Chart A-3 Engine Cranks But Will Not Run - PCM

A-3 Chart:

A-3 Circuit:

Circuit Description:
This chart assumes that battery condition and engine cranking speed are OK, and there is adequate fuel in the tank. This chart should be used on engines using the Model 220 throttle body.

Chart Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.

1. A MIL (Service Engine Soon) "ON" is a basic test to determine if there is a 12 volt supply and ignition 12 volts to PCM. No serial data may be due to a PCM problem and CHART A-2 will diagnose the PCM. If TP sensor is over 2.5 volts the engine may be in the clear flood mode which will cause starting problems. If coolant sensor is below -30° C, the PCM will provide fuel for this extremely cold temperature which will severely flood the engine.

2. Voltage at the spark plug is checked using spark tester tool (J 26792). No spark indicates a basic ignition problem.

3. While cranking engine there should be no fuel spray with injectors disconnected. Replace an injector if it sprays fuel or drips like a leaking water faucet.

4. Use an injector test light like BT-8320, to test each injector circuit. A blinking light indicates the PCM is controlling the injectors.

5. This test will determine if there is fuel pressure at the injectors and that the injectors are operating.

Diagnostic Aids: If no trouble is found in the fuel pump circuit or ignition system and the cause of a "Engine Cranks But Will Not Run" has not been found, check for:
^ Fouled spark plugs.

^ EGR valve stuck open.

^ Low fuel pressure. Refer to CHART A-6 Related Tests, Information and Procedures .

^ Water or foreign material in the fuel system.

^ A grounded CKT 423 Ignition Control (IC) may cause a "No Start" or a "Start then Stall" condition.

^ Basic engine problem.

The PCM has integrated IC circuits that are fault protected, therefore, if a circuit has failed, the integrated IC may not be damaged and will keep the circuit open until the fault in the circuit has been corrected. When the fault has been corrected, reinstall PCM and check circuit. Replace PCM only if the circuit is still inoperative.