QuestionHey Roland! Well after getting my hands on the Haynes book, I went through and continued checking things, couldnt find anything, so I ordered a new pcm! Came in today, I will put it in tommorow. I will let you know if that was it. If its not,I will burn the car, LOL! What are some causes that may make the pcm fail? It just had it replaced like 3 yrs ago. (car was my inlaws car) I saw no way to rate you, says you do not accept ratings? Is there anything else I can do? You have been VERY helpful! Thanks!
AnswerHi Ken,
I am unaware of any specific reasons why PCM would fail, other than overheat or over-voltage. Also there are codes that should pop-up were that the case, such as 0600,0601. I wonder if, because it is a '97 which was on the 'trailing edge' of the obd changeover, you can get codes with your ignition key and the check engine light:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light to see if it begins to flash, pause, flash, etc. Let me know if any thing other than 5 and 5 flash sets come out. And you did check the egr valve to be sure it is tight shut, correct? About the only other thing that wouldn't cause a code and still prevent a start would be an obstructed exhaust catalytic converter but that is too costly to replace without verification that it is plugged. You are getting spark, and fuel pump action as I recall. Unless one of the sensors is marginal but not so bad as to set a fault code, I can't think of anything else. I once had the MAP sensor go out of spec but it didn't set a fault code, for example. I was on a trip and fortunately a sharp tech at a Chrysler dealer used his DRB and noticed that the MAP said it was operating on a mountain top while actually we were at sea level. No code, but replacing the MAP was what restored the ability to start and run like it should. Something like that is always possible, but without some evidence I would not be inclined to start buying sensors. The MAP signal at rest near sea level should be around 4.7V. Also check that the coolant temp sensor is around 10,000-14,000 ohms when cold. That too, if off value, would affect mixture.
Thanks for telling me about the no access to Thank/Rate... It should be there now, as I forgot to change the settings on my home page to allow for that. I just started to 'harvest' such opinions for the month of January this afternoon, as you saw, so maybe not too many others were similarly frustrated. It does provide an alternative way to get back to me with a response without having to wait for me to be available to take a question. If you care to, and you can find all the q/a we have exchanged, you are entitled to rate every one of them!
Good luck tomorrow. There has to be an answer to your no start.
Roland
