Part 2 of 2

Chart A-5 (2 Of 2):

TEST DESCRIPTION (Cont'd): Numbers below refer to circled numbers on the diagnostic chart.

6. Checks for open in the fuel pump relay ground, CKT 450.

7. Determines if the PCM is in control of the fuel pump relay through CKT 465 (terminal "A").

8. The fuel pump control circuit includes an engine oil pressure switch with a separate set of normally open contacts. The switch closes at about (4.0 lbs) 28.0 kPa of oil pressure and provides a second battery feed path to the fuel pump. If the relay fails, the pump will run, using the battery feed supplied by the closed oil pressure switch.

9. This step checks the oil pressure switch to be sure it provides battery feed to the fuel pump should the pump relay fail. A failed pump relay will result in extended engine crank time because of the time required to build enough oil pressure to close the oil pressure switch and turn "ON" the fuel pump. There may be instances when the relay has failed but the engine will not crank fast enough to build enough oil pressure to close the switch. This or a faulty oil pressure switch can result in "Engine Cranks But Won't Run."