Chart A-3 - Engine Cranks But Will Not Run: Notes
NOTE:
Test numbers refer to numbers on diagnostic chart.
- When ignition is turned on, CHECK ENGINE light should come on, indicating battery voltage and ignition voltage are being supplied to ECM. If NO ALDL data (trouble codes) are displayed on scan tester, this may be due to ECM problem. See appropriate chart in SELF-DIAGNOSTICS article to diagnose CHECK ENGINE light. If TPS voltage is more than 2.5 volts, engine may be in "clear flood mode", which will cause starting problems. Engine will not start without ignition reference signals. Scan tester should indicate engine speed (RPM) during cranking.
- If engine speed is indicated during cranking, ignition module is receiving a crank signal. No spark in this test indicates ignition module is not triggering coil, or there is a secondary ignition problem.
- Test light should flash, indicating ECM is controlling injectors. Test light brightness is not important.
- This test checks ignition module reference signal, wiring and ECM. By touching and removing test light to battery voltage on circuit No. 430, ignition reference signal should be generated. If engine speed is indicated, ECM and wiring are okay.
- Checks for ignition voltage at injector harness connector. Disconnect H4 (Gray, 12-pin) connector before probing terminal No. 12. Reconnect connector after test.
- Checks for open in circuit No. 467 or 468 from connector to ECM. Ensure injector harness is connected.
- Disconnect ECM C-D connector, and check injector jumper circuits with a DVOM.