LEMON Manuals: Even more car manuals for everyone
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 1)

Fuel System Electrical Circuit (VIN 1)

  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. If Diagnostic Trouble Code (DTC) P0230 or P1667 is present, diagnose DTC(s). See TESTS W/CODES article. If DTC(s) is not present, go to next step.
  3. Turn ignition off. Install fuel pressure gauge. Using a 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 as specified, go to next step. If fuel pressure is not as specified, go to step 5).
  4. Start engine. Using a scan tool, select FP SPEED OUTPUT CONTROL function. Observe fuel pressure gauge while commanding fuel pump speed between normal and high with scan tool. Fuel pressure should slightly increase when high fuel pump speed is selected. If fuel pressure increases, system is okay. If fuel pressure does not change, go to step 31).
  5. Turn ignition off. Disconnect fuel pump control module connector. Using a fused jumper wire, jumper fuel pump feed circuit of fuel pump control module connector to battery voltage. See WIRING DIAGRAMS article. Connect a second jumper wire between fuel pump ground circuit of fuel pump control module connector and ground. See WIRING DIAGRAMS article. Observe fuel pressure gauge. 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 26).
  6. Disconnect jumpers from fuel pump control module connector. Connect test light between fuel pump control module feed circuit of fuel pump control module connector and ground. See WIRING DIAGRAMS article. Turn ignition on. Using scan tool output controls function, command fuel pump relay on. If test light illuminates, go to next step. If test light does not illuminate, go to step 13).
  7. Using a test light connected to battery voltage, probe fuel pump control module connector ground circuit. See WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 25).
  8. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using a test light connected to battery voltage, probe PCM connector fuel pump PWM control circuit. See WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 10).
  9. Locate and repair short to ground in fuel pump PWM control circuit. After repairs, go to step 39).
  10. Turn ignition off. Reconnect PCM connector. Turn ignition on. Connect DVOM between fuel pump PWM control circuit and ground circuit of fuel pump control module connector. See WIRING DIAGRAMS article. Using scan tool output controls function, command fuel pump relay on and off. DVOM should read greater than 8 volts while fuel pump relay is commanded on. If voltage is as specified, go to next step. If voltage is not as specified, go to step 38).
  11. Turn ignition off. Reconnect fuel pump control module connector. Turn ignition on. Using test light, backprobe between fuel pump control module connector fuel pump feed circuit and fuel pump ground circuit. See WIRING DIAGRAMS article. Using scan tool output controls function, command fuel pump relay on and off while observing test light. Test light should illuminate when fuel pump relay is commanded on. If test light illuminates, go to next step. If test light does not illuminate, go to step 34).
  12. Check for poor terminal connection at fuel pump control module. Repair connection as necessary. After repairs, go to step 39). If connection is okay, check PCM and connectors for improper mating, check for rubbed through wire insulation or a wire broken inside insulation.
  13. Turn ignition off. Remove fuel pump relay. Turn ignition on. 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 next step. If test light does not illuminate, go to step 19).
  14. Connect test light between feed circuit and ground circuit of fuel pump relay connector. See WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 20).
  15. Connect test light between control circuit and ground circuit of fuel pump relay connector. See WIRING DIAGRAMS article. Using scan tool output controls function, command fuel pump relay on while observing test light. If test light illuminates when fuel pump relay is on, go to next step. If test light does not illuminate, go to step 21).
  16. Connect jumper wire between fuel pump relay connector feed circuit and fuel pump control module connector feed circuit. See WIRING DIAGRAMS article. Using a test light connected to ground, probe fuel pump control module connector fuel pump control module feed circuit. See WIRING DIAGRAMS article. If test light does not illuminate, go to step 24). If test light illuminates, go to next step.
  17. Check for poor terminal connection at fuel pump relay. Repair or replace as necessary. After repairs, go to step 39). If terminal connection is okay, go to next step.
  18. Replace fuel pump relay. After replacing fuel pump relay, go to step 39).
  19. Locate and repair open in fuel pump relay feed circuit. After repairs, go to step 39).
  20. Locate and repair open in fuel pump relay ground circuit. After repairs, go to step 39).
  21. Turn ignition off. Disconnect 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 next step. If test light does not illuminate, go to step 23).
  22. Locate and repair short to ground in fuel pump relay control circuit. After repairs, go to step 39).
  23. Check fuel pump relay control circuit for poor connection or open circuit between fuel pump relay and PCM. Repair as necessary. After repairs, go to step 39). If connection and circuit are okay, go to step 38).
  24. Locate and repair open in fuel pump control module feed circuit. After repairs, go to step 39).
  25. Locate and repair open in fuel pump control module ground circuit. After repairs, go to step 39).
  26. Remove fuel filler cap and listen for fuel pump operation. If fuel pump is running, diagnose fuel system. See BASIC FUEL SYSTEM CHECKS  . If fuel pump is not running, go to next step.
  27. Using fused jumper wires, connect battery voltage to fuel pump feed circuit, and ground to fuel pump ground circuit. See WIRING DIAGRAMS article. Raise and support vehicle. Disconnect fuel sending unit connector at fuel tank. Connect test light between fuel sending unit connector fuel pump feed circuit and fuel pump ground circuit. See WIRING DIAGRAMS article. If test light illuminates, go to step 36). If test light does not illuminate, go to next step.
  28. Using a test light connected to ground, probe fuel sending unit connector fuel pump feed circuit. See WIRING DIAGRAMS article. If test light does not illuminate, go to next step. If test light illuminates, go to step 30).
  29. Locate and repair open in fuel pump feed circuit. After repairs, go to step 39).
  30. Locate and repair open in fuel pump ground circuit. After repairs, go to step 39).
  31. Using test light, backprobe between fuel pump control module fuel pump PWM control circuit and fuel pump control module feed circuit. See WIRING DIAGRAMS article. Start and idle engine. Using a scan tool, select FP SPEED OUTPUT CONTROL function. Observe test light while switching scan tool between normal and high. Test light should illuminate when normal is selected, and then turn off when high is selected. If test light illuminates as indicated, go to next step. If test light does not illuminate as indicated, go to step 33).
  32. Using DVOM, backprobe between fuel pump control module fuel pump ground circuit and fuel pump feed circuit. see WIRING DIAGRAMS article. Start and idle engine. Using a scan tool, select FP SPEED OUTPUT CONTROL function. Observe DVOM voltage reading while switching scan tool between normal and high speed. On normal speed, DVOM should read about 8 volts. On high speed, DVOM should read battery voltage. If voltage readings are as specified, go to step 36). If voltage readings are not as specified, go to step 34).
  33. Check fuel pump PWM control circuit for poor terminal connection, or an open or short to voltage between fuel pump control module and PCM. Repair terminal or circuit as necessary. After repairs, go to step 39). If circuit or terminal is okay, go to step 38).
  34. Check for poor terminal connection at fuel pump control module. Repair or replace as necessary. After repairs, go to step 39). If terminal connection is okay, go to next step.
  35. Replace fuel pump control module. After replacing fuel pump control module, go to step 39).
  36. Check for poor terminal connection at fuel pump. Repair or replace as necessary. After repairs, go to step 39). If terminal connection is okay, go to next step.
  37. Replace fuel pump. After replacing fuel pump, go to step 39).
  38. Replace PCM. Ensure PCM relearn procedure is performed. After replacing PCM, go to next step.
  39. Turn ignition on. Using a 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 as specified, go to next step. If fuel pressure is not as specified, go to step 5).
  40. Start and idle engine. Using scan tool, select FP SPEED CONTROL OUTPUT function. Observe fuel pressure gauge while commanding fuel pump speed between normal and high with scan tool. Fuel pressure should slightly increase when high speed is selected. If fuel pressure does not slightly increase, go to step 31). If fuel pressure increases as specified, system is okay.
scientia non olet · About LEMON Manuals