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Home >> GMC >> 1998 >> Forward Control 6.5 F >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Engine Testing - 6.5L Turbo Diesel >> No Start Diagnosis >> No Start - Engine Cranks Okay >> Basic System Check
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Basic System Check

  1. Perform On-Board Diagnostic (OBD) System Check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in TESTS W/CODES - 6.5L TURBO DIESEL article. After performing OBD system check, go to next step.
  2. Check battery condition. If battery is okay, go to next step. If battery condition is not okay, go to step 23).
  3. Check fuel level in tank. If fuel level is okay, go to next step. If fuel level is not okay, go to step 23).
  4. Check quality of fuel. If fuel quality is okay, go to next step. If fuel quality is not okay, go to step 23).
  5. Check glow plug operation. If glow plug operation is okay, go to next step. If glow plug operation is not okay, go to step 23).
  6. Check for proper cranking speed. If cranking speed is okay, go to next step. If cranking speed is not okay, go to step 23).
  7. Check for restriction in fuel return system. If restriction is not present, go to next step. If return line is restricted, go to step 23).
  8. Check injection pump ground wire located on top of injection pump. If ground is okay, go to next step. If ground is not okay, go to step 23).
  9. Turn ignition on. Observe Malfunction Indicator Light (MIL). If MIL illuminates, go to step 10). If MIL does not illuminate, go to MALFUNCTION INDICATOR LIGHT (MIL) in TESTS W/CODES - 6.5L TURBO DIESEL article.
  10. Install scan tool. Using scan tool, check for any data. If data is displayed, go to next step. If data is not displayed, go to DLC DIAGNOSIS OR NO SCAN TOOL DATA in TESTS W/CODES - 6.5L TURBO DIESEL article.
  11. Loosen injector line at injector. Crank engine. If fuel comes out of fuel line, go to step 17). If fuel is not coming out of fuel line, go to next step. Repeat procedure for all injectors.
  12. Disconnect optical/fuel temperature sensor. Attempt to start engine. If engine does not start, go to next step. If engine starts, go to step 16).
  13. Reconnect optical/fuel temperature sensor. Disconnect fuel solenoid driver at fuel injection pump. While cranking engine, check voltage between ground and fuel injector control circuit at harness connector. See WIRING DIAGRAMS - 6.5L TURBO DIESEL article. Voltage should be 1.2 volts or greater. If voltage is as specified, go to next step. If voltage is not as specified, go to step 18).
  14. With fuel solenoid driver still disconnected, probe solenoid ground circuit with test light connected to battery voltage at harness connector. See WIRING DIAGRAMS - 6.5L TURBO DIESEL article. If test light illuminates, go to next step. If test light does not illuminate, go to step 19).
  15. Turn ignition on with engine off. Ensure fuel solenoid driver is still disconnected. Using test light connected to ground, probe ignition feed circuit at fuel solenoid harness connector. See WIRING DIAGRAMS - 6.5L TURBO DIESEL article. If test light illuminates, go to next step. If test light does not illuminate, go to step 21).
  16. Replace fuel injection pump. After repairs, go to step 25).
  17. Injection system is okay. See TESTS W/O CODES - 6.5L TURBO DIESEL article.
  18. Check for open or short in fuel injector control circuit between fuel solenoid driver and PCM. Repair as necessary. After repairs, go to step 22). If circuit is okay, go to step 20).
  19. Check closure signal ground circuit for open between fuel solenoid driver and PCM. Repair as necessary. After repairs, go to step 22). If circuit is okay, go to next step.
  20. Check for poor connections at fuel solenoid driver and PCM connectors. Repair as necessary. After repairs, go to step 22). If connectors are okay, go to step 24).
  21. Repair open in ignition feed circuit. After repairs, go to step 25).
  22. Repair circuit as necessary. After repairs, go to step 25).
  23. Repair as necessary. After repairs, go to step 25).
  24. Replace PCM. Perform PCM relearn procedures. After repairs, go to next step.
  25. Using scan tool, select DTC, CLEAR INFO function. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and stalls/dies, go to step 2).
  26. Warm engine to normal operating temperature. Using scan tool, select DTC, FAILED THIS IGN function. If any DTC(s) is present, go to next step.
  27. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any other DTC(s) is present that has not been diagnosed, diagnose DTC(s). See TESTS W/CODES - 6.5L TURBO DIESEL article. If DTC(s) is not present, system is okay.
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