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Home >> Isuzu >> 1998 >> Trooper LS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Testing >> Trouble Shooting - Hombre 2.2L >> Engine Cranks But Will Not Start >> Fuel System
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Fuel System

  1. Perform On-Board Diagnostic II (OBD-II) System Check. See ON-BOARD DIAGNOSTIC (OBD-II) SYSTEM CHECK in TESTS W/CODES - INTRODUCTION article. After performing OBD-II system check, go to next step.
  2. Ensure fuel pump relay fuse ECM B (20-amp) is okay. If fuse is okay, go to next step. If fuse is faulty, go to step 20).
  3. Install Tech 2 scan tool. Turn ignition on. Using scan tool, command fuel pump on. Fuel pump should operate for about 2 seconds. If fuel pump operates as specified, diagnose fuel system. See FUEL SYSTEM DIAGNOSIS  . If fuel pump does not operate, go to next step.
  4. Remove fuel pump relay. Using a fused jumper wire, jumper fuel pump relay feed terminal (Dark Green/White wire) and fuel pump relay ignition feed terminal. See WIRING DIAGRAMS article. If fuel pump operates, go to next step. If fuel pump does not operate, go to step 6).
  5. Using a test light connected to ground, probe fuel pump relay control terminal (Dark Green/white wire). See WIRING DIAGRAMS article. Using scan tool, command fuel pump on. If test light illuminates, go to step 7). If test light does not illuminate, go to step 8).
  6. Using a test light connected to ground, probe fuel pump relay ignition feed terminal. See WIRING DIAGRAMS article. If test light illuminates, go to step 9). If test light does not illuminate, go to step 10).
  7. Using a test light connected to battery voltage, probe fuel pump relay ground terminal (Black wire). See WIRING DIAGRAMS article. If test light illuminates, go to step 11). If test light does not illuminate, go to step 12).
  8. Check for an open or short to ground in fuel pump relay control circuit (Dark Green/White wire). Repair as necessary. After repairs, go to step 25). If circuit is okay, go to step 13).
  9. Reinstall fuel pump relay. Disconnect fuel pump connector at fuel pump. Using a test light connected to ground, probe Gray wire at fuel pump connector feed terminal (body side). Using scan tool, command fuel pump on. If test light illuminates, go to step 14). If test light does not illuminate, go to step 15).
  10. Repair open in ignition feed circuit to fuel pump relay. See WIRING DIAGRAMS article. After repairs, go to step 25).
  11. Replace fuel pump relay. After repairs, go to step 25).
  12. Repair open in fuel pump relay ground circuit (Black wire). After repairs, go to step 25).
  13. Check connections and terminals to PCM. Repair as necessary. After repairs, go to step 25). If connections and terminals are okay, go to step 16).
  14. Using a test light connected to battery voltage, probe Black wire at fuel pump terminal (body side). If test light glows, go to step 17). If test light does not glow, go to step 18).
  15. Repair open in fuel pump feed circuit (Gray wire). After repairs, go to step 25).
  16. Replace PCM. Program PCM. After replacing PCM, go to step 25).
  17. Check for an open in fuel pump feed circuit (Gray wire) and ground circuit (Black wire). Repair as necessary. After repairs, go to step 25). If circuit is okay, go to step 19).
  18. Repair open in fuel pump ground circuit (Black wire). After repairs, go to step 25).
  19. Replace fuel pump. After repairs, go to step 25).
  20. Disconnect fuel pump connector at fuel pump. Remove fuel pump relay. Turn ignition off. Using a test light connected to battery voltage, probe fuel pump feed terminal (Gray wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 22).
  21. Repair short to ground in fuel pump feed circuit (Gray wire). After repairs, go to step 25).
  22. Using a test light connected to battery voltage, probe fuel pump relay ignition feed terminal. See WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 24).
  23. Repair short to ground in fuel pump relay ignition feed circuit. See WIRING DIAGRAMS article. After repairs, go to step 25).
  24. Check for short to ground in fuel pump feed circuit (Gray wire). Repair as necessary. After repairs, go to next step. If circuit is okay, go to step 19).
  25. Using scan tool, clear DTC(s). Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts but dies, go to step 2).
  26. Warm engine to operating temperature. Check for DTCs. If DTCs are present, go to appropriate TESTS W/CODES - INTRODUCTION article. If DTC(s) are not present, system is okay.
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