Jeep 1987 Wrangler Workshop Manual page 1611

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THROTTLE BODY FUEL INJECTION SYSTEM
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2.0L ENGINE
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COMPONENT DIAGNOSIS
C O N D I T I O N P O S S I B L E C A U S E C O R R E C T I O N
FUEL PUMP OPERATES Fuel pump relay has short circuit to Check Pin A5 for a short circuit to
CONTINUOUSLY. ground. ground with the key off and fuel ground.
pump relay disconnected.
Repair the wire harness short circuit.
Disconnect the ECU from the wire
harness.
If the pump stops, check the ECU
with MS 1700 tester.
Disconnect the fuel pump relay and
check for a short circuit.
Replace the relay.
Test the ECU with MS 1700 tester.
FUEL PUMP WILL NOT Open circuit.
Connect a jumper wire across the
OPERATE FOR ONE fuel pump relay.
SECOND WITH THE
fuel pump relay.
IGNITION SWITCH ON.
If the pump operates, check for
battery voltage at the relay. Check
the continuity between the relay and
Pin A5 at the ECU. Repair the wire
harness as necessary. Replace the
fuel pump relay. Test the ECU with
MS 1700 tester.
Test for continuity between the fuel
pump and the relay contacts.
Check the pump ground circuit.
Repair the harness as necessary.
Fuel pump ballast resistor defective.
Replace the fuel pump ballast
resistor.
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85430B-3