Chart A-3 Engine Cranks But Will Not Run

Chart A-3 - Engine Cranks But Won't Run (Part 1 Of 3):

CHART 1 OF 3

Chart A-3 - Engine Cranks But Won't Run (Part 2 Of 3):

CHART 2 OF 3

Chart A-3 - Engine Cranks But Won't Run (Part 3 Of 3):

CHART 3 OF 3

Ignition Coil Assembly Wiring Circuit:

Circuit Description:
This engine is equipped with a distributorless ignition system called the Electronic Ignition (EI) system. The primary circuit consists of one ignition coil assembly, the ECM, and Crankshaft Position (CKP) sensor as well as the related connecting wires. The secondary circuit consists of the secondary windings of the ignition coil assembly the spark plug cable assemblies and spark plugs.

Chart Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.
1. ^ A MIL (Check Engine) "ON" is a basic test to determine if there is battery and ignition voltage at the ECM.
^ No DLC data may be the result of an ECM problem, and CHART A-2 will diagnose an ECM problem. Related Tests, Information and Procedures
^ If TP sensor is less than .2 volt. the TP sensor 5 volt reference circuit could be shorted to ground. If TP sensor is over 2.5 volts. the ECM could be in the "Clear Flood Mode" which may cause the engine to not start.
^ The scan tool should display RPM during cranking.
2. Because the Electronic Ignition (EI) system uses two plugs and cables to complete the circuit of each ignition coil, the companion spark plug cable should be grounded.
3. This step determines if injectors or harness are cause of the problem. This test is performed with injectors I & 4 then 2 & 3 in parallel.
4. This test light should flash, indicating that the ECM is controlling the injectors. How bright the light flashes is not important.
5. Ignition may have to be cycled "ON" several times to obtain maximum fuel pressure.
6. Damage to ECM injector driver may occur if any injector is shorted internally. CHART C2-A will diagnose a faulty injector. Chart C-2A Injector Coil Test Procedure
7. This test will determine if the 12 volts supply and a good ground is available at ignition coil assembly.
8. The spark plug cables should be measured with a ohmmeter for correct resistance (each wire should be less than 30,000 ohms).
9. This test will determine if the ECM is not triggering the ignition coils or if the ignition coil is faulty.
10. This test will determine if the ECM is at fault or the harness from ECM to ignition coil assembly is open/shorted.
11. This test checks for ignition voltage at the injector harness connector.
12. Checks for open in CKT 467 or CKT 468 from ECM to fuel injector(s). The test light has a path to voltage through the injector windings to ignition CKT 439.
13. Checks for short to voltage on CKT 467 or CKT 468 from ECM to injectors. Be sure all injectors are disconnected from injector harness connectors.
14. Damage to ECM injector driver may occur if either injector driver CKT 467 or CKT 468 shorts to voltage.

Diagnostic Aids:
^ Water or contamination in fuel system can cause a no start condition during freezing weather. The engine may start after approximately 5 minutes in a heated shop. The problem may not recur until an overnight park in very cold or freezing temperatures.
^ An EGR valve sticking open can cause a lean air/fuel ratio during cranking. Unless the ECM enters "Clear Flood Mode" at the first indication of a flooding condition, it may result in a not start condition.
^ Low fuel pressure can result in a very lean air/fuel ratio. Refer to CHART A-7. Related Tests, Information and Procedures
^ An A/C refrigerant pressure sensor with a internal short to ground can cause a no start condition. Disconnect the A/C refrigerant pressure sensor. If vehicle starts, replace faulty sensor.
^ A MAP sensor stuck between .5 and 2.5 volts can cause a no start condition. Disconnect the MAP sensor. If vehicle starts, replace faulty sensor.