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Home >> Buick >> 1998 >> Riviera >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Diagnostic Procedures >> No Start Diagnosis >> No Start - Engine Cranks Okay (VIN K & 1 With C(3)I) >> Fuel System Electrical Circuit (VIN K)

Fuel System Electrical Circuit (VIN K)

  1. Perform On-Board Diagnostic (OBD) System Check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in TESTS W/CODES article. After performing OBD system check, go to next step.
  2. Turn ignition off. Install fuel pressure gauge. Remove fuel pump relay. Using a fused jumper wire, jumper fuel pump feed circuit at fuel pump relay connector to battery voltage. Observe fuel pressure. Fuel pressure should be 48-55 psi (3.4-3.8 kg/cm2 ). If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, go to step 10).
  3. Disconnect jumper wire from fuel pump relay connector. Connect test light between ignition feed circuit and ground circuit of fuel pump relay connector. See WIRING DIAGRAMS article. Turn ignition on and observe test light. If test light illuminates, go to next step. If test light does not illuminate, go to step 9).
  4. Turn ignition off. Connect test light between fuel pump relay control circuit and ground circuit of fuel pump relay connector. See WIRING DIAGRAMS article. Observe test light while turning ignition on. Test light should illuminate for about 2 seconds. If test light illuminates for about 2 seconds, go to step 8). If test light does not illuminate for about 2 seconds, go to next step.
  5. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using a test light connected to battery voltage, probe PCM connector fuel pump relay control circuit. See WIRING DIAGRAMS article. If test light illuminates, go to step 15). If test light does not illuminate, go to next step.
  6. Check for continuity in fuel pump relay control circuit between fuel pump relay and PCM. See WIRING DIAGRAMS article. If circuit is faulty, repair as necessary. After repairs, go to step 21). If circuit is okay, go to next step.
  7. Check fuel pump relay control circuit for poor terminal connection at PCM. See WIRING DIAGRAMS article. If connection is faulty, repair as necessary. After repairs, go to step 21). If circuit is okay, go to step 20).
  8. Check for poor terminal connection at fuel pump relay. See WIRING DIAGRAMS article. If connection is faulty, repair as necessary. After repairs, go to step 21). If circuit is okay, go to step 18).
  9. Using a test light connected to ground, probe fuel pump relay connector ignition feed circuit. See WIRING DIAGRAMS article. If test light illuminates, go to step 17). If test light does not illuminate, go to step 16).
  10. Remove fuel filler cap and listen for fuel pump running. If fuel pump is running, diagnose fuel system. See BASIC FUEL SYSTEM CHECKS  . If fuel pump is not running, go to next step.
  11. Using a fused jumper wire, jumper fuel pump feed circuit at fuel pump relay connector to battery voltage. See WIRING DIAGRAMS article. Raise and support vehicle. Disconnect fuel sending unit connector at fuel tank. Connect test light between fuel pump feed circuit and fuel pump ground circuit of fuel sending unit connector. See WIRING DIAGRAMS article. If test light illuminates, go to step 19). If test light does not illuminate, go to next step.
  12. Using a test light connected to chassis ground, probe fuel sending unit connector fuel pump feed circuit. See WIRING DIAGRAMS article. If test light illuminates, go to step 14). If test light does not illuminate, go to next step.
  13. Locate and repair open in fuel pump feed circuit. After repairs, go to step 21).
  14. Locate and repair open in fuel pump ground circuit. After repairs, go to step 21).
  15. Locate and repair short to ground in fuel pump relay control circuit. After repairs, go to step 21).
  16. Locate and repair open in ignition feed circuit to fuel pump relay. After repairs, go to step 21).
  17. Locate and repair open in ground circuit to fuel pump relay. After repairs, go to step 21).
  18. Replace fuel pump relay. After replacing fuel pump relay, go to step 21).
  19. Replace fuel pump. After replacing fuel pump, go to step 21).
  20. Replace PCM. Perform PCM relearn procedures. After replacing PCM, go to next step.
  21. Turn ignition on. Using scan tool, select FP RELAY OUTPUT CONTROL function. Observe fuel pressure gauge while commanding fuel pump on with scan tool. Fuel pressure should be 48-55 psi (3.4-3.8 kg/cm2 ). If fuel pressure is not as specified, repeat step 2). If fuel pressure is as specified, system is okay.
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