2002 Pontiac Grand Prix loss of power

Tiny
DRAZIW_ONE
  • MEMBER
  • 2002 PONTIAC GRAND PRIX
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 210,567 MILES
Have a 3800, suspect converter is problem. Have all ready changed fuel filter, checked air filter, bit dirty but not enough to cause the problem. Had worse and not give same power loss. Backed exhaust off at manifold and tried to rev motor, wouldn't go past 4000. Now past experience when I had plugged converters I was able to still rev the motor past 4000 and not have it seemly misfire. So put exhaust back together but now I read that this car has/might have a rev limiter?
Monday, June 15th, 2009 AT 1:22 AM

5 Replies

Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
If you disconnected exhaust before convertor and it would not rev past 4000, then it is not a convertor problem. While it may have a rev limiter, it is certainly not set for 4000.

Check fuel pressure with mechanical gauge and spark with spark tester.
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Monday, June 15th, 2009 AT 6:52 AM
Tiny
DRAZIW_ONE
  • MEMBER
  • 3 POSTS
Update to my previous question about loss of power. It was in fact the converter being plugged at least 75%. What I did, I used a chop saw to cut the pipe on the front of the converter to look at the inlet side with the idea if it wasn't plugged then I would just weld it back up. I thought about punching it out but went to my local automotive store and found a universal converter for $75 Can plus taxes and welded that into place. Took it for a test drive and the cars working like new again A little noisy as I used the old gaskets because the store didn't have any in stock which I will replace here in a day or so.
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Tuesday, June 16th, 2009 AT 1:28 AM
Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
Good news, but you need to find out why the convertor was plugged. They will get plugged because of incorrect A/F ratio or an impact event.
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Tuesday, June 16th, 2009 AT 7:35 AM
Tiny
DRAZIW_ONE
  • MEMBER
  • 3 POSTS
Actually according to the GM dealership, they do have a rev limiter for the sole purpose of missed shifts, or accidental shifting in to neutral. And trying to blow up their engine while in park.

Granted, that it will be needed to be checked out for the cause of it getting plugged. The car has 210K and I suspect that the price of gas being 99.9/liter had the previous owner buying the lowest grade. Also with that high of kilos I have a suspicion that the O2's have become lazy. There isn't/wasn't any lights on indicating error codes in the computer. I don't have axcess to a scanner at the moment so I can't tell for sure.


https://www.2carpros.com/forum/automotive_pictures/369201_IMG_0023_2.jpg


https://www.2carpros.com/forum/automotive_pictures/369201_IMG_0024_2.jpg

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Tuesday, June 16th, 2009 AT 11:01 AM
Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
They may have a rev limiter, but it would be set to 500-600 under max rpm.

The convertor looks like the engine is running rich or has multiple misfires.
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Wednesday, June 17th, 2009 AT 6:53 AM

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