Chart A-3 Engine Cranks But Will Not Run

Chart A-3 W/CMFI (PCM):

Chart A-3 W/CMFI Circuit (PCM):

Circuit Description:
This chart assumes that battery condition and engine cranking speed are OK, and there is adequate fuel in the tank.

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

1. A "Service Engine Soon" light "ON" is a basic test to determine if there is a 12 volt supply and ignition 12 volts to control module. No ALDL may be due to an control module problem and CHART A-2 will diagnose the control module. If TPS 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 control module 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 ST-125 (J 26792) or equivalent. No spark indicates a basic ignition problem.

3. Use an injector test light like BT-8320, or equivalent, to test each injector circuit. A blinking light indicates the control module is controlling the injectors.

4. This test will determine if there is fuel pressure at the CMFI unit and holding steady. Use fuel pressure gage J-34730-1. See Chart A-6. Wrap a shop towel around the fuel pressure tap to absorb any small amount of fuel leakage that may occur when installing the gauge.

5. Checking resistance of the injector will determine if the injector is at fault.


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 Testing and Inspection
- Low fuel pressure. Chart A-6 Fuel System Diagnosis
- Water or foreign material in the fuel system
- A grounded CKT 423 (EST) may cause a "No Start" or a "Start then Stall" condition
- Basic engine problem