Robert Howe wrote:
> Found the problem.... probably what happened to those of you that suggested
> the pickup plate.
>
> That's exactly what was wrong. The magnetic sensor on the plate was broken
> off by a pin that had worked it's way loose from the shaft. I'm picking up a
> new plate tomorrow when the parts store opens.
>
> Thanks to those DML'ers that suggested the plate, and if I would have
> checked this earlier, I would be driving my truck right now. :)
>
> To put this into perspective, it seems kinda strange that the distributor
> shaft, tells the ECU when it should fire, then the ecu tells the coil to
> fire, then it goes back through the distributor to go to the individual
> plug. Just something that was beyond my grasp till tonight. Hopefully
> someone will catch this on the archives, and learn from my stress.
Rob,
Glad to hear that you are making some progress. Just to clear up that last
paragraph - the distributor doesn't tell the ECU when to fire. To quote some
diagnostic text:
"Engine Start-Up
This is an open loop mode. When starter is engaged, PCM receives input
from battery voltage, CKP sensor, CMP sensor,
ECT sensor, IAT sensor, MAP sensor and TP sensor. Based on these inputs,
voltage is applied to fuel injectors with PCM
controlling injection sequence, rate, and pulse width. PCM provides ground for
injectors to fire in proper order.
PCM determines proper ignition timing according to input received from CKP
sensor. If PCM does not receive CKP sensor
signal within 3 seconds after engine begins cranking, fuel injection system is
shut down and a Diagnostic Trouble Code
(DTC) is set in PCM memory."
If you read carefully - you'll see that only the CKP (crankshaft) sensor is used
for ignition. The only reason that the CMP (camshaft sensor - located in
distributor) sensor is even read at this point is basically to set the proper
injector firing sequence. Hence the name "SEQUENTIAL Multi-Port (fuel)
Injection". Since the PCM is controlling both fuel and spark - the CMP sensor
as well as the CKP sensor has to be read in order to start the vehicle.
Latr,
Shane
-- '96 IndyRam w/lots of mods (mine) '96 IndyRam w/lots of options (wifes) - also a numbered (#142) "Track Truck" '74 Triple-Black Dodge Challenger Rallye 360 home-brew EFI R&D vehicle '68 Black Corvette Convertible 427 (For Sale)
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