I am a DIY'er and after completing Danner's instructional videos while following along with the book I bought a (mechanics special) project car to reinforce / embed my new knowledge (and to apparently remind me that I'm not as knowledgeable as I thought I was).
The car will only start and run if the humidity is above 90% and then it will try to die but I can keep the RPM's up and keep it running.
All other times (KOEO) it will not start and the lights in the cluster are blinking, gauges are sweeping up and down, odometer blinks "ERROR", relays under the hood are clicking, throttle actuator going crazy and fuel pump relay in the trunk is going nuts. Most of this still goes on even if the engine is running.
The starter will only engage for a split second (random & erratic) using the key, but will crank normally if I use a start button jumped to the starter terminals. Sometimes I have injector pulse and spark, sometimes I don't.
I have checked all powers & grounds with a DVOM, cleaned most all of them anyway and added Stabilant 22 to them just for added protection (including computer connections). All were way under 100mv.
I have scan tool communication, showing a couple ABS codes and one fuel sending unit code. I have disconnected every sensor I can think of, disconnected modules, tried a different battery and tested the data bus with a Uscope (still learning with the scope).
I really think the problem is a PCM, but the intent here is to learn how to be as sure as possible through testing.
Any suggestions would be very much appreciated.
P.S. I bought the car from a friend. It sat in his yard for one month before I got to it. Prior to that it had never left him stranded but had been giving him these driveability problems for months.
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