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Can a TPS go bad?

Chad989of2000

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Joined
Jan 13, 2005
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1,791
Location
Livermore, CA
Never heard of it just wondering if that's what's causing my idle insanity. I can tighten and loosen it and it changes how the car idles (surging when all the way down), but if I somehow find a way to get it a good idle, the next time I start the car idle issues begin again. The BISS is almost all the way down. What happens as I currently have it set up is that the car almost stalls with a little throttle but eventually picks up. However, the car will stay at 2000+rpm even when I take my foot off, yet if I press the gas again it will dive down to almost stalling and mini-surging 600-800rpm...it does this when driving too. What is really going on?
 

324vr4

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Apr 28, 2006
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1,240
Location
Bozeman, Montana
the only tps experience i have had is on my jeep. it wouldn't idle at the same rpm continuously and it was so sparadic at all other rpm's. i tried everything i could think of with no results so i took it to a mechanic and it was the tps. he said after about 80-100,000 miles they tend to crap out. i would try a new tps. good luck
 

Barnes

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Feb 9, 2003
Messages
6,249
Location
Richland, WA
Yes, new TPS. Although you can test them to see if they are bad. Not a bad idea since they are kinda expensive.
 

steve

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Sep 11, 2003
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18,897
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NJ
Very expensive new, you can get a used one cheap and test it... its a personal choice I guess. It was very expensive for a new one though.
 

Chad989of2000

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Jan 13, 2005
Messages
1,791
Location
Livermore, CA
How does one go ahead and test a TPS to see if it's functioning correctly? I'm all about the cheapest solution to any problem.
 

Barnes

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Feb 9, 2003
Messages
6,249
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Richland, WA
RTFM! /ubbthreads/images/graemlins/grin.gif

The test isn't too confusing, but you need the procedure out of the manual. I'll try to get it to you this weekend if someone else doesn't come up with it sooner.
 

s_firestone

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Joined
Jun 27, 2002
Messages
1,610
Location
Park City, UT USA
The TPS is a simple potentiometer AKA variable resistor. You find them commonly in old stereos, etc as volume controls. They can and do go bad. Most of the time the contact points on the wiper arm get dirty, stop smoothly transitioning from one resistance to another. In an old stereo you would hear it as static and popping when you turned the knob. Sometimes they can be cleaned (electrical contact cleaner), sometimes they can't. Sometimes they fail open, or at a particular resistance, appearing to be stuck even though they turn freely.

To troubleshoot one simply hook up a multimeter and measure the resistance while rotating the TB shaft. With the throttle plate closed it should measure around 1K ohms. When fully open it should be about 5K ohms. The transition should be smooth. They are easier to read with an analog meter because you can see the needle moving smoothly.

TPS adjustment and test

From the DSM VFAQ site:

DSM VFAQ
 
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