Part 1 of 2

Chart A-3 Part 1 Of 2:

Chart A-3 Wiring Diagram:

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. This chart assumes that battery condition and engine cranking speed are OK, and there is adequate fuel in the tank. If engine starts but immediately stalls, refer to Diagnosis By Symptom Testing and Inspection A "SERVICE ENGINE SOON" (SES) light "ON" is a basic check for ignition and battery supply to the Electronic Control Module (ECM).

2. No spark indicates a basic High Energy Ignition (HEI) problem.

3. This test will determine if the ECM is receiving the reference signal and controlling the injectors. This test could also be performed at the 4-way injector connector by using a test light between terminals "A" and "D." If the test light "blinks" while cranking, then ECM control should be considered OK. How bright the test light "blinks" is not important. However, the test light should be a J-34730-2 or equivalent.

4. Use pressure gauge J-34730-1. Wrap a shop towel around the fuel pressure tap to absorb any small amount of fuel leakage that may occur when installing the gauge.

DIAGNOSTIC AIDS:

An Exhaust Gas Recirculation (EGR) valve sticking open can cause a low air/fuel ratio during cranking. Unless engine enters "Clear Flood" at the first indication of a flooding condition, it can result in a no start. Check for fouled plugs:

If the Throttle Position Sensor (TPS) is sticking or binding in the wide open throttle position, the ECM will be in the "Clear Flood" mode.

Check that injectors on both sides of engine will cause a test light to "blink." Checking of two injectors on each bank in this manner will locate a shorted injector. If above are all OK, refer to Diagnosis By Symptom Testing and Inspection

Also check that the injectors are not open or shorted.