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Camshaft and Crankshaft Sensors--I'M BACK

My saga is found here:

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Here is what has happened since the crankshaft sensor, camshaft sensor, and power control module was replaced.

Vehicle ran good for a couple of weeks, then would occasionally die at idle while at stop lights. This would happen perhaps 1 out of 3 days the car was driven. At highway speeds it would violently jerk--once-- while temporarily lighting the Service Engine light. The jerking was more consistent.

I took it back to the dealer that installed the power control module. There were no stored codes. They suggested that I replace the spark plugs and plug wires and clean the throttle body and fuel system with chemicals. They had pulled a spark plug and its gap was at .090, should be .050. They said once the plugs and wires had been replaced and fuel system cleaned it should take care of it, but if it still exhibited the symptoms I should take it back to them.

I cleaned the throttle body area with 3M Throttle Plate and Intake Cleaner. Didn't do a super thorough job since I Ieft the part intact and sprayed and wiped with a rag inside the throttle body cavity. However, this seems to have stopped the problem with the vehicle dying at idle at stop lights.

Now all that remains is the violent jerk and temporary lighting of the Service Engine light. Curiously, this symptom always occurs at the same area of my wife's drive to work. In fact, she says it is predictable and anticipates when it will happen. She's rarely disappointed.

I don't think it is elapsed time the engine has been running, nor is it distance traveled. I'm thinking it's related to engine temperature. But what? I doubt this is spark plugs causing this problem. One jerk at about the same time after engine startup and momentary flash of Service Engine Light. Again, when the dealer hooked up the scan tool there were no stored codes.

So, any ideas? Temperature related problem? Some sensor hiccuping?

Reply to
powrwrap
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Not sure if it was on '97 models, but there was a TSB that dealt with a problem like this. It involved removing the knock sensor because it would cause the PCM to reset while driving.

Reply to
bllsht

Hey thanks! I'll research it...

Reply to
powrwrap

Can someone that has access to Chrysler technical service bulletins please post #19-34-98? I believe it is dated 11/27/1998. I found this while searching Yahoo Groups. It may contain the solution to a long running problem. Thanks.

Reply to
powrwrap

not a good number

Reply to
maxpower

18-34-98 is a TSB that requires disconnecting and taping the wire of the knock sensor for a symptom you are describing BUT this only occurs if the Module is resetting itself back to zero and all the learn values resets. A scan tool is required to determine if this is what is happening.

Glenn

Reply to
maxpower

18-34-98 is a TSB that requires disconnecting and taping the wire of the knock sensor for a symptom you are describing BUT this only occurs if the Module is resetting itself back to zero and all the learn values resets. A scan tool is required to determine if this is what is happening.

Glenn

Reply to
maxpower

It doesn't take a scan tool to determine if disconnecting the knock sensor eliminates the symptoms.

Reply to
bllsht

No it doesn't. But the OP stated that it happens sometimes, a scanner would have determined that the PCM went into a reset mode and cleared all learned values

Glenn

Reply to
maxpower

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Reply to
philthy

Considering the MIL gives a flash and there are no stored codes, I'd bet the PCM is resetting. Another trip to the dealer that didn't even bother checking for TSBs, even after repeat visits, is not what I'd recommend.

I'd disconnect the knock sensor and drive it. If the symptoms stop, then it was resetting because of the knock sensor. If the symptoms remain, a scan tool (in the right hands) would be in order.

Reply to
bllsht

cks/breakage and jambed into place i have one if you are near brighton mich= igan

I might try that, but how would a cracked flex plate cause the symptoms to occur at almost the exact same time every time the car is driven?

Reply to
powrwrap

Hmmm...so the scan tool can determine if the PCM is resetting back to zero and erasing any stored codes? If so, shouldn't the dealer have told me that the reason the PCM doesn't have any stored codes is because it's been resetting itself?

Reply to
powrwrap

Well, you just answered my first question that I posted about 30 seconds ago. A scanner can tell if the PCM went into reset mode.

Now I wonder if the dealership knows this and sold me a PCM that I really didn't need.

Reply to
powrwrap

Sounds like a reasonable suggestion. Can anyone give any reasons why I shouldn't disconnect the knock sensor?

Reply to
powrwrap

A good scanner can give the user the info. It's up to the user to interpret that info.

If I remember correctly, you were still getting cam or crank sensor faults before the PCM was replaced. You haven't mentioned any since it was replaced. Could be you've had 2 different problems.

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Reply to
bllsht

Yes, using the Co-Pilot device the stored codes were simultaneous cam sensor AND crank sensors faults. Since I had already replaced them they suspected the wiring between these sensors to the PCM or the PCM itself. The wiring checked out OK, so that left the PCM as the most likely source of the trouble.

I suppose it could be that I've developed another problem since the PCM was replaced that is causing the PCM to reset itself. When the dealership said there were no stored codes, I wonder if they checked to see if the PCM was resetting and clearing them out. I guess I'll call them tomorrow and ask about that and also the TSB.

Reply to
powrwrap

Hmmm...so the scan tool can determine if the PCM is resetting back to zero and erasing any stored codes? If so, shouldn't the dealer have told me that the reason the PCM doesn't have any stored codes is because it's been resetting itself?

Like it was already posted, a tool is only as good as the person using it, but yes it can see that everything has been reset. disconnecting the knock sensor if so equipped wont hurt, but not your problem. The TSB you are referring to is a one time occurrence while driving, it WILL NOT cause severe bucking or constantly surge. What you would experience if this was the problem with a knock sensor would be a quick surge as the PCM reset itself. and then run fine until a next start up.

Glenn

Reply to
maxpower

This is exactly what happens. One sudden jerk, flash of the Service Engine Light, then everything back to normal driving. Next day, same thing, at about the same distance/time traveled.

Reply to
powrwrap

You could have disconnected the knock sensor in the same amount of time it took to post.

Reply to
aarcuda69062

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