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Tps Stem stuck

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Old 10-03-2007, 06:26 AM
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Tps Stem stuck

Hi,The stem on my tps is fully in and i cant release it.Does'nt seem to be siezed
as i can push it in slightly.Does anyone know if these can be released.

Thanks,
Alicat.
Old 10-03-2007, 06:40 AM
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naf
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Re: Tps Stem stuck

E4MC? Have to remove the airhorn on the carb. TPS is probably bad or the spring under it is fubar.
Old 10-04-2007, 03:39 AM
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Re: Tps Stem stuck

I had the airhorn off,thats when i noticed it was right in.As i said it doesnt seem to be seized or bent,it just wont come up.Seems like it got a WOT signal and stayed there.

Alicat.
Old 10-04-2007, 10:12 AM
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Re: Tps Stem stuck

A new one is inexpensive. Any auto parts store, AZ, etc. will have one.
Old 10-05-2007, 02:22 AM
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Re: Tps Stem stuck

Originally Posted by naf
A new one is inexpensive. Any auto parts store, AZ, etc. will have one.
The only problem there is i am in australia,and when you say it's a rochester they look at you like your an alien.I'll get one from the US over the net if i cant fix it.
Old 10-05-2007, 06:42 AM
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Re: Tps Stem stuck

It's a sealed plastic unit and is probably gummed up with varnish on the inside. Soak it in solvent to try to free it up, but make sure it still functions correctly before trying to re-use it.

I've also found that a stronger spring is sometimes needed beneath these pieces once they get some years on them. Again I suspect varnish accumulating inside the unit begins to interfere with the free movement of the TPS stem. Probably your case at the extreme.
Old 10-05-2007, 07:31 AM
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Re: Tps Stem stuck

I thought of trying that,but i read somewhere that the tps is one of the things that should'nt go in solvent,or can it?.Also can it be tested off the carby and if so how?.Thanks for your help.
Old 10-05-2007, 09:51 AM
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Re: Tps Stem stuck

Originally Posted by alicat
I thought of trying that,but i read somewhere that the tps is one of the things that should'nt go in solvent,or can it?.Also can it be tested off the carby and if so how?.Thanks for your help.
That's why I would recommend checking it after trying to clean it with solvent. The sensor is really just a potentiometer that varies output voltage with plunger position. A quick, off the carb, check could be done by measuring resistance and ensuring it varies linearly with plunger position. This test is by no means proof positive that it will work correctly once re-installed, but could indicate a bad TPS (failing this test = bad; passing this test = maybe good).

I'd really recommend a replacement if at all possible.
Old 10-05-2007, 11:30 AM
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Re: Tps Stem stuck

The real GM replacement TPS sensors are not cheap- about $60 at my local dealership. But their plunger action is very silky and smooth.

I can pick up an auto-parts cheapie for $20. But the action is noticably scratchier and clunkier than a real GM unit.

I've used both with success. But when it's something that really matters to me I usually cough up the big bucks for the genuine GM piece.

Both come with a new spring for under the TPS.
Old 10-05-2007, 11:39 AM
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Re: Tps Stem stuck

i agree, GM prices are bad but they always work great!

I thought Australia had lots of GM stuff. don't they make parts there? maybe that's only the new stuff.
sorry off topic.

With my old camaro i just got sick of it and converted to the old system. Got a different carb, dizzy with vac adv. and you should get an aftermarket torque converter lock up too if you choose this. then again you could get lucky and find the spring?
Old 10-05-2007, 11:45 AM
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Re: Tps Stem stuck

Originally Posted by Damon
The real GM replacement TPS sensors are not cheap- about $60 at my local dealership. But their plunger action is very silky and smooth.

I can pick up an auto-parts cheapie for $20. But the action is noticably scratchier and clunkier than a real GM unit.

I've used both with success. But when it's something that really matters to me I usually cough up the big bucks for the genuine GM piece.

Both come with a new spring for under the TPS.
Good point on the OEM vs. parts store. I always have to weigh the down side (result of failure) with the extra cost for the (usually) more durable, better quality replacement part. In the case of the TPS though, for me, replacement of a failed unit takes about 20 minutes, failure will not leave me stranded and when/if it fails the failure will be nearly immediately evident in reduced performance/mileage. If, however, I were to replace one in a friend's vehicle I would probably recommend OEM, especially if that friend didn't necessarily enjoy spending as much time under the hood as I do. Oh, on the other hand I'll always go with a GM replacement ignition control module.
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