGINE.
7. RUN ENGINE AT 3,000 RPM AND, WITH THROTTLE CONSTANT, RECONNECT MC SOLENOID.
8. OBSERVE RPM.
LESS THAN 100 RPM DROP
CHECK MC SOL. AND MAIN
METERING CIRCUIT. SEE E2SE
CARB., CHAPTER U.
FIXED 5°-10°
| FIXED 10°-50°n
SEE CHART 2
SEE CHART 3
T
MORE THAN 100 RPM DROP
•
REMOVE GROUND FROM DWELL LEAD.
• CONNECT DWELL METER TO MC SOLENOID DWELL LEAD
(USE 6 CYL. SCALE).
•
SET CARB. ON HIGH STEP OF FAST IDLE CAM AND RUN FOR
THREE MINUTES OR UNTIL DWELL STARTS TO VARY, WHICH
EVER HAPPENS FIRST.
• RETURN ENGINE TO IDLE AND OBSERVE DWELL* *
FIXED 50°-55°
SEECHART4
VARYING
CHECK DWELL AT 3,000 RPM
I
BETWEEN 10°-50°
T
NOT BETWEEN 10°-50°
REFER TO E2SE CARBURETOR
IDLE MIXTURE ADJUSTMENT
• C4 SYSTEM OPERATING NORMALLY
• CLEAR LONG TERM MEMORY
IF TEST BULB IS NOT ILLUMINATED, SEE CHART 6.
••OXYGEN SENSOR TEMPERATURE MAY COOL AT IDLE CAUSING THE DWELL TO CHANGE FROM VARYING TO
A FIXED INDICATION BETWEEN 100-50°. IF THIS HAPPENS, RUN THE ENGINE AT FAST IDLE TO HEAT THE
SENSOR.
90769A
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Troubleshooting
