1991 Chevy Cheyenne doing work on the truck w/battery conne

Tiny
E DUB
  • MEMBER
  • 1991 CHEVROLET CHEYENNE
  • V8
  • 2WD
  • AUTOMATIC
  • 142,000 MILES
HEY,
had all the sparkplugs an wires, a few sensors removed, inspected an replaced along with the cap an rotor, even pulled the dist. Out replaced and put back together, then realized the battery was never disconnected. Now the PCM/ECM is fried. Is this related?
thanks
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Sunday, February 14th, 2010 AT 12:46 AM

7 Replies

Tiny
JACK42
  • MEMBER
Not likely. Just plugging and unplugging sensors will do that. The PCM's in newer cars are much more durable than ones from years ago. They can take quite abit before they "fry".
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Sunday, February 14th, 2010 AT 8:27 AM
Tiny
E DUB
  • MEMBER
I'm in need of a little more specifics
you stated that " Not likely. Just plugging and unplugging sensors will do that"
so does that mean by having the sensors removed without the battery being disconnected, this could lead to, cause the fried PCM/ECM. Here's the list of sensors removed/work performed with the battery connected. TPS Throttle Position Sensor removed, also removed the (IAC) idle control valve along with the throttle body unit being removed and cleaned. Along with the (MAP)sensor and the (MAF). ALL these where removed, new parts installed in an attempt to remedy the situation, the situation being the truck was running like crap, lack of power, hesitation, popping, long story short. The mechanic at a last ditch attempt to find the problem did a compression test, the results where 65psi in 4 cylinders, the rest of the cylinders where at 90psi. So the problem was found. No compression, the motor was rebuilt, reinstalled. The day came to pick up the truck, went down to the shop and mechanic stated he placed the wrong piston rings in the truck an that it would have to be rebuilt again! So now where on the second rebuild, the 2nd motor reinstalled but now the Mechanic says the PCM/ECM is fried. So my question is could this be the fault of the mechanic an error on his part? Or should I have to foot the bill for the new PCM/ECM.I'm down here in southern Mexico, Oaxaca. And ther's no auto zone or napa auto parts here, so I've gotta ship parts to the u.S. The question being did the mechanic working on my truck inadvertently fry the PCM/ECM. Is it standard to replace when replacing the motor?
Thanks again
eric
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Sunday, February 14th, 2010 AT 12:31 PM
Tiny
JACK42
  • MEMBER
Sounds more like they may have grounded out the electrical when working on the engine, just the sensors wont fry the PCM. This one is on them in my opinion
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Sunday, February 14th, 2010 AT 4:50 PM
Tiny
E DUB
  • MEMBER
Well that makes sense.
Is there any way to confirm this? Other than my fried cpu? How would
one ground out the electrical, more importantly how can I prove this
was his error? Any tips, suggestions or advice will be mulled over with
great contemplation. Thanks again
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Sunday, February 14th, 2010 AT 7:46 PM
Tiny
JACK42
  • MEMBER
The fact that it ran before, and only had mechanical issues (low compression on 1/2 the engine). Then mysteriously when they put t all back together it
needs a PCM? If giniton was left on and system power leads were grounded out, it could feesibly hurt the PCM, I personally havent fried one in 20
years so Im not sure exactly what it would take.
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Monday, February 15th, 2010 AT 7:14 AM
Tiny
E DUB
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Thank you for your insight on these questions!
You knowledge on this situation has given me the confidence to address this in a more appropriate manner. Thanks again
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Monday, February 15th, 2010 AT 8:28 AM
Tiny
2CARPROS LINSEY
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Thank you for your donation, we hope we help you in the future.
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Monday, March 1st, 2010 AT 2:23 PM

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