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Cam Position Sensor / Grounding Trouble - PLEASE HELP!

9K views 2 replies 2 participants last post by  n0ekt 
#1 ·
Hello all -

A few questions, if anyone's got the time to help out (truck specs in sig)...

Last year, I had an odd issue with overdrive and the lockup clutch 'fluttering' when it would try to shift to overdrive. I got some help here, and got some new batteries, cleaned all of the connections, and took off the negative battery cable where it attaches to the bottom of the engine block and cleaned it and put it back together. It worked PERFECTLY. (Thanks again BTW!!)

Until this year... same thing happened. I figured it's been a year, maybe corrosion has built up again and all of the connections need to be cleaned.

I waited a little longer than I should have to actually do it, since I knew (thought I knew) what the problem was.

Well, a week into it (just been turning OD off...) The engine throws P0341 (Cam Shaft Position Sensor). Three miles after that, the Tachometer is reading zero. A mile after that, the engine can barely run.

I get home, take off all the battery cables and clean everything just like last time, and it works like a charm. OBDII scan checks out, Tach is back, OD is working, engine is running perfectly. Drive it about 20 miles to test, still perfect.

This morning, on the way to work (10 miles into the trip), the light comes back on, and it's giving a P0341 code again. Tachometer goes to zero, engine sputtering a bit, but still running.

I pull over, clear the code, and the tach comes back and the engine runs fine.

20 miles later it comes back.

This time, it clears, and then comes IMMEDIATELY back.

SO: My questions are these...

1) Am I on the right track with checking the grounds, and are there more that I should check?

2) If it's actually a bad sensor... why would cleaning all the grounds (or clearing the code, for that matter) have brought it back, temporarily? Was it just "on its way out" and working intermittently, and now it's "all the way out"?

3) Can the sensors be damaged by operating for a prolonged period with bad grounding? That is, did waiting to resolve the smaller problem result in a larger one?

4) Does the tachometer actually rely on the signal from the Cam Position Sensor, or are those going to be two separate issues?

5) Does it make sense at this point to buy and install a new Cam Position Sensor, or are there other things that I could/should do to troubleshoot?

Any help greatly appreciated, thanks!!!
 
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#2 ·
The CMP sensors do fail from time to time, in the same fashion that the CKP fails on the older model trucks. CKP being the crank position sensor, which was on 98 and 99 models and 2000's had both CMP and CKP. Anyways when my CKP failed on my truck, I had a similar thing, the truck wouldn't run right, the tach would die etc... I never tried cleaning the grounds, however, If I cleared the codes, it would run fine for a while, sometimes a week, sometimes less than an hour. Also, sometimes the tach would go away for several seconds at a time and the truck would run rough, and sometimes, it would just hiccup. All this equates to is yes they do fail, and they won't necessarily, and in most cases don't, just completely die. But the signal will get weak or intermittent, and the tach is tied to it as well.
Sean
 
#3 ·
Sean -

Thanks for the reply... in the end, you were right, the sensor was going out. The grounds (and cleaning them) had some temporary effect on the code being thrown, but yeah, it needed to be replaced. No trouble since.

Replacing that thing was a riiiiiiiidiculously tight squeeze though. :bang
 
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