Check Fuel Pulse Width (FUEL PW) While Cranking

Purpose:
To verify that the Fuel Delivery Command Signal (FDCS) system is functioning correctly.

Recommended Procedure:
Connect OBDII Scan Tool to the data link connector (DLC) under the dash. Access FUEL PW PID on NGS Tester and monitor while cranking engine.

No fuel command signal when ICP, RPM and VPWR signals are correct usually indicates a loss of CMP sync signal. 

A 1 to 6 ms fuel pulse width will be sent by the PCM to the IDM when a sync pulse has been received from the CMP sensor and when sufficient injection control pressure is present. A 0.42 ms fuel pulse width (a no fueling pulse) will be sent by the PCM when a sync pulse has been received from the CMP sensor and if insufficient injection control pressure is present. This 0.42 ms fuel pulse width will not allow injectors to be enabled, but does keep the IDM and PCM synchronized until sufficient injection control pressure is realized.

Possible Causes:

• FDCS circuitry.
• PCM.
• IDM.

Tools Required:
Rotunda New Generation Star (NGS) Tester 007-00500 or equivalent scan tool.