Circuit Description

During cranking, the ignition module monitors the dual crank sensor sync signal. The sync signal is used to determine the correct cylinder pair to spark first.

After the sync signal has been processed by the ignition module, it sends a fuel control reference pulse to the ECM. When the ECM receives this pulse it will command all six injectors to open for one priming shot of fuel in all cylinders.

After the priming, the injectors are left off for the next six fuel control reference pulses from the ignition module (two crankshaft revolutions). This allows each cylinder a chance to use the fuel from the priming shot.

During this waiting period, a cam pulse will have been received by the ECM. Now the ECM begins to operate the injectors sequentially based on true camshaft position.

However, if the cam signal is not present at start-up, a Code E041 will set and the ECM will start sequential fuel delivery in random pattern with a 1 in 6 chance that fuel delivery is correct.