lemon-mirror:
Home >> Chevrolet >> 1997 >> Venture LS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Basic Engine Testing >> No-Start Diagnosis >> No Start - Engine Cranks Okay >> Ignition System

Ignition System

  1. Perform On-Board Diagnostic (OBD) System Check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . After performing OBD system check, go to next step.
  2. Install Tech 1 scan tool. Using scan tool, select FAILED SINCE CODE CLEAR function. If Diagnostic Trouble Code (DTC) P0101, P0123, P0601/P0602, P1200, P1374, P1626 or P1629 is present, diagnose DTC. See the TESTS W/CODES article. If DTC(s) are not present, go to next step.
  3. Turn ignition on with engine off. Using scan tool, monitor Manifold Absolute Pressure (MAP) sensor. If MAP sensor value is less than 65 kPa, go to step 27). If MAP sensor value is more than 65 kPa, go to next step.
  4. Turn ignition off. Disconnect MAP sensor connector. Attempt to start engine. If engine starts and continues to run, go to step 27). If engine does not start, go to next step.
  5. Turn ignition off. Reconnect MAP sensor connector. Install fuel pressure gauge. Turn ignition on and observe fuel pressure. Fuel pressure should be 41-47 psi (2.9-3.3 kg/cm2 ). If fuel pressure is as specified, go to step 7). If fuel pressure is not as specified, go to next step.
  6. If fuel pressure is present, but not as specified, diagnose fuel system. See BASIC FUEL SYSTEM CHECKS  . If fuel pressure is not present, go to FUEL SYSTEM.
  7. Turn ignition off. Disconnect 10-pin fuel injector/engine harness connector. Using a test light connected to battery voltage, probe each injector driver circuit while cranking engine. If test light flashes, go to next step. If test light does not flash, go to step 9).
  8. Remove fuel injection fuse from underhood fuse block. Install Spark Tester (J-26792) to cylinder No. 2, 4 and 6 (one at a time). Connect the spark plug wire of companion cylinder to ground. Crank engine and observe spark tester. If spark is present, go to step 19). If spark is not present, go to step 11).
  9. Check fuel injector feed circuit fuse. If fuse is faulty, check for an open or shorted circuit, or shorted injector. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If circuit and injector are okay, go to next step.
  10. Check for open in fuel injector feed circuit or ignition main relay feed circuits. Check for open in ignition main relay ground circuit. Check for stuck open ignition main relay or corroded contacts. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If circuits or relay are okay, testing is complete.
  11. Check fuse to Ignition Control Module (ICM) ignition feed circuit. If fuse is faulty, check for short between ICM feed circuit and engine ground, module ground, IC control circuit or reference low circuit. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If fuse is okay, go to next step.
  12. Check for open in ICM feed and ground circuits. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If circuits are okay, go to next step.
  13. Disconnect 7X Crankshaft Position (CKP) sensor connector from ICM. Connect DVOM between CKP sensor harness connector terminals. Set DVOM to 2-volt AC scale. Crank engine and observe DVOM. DVOM should read about 2-volts AC. If voltage is as specified, go to step 15). If voltage is not as specified, go to next step.
  14. Turn ignition off. Check 7X CKP sensor circuit for open or short to voltage or ground. Check for poor 7X CKP sensor connection. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If circuit is okay, go to step 28).
  15. Check for poor ICM connection. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If connection is okay, go to next step.
  16. Remove and inspect coil that did not produce a spark. Check for cracks or carbon tracking. Replace as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If coil(s) are okay, go to next step.
  17. Check secondary resistance to ignition coil that did not produce a spark. Resistance should be 5000-7000 ohms. If resistance is not as specified, replace ignition coil. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If coil resistance is as specified, go to next step.
  18. Connect a test light across affected ICM primary terminals. Crank engine and observe test light. If test light flashes while cranking engine, go to step 29). If test light does not flash, go to step 30).
  19. Check cylinders No. 2, 4 and 6 spark plug wires. Check for carbon tracking or damaged insulation. Replace as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If wire(s) are okay, go to next step.
  20. Check spark plug wire resistance of cylinders No. 2, 4 and 6. Resistance should be 7000 ohms. If resistance is not as specified, replace wire(s). After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If wire(s) are okay, go to next step.
  21. Remove spark plugs from cylinders No. 2, 4 and 6. Check spark plug electrodes for excessive fouling. If excessive fouling is present, go to step 26). If excessive fouling is not present, go to next step.
  22. Check cylinders No. 1, 3 and 5 spark plug wires. Check for carbon tracking or damaged insulation. Replace as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If wire(s) are okay, go to next step.
  23. Check spark plug wire resistance of cylinders No. 1, 3 and 5. Resistance should be 7000 ohms. If resistance is not as specified, replace wire(s). After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If wire(s) are okay, go to next step.
  24. Remove spark plugs from cylinders No. 1, 3 and 5. Check spark plug electrodes for excessive fouling. If excessive fouling is present, go to step 26). If excessive fouling is not present, go to next step.
  25. Test fuel for contamination. If fuel is contaminated, clean fuel system. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If fuel is not contaminated, check for poor or damaged PCM connector, for faulty engine coolant temperature sensor, or mass air flow miscalculated due to faulty throttle position sensor or manifold absolute pressure sensor. See the SYSTEM/COMPONENT TESTS article.
  26. Check for engine mechanical problem. Check for bent push rods, faulty camshaft, leaking or sticky valves or rings, excessive valve deposits, loose or worn rocker arms, weak valve springs, incorrect valve timing or leaking head gasket. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  27. Replace MAP sensor. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  28. Replace 7X CKP sensor. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  29. Replace ignition coil(s) associated with cylinder that did not produce a spark. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  30. Replace ICM. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  31. Replace PCM. Perform PCM relearn procedures. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
· About lemon-mirror