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Does anyone know the sequence and timing of the ECM’s use of the cam and crank shaft sensors during start? I am troubleshooting a no-start.
The description in the “Engine Startup Mode” section on page 14-90 of the 1994 service manual repeats itself without clearly explaining the sequence of using the cam/crank shaft sensor information. It says both energizing and de-energizing the ASD and fuel pump depend on “receives the sensor signals”, the de-energize action occurring if they are not received within one second of something it does not identify.
(The ASD relay provides common power to the injectors and ignition, from the ignition switch, the ECM switches ground to each injector.
The manual says “The PCM energizes all six injectors until it determines crankshaft position...”, which it does within one second.)
So, my question:
Does it open all injectors on receiving some signal (pulses), then start sequencing injectors on having enough information to be sure of piston position and cylinder ID? (But stopping fuel delivery if not getting enough information.)
The description in the “Engine Startup Mode” section on page 14-90 of the 1994 service manual repeats itself without clearly explaining the sequence of using the cam/crank shaft sensor information. It says both energizing and de-energizing the ASD and fuel pump depend on “receives the sensor signals”, the de-energize action occurring if they are not received within one second of something it does not identify.
(The ASD relay provides common power to the injectors and ignition, from the ignition switch, the ECM switches ground to each injector.
The manual says “The PCM energizes all six injectors until it determines crankshaft position...”, which it does within one second.)
So, my question:
Does it open all injectors on receiving some signal (pulses), then start sequencing injectors on having enough information to be sure of piston position and cylinder ID? (But stopping fuel delivery if not getting enough information.)