- Self-Diagnostic System Check

Some failures of the fuel metering system will result in an "Engine Cranks But Won't Run" condition. If this condition exists, refer to Computers and Controls / System Diagnosis / Procedures / Diagnostic Charts / Chart A4-3. Testing and Inspection
This chart will determine if the problem is caused by the ignition system, Electronic Control Module (ECM) or fuel pump circuit.

For fuel system diagnosis, refer to Computers and Controls / System Diagnosis / Procedures / Diagnostic Charts / Chart A4-7.
Testing and Inspection
This includes the injectors, pressure regulator, fuel pump and fuel pump relay. If a problem occurs in the fuel metering system, it usually results in either a rich or lean exhaust condition. This condition is sensed by the oxygen sensor and causes the ECM to change the fuel calculation (injector pulse width). The change made to the fuel calculation will be indicated by a change in the integrator and block learn values, which can be monitored by a "SCAN" tool. A short term change to the fuel calculation is indicated by the integrator value, while a long term change is indicated by the block learn value. Average integrator and block learn values will be around 128, but may vary slightly from engine to engine.

For further fuel system diagnostics and wiring schematic refer to Computers and Controls / System Diagnosis / Procedures / Diagnostic Charts / Code 54. Testing and Inspection