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Home >> Isuzu >> 1992 >> Trooper S, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Testing >> Fuel System >> Fuel Pressure & Fuel Pump Relay Test >> Fuel Pump Relay (3.1L Pickup & Rodeo)

Fuel Pump Relay (3.1L Pickup & Rodeo)

  1. Fuel pump relay is powered through the ECM. During cranking, ECM will power fuel pump for 2 seconds or until ECM receives ignition reference signals. If engine does not start within 2 seconds after key is turned on, ECM turns off power to fuel pump.
    NOTE: To test fuel pump relay circuit, see appropriate CHART A-7, FUEL SYSTEM PRESSURE TEST under DIAGNOSTIC CHARTS.
  2. If fuel pump relay fails (setting trouble Code 54), oil pressure switch provides back-up circuit to run fuel pump. Oil pressure switch circuit closes when oil pressure is greater than 4 psi (.28 kg/cm2 ) and operates fuel pump back-up relay.
  3. Fuel pump relay and back-up relay are located in fuse/relay box, in engine compartment. Also see Code 54 in appropriate TESTS W/CODES article in the ENGINE PERFORMANCE Section.