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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Basic Diagnostic Procedures >> No-Start Diagnosis >> No-Start - Engine Cranks Okay (8.1L) >> Diagnostic Procedure

Diagnostic Procedure

  1. Perform OBD system check. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 8.1L "C", "G" & "K" SERIES TRUCKS article. After performing diagnostic system check, go to next step.
  2. Turn ignition on, with engine OFF. Check for DTCs. If DTC P0230, P0335, P0336, P0601, P0602, P0604, P0606, P1626, P1631 or P1683 is set, perform appropriate diagnostic procedure for DTC set. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 8.1L "C", "G" & "K" SERIES TRUCKS article. If no DTCs are set, go to next step.
    3. NOTE: Ensure ECM 1, ETC, INJ A and INJ B fuses are not open, before proceeding with this test.
  3. Turn ignition on, with engine OFF. Using test light connected to ground, probe both sides of ECM 1, ETC, INJ A and INJ B fuses. If test light illuminates on both sides of all fuses, go to next step. If test light does not illuminate on both sides of all fuses, go to IGNITION RELAY DIAGNOSIS (8.1L) under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  4. Turn ignition off. Disconnect a spark plug wire. Install Spark Tester (J 26792) to spark plug wire. Attempt to start engine. If spark tester indicates a good spark, go to next step. If spark tester does not indicate a good spark, go to ELECTRONIC IGNITION SYSTEM DIAGNOSIS (8.1L) under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  5. Using scan tool, command fuel pump ON. If fuel pump operates, go to next step. If fuel pump does not operate, go to FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  6. Turn ignition off. Install fuel pressure gauge. Turn ignition on, with engine off. Using scan tool, command fuel pump ON. If fuel pressure is 55-62 psi (384-425 kPa) while fuel pump is operating, go to next step. If fuel pressure is not as specified, go to FUEL SYSTEM PRESSURE TEST (4.8L, 5.3L, 6.0L & 8.1L)  under BASIC FUEL SYSTEM CHECKS (GASOLINE).
  7. Turn ignition off. Disconnect an injector connector. Install Injector Test Light (J 34730-405) to injector connector. Attempt to start engine. If test light blinks while engine is cranking, go to next step. If test light does not blink while cranking, go to DTC P0200: FUEL INJECTOR CONTROL CIRCUIT under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 8.1L "C", "G" & "K" SERIES TRUCKS article.
  8. Check for the following conditions:
    • Collapsed air intake duct.
    • Restricted air filter element.
    • Spark plugs for being gas or coolant fouled. If spark plugs are fouled, determine what caused condition.
    • Engine mechanical condition, worn timing chain and gears, low compression, etc.
    • Restricted exhaust system.
    • ECT sensor is NOT close to actual engine temperature.
    • Compare MAP/barometric pressure (BARO) parameters to another vehicle. The parameters should be close in value.

    After repairs, go to next step. If no problems are found, go to DIAGNOSTIC AIDS .

  9. Clear DTCs. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not run, repeat step  2.
  10. Allow engine to idle and reach operating temperature. Check for DTCs. If any DTCs are set, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 8.1L "C", "G" & "K" SERIES TRUCKS article. If no DTCs are set, go to next step.
  11. Using scan tool, review stored information, Capture Info. If scan tool displays any DTCs that have not been diagnosed, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 8.1L "C", "G" & "K" SERIES TRUCKS article. If no DTCs are set, system is okay.
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