QuestionQUESTION: Had too many follow ups, had to start a new question. I made sure i was doing the key on/off correctly, still nothing. I checked for voltage at the red/wht wire, its has voltage all the time and the solid blue wire does have voltage when the key is on the run position. Is it possible it's still the controller? And is there a way to check voltage to/from the camshaft sensor?
ANSWER: Hi Russell,
I realized the on-off-on-off-on was actually 5 steps, not 7, so I am glad you wrote back. In any case, yes, you can check the crank and the cam sensor both: the common ground wire it black/light blue and the signal should be on the gray/black (crank) and the tan/yellow (cam). So put your voltemeter across the signal and ground wires, put ignition in the run position, and then with a socket and breaker bar turn the crank pulley bolt by hand. You should see the voltage change back and forth between 5 and 0.3V several times per engine rotation. If you don't get that pulsing, then the sensor is either bad or it is not close enough to the surface (paper spacer is the distance, it self-deatructs but leaves the sensor close enough without actually touching.
The third wire is orange at each sensor and it should have a constant 9v on them.
Roland
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QUESTION: It's raining here but I ran out and tried something really quick. I tested the black/blue and tan/yellow wires on the camshaft sensor, but I didn't have time to turn it over by hand, I had my wife try to crank it. I get nothing with the ignition on, I get roughly 3.68volts when she tries to crank it, no pulsing. Am I able to check it this way? And if I need to replace it, how the heck do you get to it? hehe
ANSWER: Hi Russell,
No, you were probably reading the average of a pulsing voltage, so probably if you do it by hand you would find that it was as I described. You can't see it with a voltmeter when the engine is turning over that fast. So you might just want to verify by hand. If you get the fuel pump running for a moment when you first turn it to the run position, that would show that the autoshutdown relay is working, at least for a moment. If you get the pulsing from the sensors, then you should get the asd relay to stay on while you crank it. Maybe the asd relay is weak? Try jumping the red/white to the dark green/orange wire at the ASD socket (the asd relay is the fourth one from the front).. That should power the fuel pump and the spark coil(but don't leave it that way it will run down the battery over time). Then try starting it. That would test whether it could be the relay. If you have the sensor pulsing, and the relay jumpered and still no spark, then the coil pack may be no good. But I still don't like the no codes (controller?). Next, see if you are getting any resistance pulsing on any of three wires at the coil plug (the fourth will have 12V on it if you have the asd jumpered). The resistance pulsing (measure resistance between each wire and ground, again while turning the crank by hand, you should get a pulse once per revolution if the controller is taking the sensor pulses and distributing them to the spark coil primaries as it should do.
Roland
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QUESTION: Hello Roland,
I had a local automotive technician come back and hook a scanner up my 92 dodge caravan. He was not able to get any codes either. He said the scanner said to check the camshaft sensor, crankshaft sensor, and if those are ok then its the PCM. As I've already changed the crankshaft sensor and tested the camshaft sensor, so the PCM is likely the culprit. He told me to check fuses and grounds to the PCM, ASD relay, etc. Where, if any, are the fuses or fuseable links for the PCM and ASD relay? Anything else I should check before getting a new PCM?
Thanks again,
Russell
AnswerHi Russell,
The power to the PCM I believe I told you about already and you verified that (pins 3 all the time and 9 switched). The ASD has battery input on the red/white and ignition switched power on the dark blue, and those you verified also. Did you try directly coupling the red/white to the dark green/orange wire at the ASD socket (essentially by-passing the ASD)? And did you verify 0.3 and 5v oscillation by hand at the two sensors? Similarly, how about pulsing on the three wires of the coil pack (the fourth has 12V if you have the ASD by-passed),
Roland
