C 1500 Truck 2WD V6-4.3L VIN W (1996)
An inoperative fuel pump relay can result in long cranking times. The time necessary for the oil pressure to reach the pressure required in order to close
the oil pressure switch and supply the necessary current for the fuel pump causes the extended crank period. If the fuel pump relay circuit checks out OK,
refer to Fuel System Diagnosis. See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Component Tests and General
Diagnostics/Fuel System Diagnosis
Excessive fuel may also cause long cranking times which is accompanied by the following conditions:
1. A start that is not as fast as normal
2. A puff of black smoke at the tailpipe.
An improperly connected or faulty Evaporative Emissions (EVAP) canister control valve can cause this problem. Disconnect the EVAP purge hose from
the EVAP canister control valve in order to diagnose. Refer to EVAP Control System Diagnosis. See: Powertrain Management/Computers and Control
Systems/Testing and Inspection/Component Tests and General Diagnostics/EVAP Control System Diagnosis
One or more leaking poppet nozzles may also extend the cranking time. Perform the Poppet Nozzle Test, in the Injector Balance Test Table. Refer to
Fuel Injector Balance Test. See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Component Tests and General
Diagnostics/Fuel Injector Balance Test Procedure
TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
2. This step checks for the correct operation of the fuel pump.
3. This step checks the operation of the fuel pump by supplying 12 volts to the fuel pump control circuit.
5. This step checks the battery feed circuit to the fuel pump relay.
10. This step checks for the proper operation of the fuel pump relay.
