LEMON Manuals: Even more car manuals for everyone
Home >> Geo >> 1991 >> Prizm Base, 4D Hatchback, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Testing >> Chart A-5, Cranks But Won't Run, Except GSI >> Notes

Chart A-5, Cranks But Won't Run, Except GSI: Notes

With engine cranking, ECM activates circuit opening relay to operate fuel pump. ECM is located in center of instrument panel, behind console. Circuit opening relay is mounted on bracket attached to ECM. If ECM receives ignition reference pulses, fuel pump will continue to operate. If ECM does not receive ignition reference pulses, fuel pump will be shut off.

NOTE: Test numbers refer to test numbers on diagnostic chart.
  1. Fuel pump should operate when engine is cranking.
  2. This checks for open circuit between fuel pump and circuit opening relay.
  3. This checks for a crank signal to the circuit opening relay.
  4. This checks EFI main relay operation. EFI main relay is located in fuse/relay block on left front side of engine compartment.
  5. This determines if ECM fuel pump driver circuit is defective.
scientia non olet · About LEMON Manuals