Input Signals Required to Pulse Injectors

There are three signals which are necessary to operate the fuel injectors. These are the Ne, G, and IGf signals. Inside the ECU, the Ne Signal is used to produce an injection chive signal. The G signal is used to determine the timing of the injection signals. The IGf signal is monitored for fuel delivery fail-safe. (With Conventional EFI, the IG signal is used to produce the injection drive signal.)

The ECU cannot pulse the injector without an Ne signal and will not start or run if this signal is not present. If the G signal is not present while cranking the engine, the ECU will not be able to identify when to produce the injection signal. The result will be the same, no injection pulse. If the IGf signal is not present, the ECU will go into fuel fail-safe by stopping injection pulses.

If, however, the ECU loses the G signal with the engine running, the engine will continue to run because the timing of injection signals is locked in once the engine starts.

Signal

Engine Condition When Signal Lost

Effect on Injection and Spark

Ne

Cranking

No spark, no injection pulse, engine will not start

Ne

Running

Engine stalls, no spark, and no injection pulse

Gi*

Cranking

Engine will not start, no injection pulse, no spark

Gi*

Running

Engine will continue to run, signal only necessary for starting

IGf

Running or Cranking

Engine will not start or run, no injection pulse

* Applications with G2 will default to either G sensor if the other sensor fails.

* Applications with G2 will default to either G sensor if the other sensor fails.

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