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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 (4.3L - Sierra & SILVERADO) >> Diagnostic Procedure

Diagnostic Procedure

  1. Did you perform a Diagnostic System Check-Engine Controls? If yes, go to next step. If no, perform DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article.
  2. Turn ON the ignition, with the engine OFF. With a scan tool, observe the DTC information. Does the scan tool display DTCs P0230, P0335, P0336, P0601, P0602, P0604, P1626, P1631 or P1683? If yes, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article. If no, go to next step.
    3. NOTE: Ensure the following fuses are not open before proceeding with this test.
  3. Turn ON the ignition, with the engine OFF. Probe both sides of fuses ECM 1, INJ A and INJ B. Does the test light illuminate on both sides of all the fuses listed? If yes, go to next step. If no, go IGNITION RELAY DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS article.
  4. Attempt to start the engine. With a scan tool, monitor the Engine Speed parameter while the engine is cranking. Does the engine speed increment? If yes, go to next step. If no, go to DISTRIBUTOR IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS article.
  5. With a scan tool, command the fuel pump ON. Does the fuel pump turn ON? If yes, go to next step. If no, go to FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS article.
  6. Turn OFF the ignition. Install the J 34730-1A Fuel Pressure Gauge. Turn ON the ignition, with the engine OFF. With a scan tool, command the fuel pump ON. Is the fuel pressure 60-66 psi (414-455 kPa)? If yes, go to next step. If no, go to FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS article.
  7. Turn OFF the ignition. Disconnect a spark plug wire. Install the J 26792 Spark Tester to the spark plug wire. Attempt to start the engine. Does the spark tester spark? If yes, go to next step. If no, go to DISTRIBUTOR IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS article.
  8. Inspect for the following conditions:
    • Collapsed air intake duct.
    • Restricted air filter element.
    • Spark plugs for being gas or coolant fouled. If the spark plugs are fouled, determine what caused the condition.
    • Engine mechanical condition (worn timing chain, gears and low compression).
    • Restricted exhaust system.
    • The Engine Coolant Temperature (ECT) sensor is not close to the actual engine temperature. See DTC P0117: ECT SENSOR CIRCUIT - LOW VOLTAGE or DTC P0118: ECT SENSOR CIRCUIT - HIGH VOLTAGE under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article.
    • Compare Manifold Absolute Pressure/Barometric Pressure (MAP/BARO) parameters to another vehicle. The parameters should be close in value. See DTC P0106: MAP SYSTEM PERFORMANCE under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article.
    • The throttle position (TP) sensor for being stuck in range. See DTC P0121: TP SENSOR PERFORMANCE under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article.

    Did you find and correct the condition? If yes, go to next step. If no, fault is intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

  9. With a scan tool, clear the DTCs. Attempt to start the engine. Does the engine start and continue to operate? If yes, go to next step. If no, go to step  2.
  10. Idle the engine. Allow the engine to reach operating temperature. With a scan tool, observe the DTC information. Are any DTCs displayed? If yes, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article. If no, go to next step.
  11. With a scan tool, review the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article. If no, system is okay.
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