Chart A-3 Engine Cranks But Will Not Run

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

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

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

Ignition System And Injectors:

CIRCUIT DESCRIPTION
The ignition system uses a waste spark method of spark distribution. In this type of ignition system, the ignition control module triggers the correct coil pair based on both signals from the crankshaft sensor, resulting in both spark plugs firing at the same time. One cylinder is on the compression cycle while the other one is on the exhaust cycle, resulting in a lower energy requirement to fire the spark plug on the exhaust cycle. The remaining high voltage is used to fire the spark plug on the compression cycle.

During cranking, the ignition control module monitors the crankshaft position sensor sync signal. The sync signal is used to determine the correct cylinder pair to spark first. After the sync signal has been processed by the ignition control module, it sends a fuel control reference pulse to the PCM. When the PCM receives this pulse it will command all six injectors to open for one priming shot of fuel in all cylinders. After the priming, the injectors are left "OFF" for the next six fuel control reference pulses from the ignition control module (two crankshaft revolutions). This allows each cylinder a chance to use the fuel from the priming shot. During this waiting period, a cam pulse will have been received by the PCM. Now the PCM begins to operate the injectors sequentially based on true camshaft position. However, if the cam signal is not present at start-up, DTC P0342 will set and the PCM will start sequential fuel delivery in random pattern with a 1 in 6 chance that fuel delivery is correct.

NOTE: The sync signal is used only by the ignition control module. It is used for spark synchronization at start up only (not passed to the PCM).

TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. A blinking injector test light verifies that the PCM is monitoring the fuel control signal and attempting to activate the injectors.
2. The crankshaft position sensor has been verified as functioning properly, as is evidenced by the blinking injector test light. A fuel pressure test, at this point, will separate the diagnostic path into either a fuel related fault or ignition system malfunction.
3. By testing for spark on plug leads 1, 3 and 5, each ignition coil's ability to produce at least 25,000 volts is verified.
4. By testing the problem coil's control circuit with a test light, a determination can be made as to the problem coil being faulty or the ignition control module's internal driver for that coil being the source of the complaint.
5 Tests for battery voltage on CKT 1039. If voltage was present, the "light OFF" test result was caused by no activation pulse reaching the injector connector from the PCM
6. The test light to 12 volts simulates a reference signal to the PCM, which will result in an injector test light blink with each touch of the test light to terminal "D". It may take up to three touches to get an injector test light flash. If light blinks, CKT 430, the PCM, and the injector driver circuits are all OK. Ensure that all injectors are disconnected prior to this step to avoid possible flooding.
7. Checks CKTs 644, 645, 646 and 3X portion of the crankshaft position sensor. If CKT 646 has been shorted to voltage, make sure crankshaft position sensor has not been damaged.
8. Checks CKT 573 and the 18X portion of the crankshaft position sensor. If CKT 573 has been shorted to voltage, make sure crankshaft position sensor has not been damaged.
9 Verifies ignition feed to the ignition control module