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what happens with disconnected TPS

Old 01-26-2007, 10:40 AM
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Question what happens with disconnected TPS

Simple question, What happens if the TPS is not hooked up? How will the engine run? More specifically, engine started running like crap, felt like it was missing and had very little power. And it will die at idle. Even going 65 with and warmed up, if I put in neutral and let off the gas it dies. Help, thanks.
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Old 01-26-2007, 10:42 AM
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Have you checked for any vacuum leaks?
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Old 01-26-2007, 10:48 AM
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Almost 100% no vacume leak, but it definetly feels like one.
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Old 01-26-2007, 10:50 AM
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Standard quick stuff probably is a good idea- spark plugs, wires, air filter, check fluids, etc...
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Old 01-26-2007, 11:19 AM
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car should start and idle w/ the TPS disconnected, but it'll die as soon as you touch the throttle.
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Old 01-26-2007, 11:59 AM
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Originally Posted by jht3 View Post
car should start and idle w/ the TPS disconnected, but it'll die as soon as you touch the throttle.
I disconnected mine once to test someone's theory about why a SplitSecond black box wasn't working.

So, with the understanding that I'm in a 3rd gen with a 3.4L, mine idled and ran "okay' up to about 2000RPM. Under load it had no power, and no throttle response above that 2k mark.

Last edited by midiwall; 01-26-2007 at 12:19 PM.
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Old 01-26-2007, 12:13 PM
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if your tps was disconnected you would get a CEL. Have you checked for CEL codes lately? Have you checked the air tube between the AFM and the throttle body for leaks?
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Old 01-26-2007, 12:50 PM
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I havent checked for codes because the light doesent come on. Should I try to pull them anyway? Im looking really hard to try to find some air leak because that is what it feels like.

You mentioned fluids, would a low fluid level cause this kind of problem (stumbling during acceleration, loss of power).
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Old 01-26-2007, 02:09 PM
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Does your CEL work? when u start your car up it should come on for a few seconds just to show u that the bulb isnt burnt out.
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Old 01-26-2007, 02:15 PM
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If that is the only test to see if it works, then yeah the light does come on for a few seconds. Any thoughts would be great cause iv been at it for days.
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Old 01-26-2007, 02:40 PM
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transmission will not shift properly either
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Old 01-26-2007, 02:54 PM
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Manual transmission shifts just fine. Starts up everytime, even when it 30 degree outside. burning fuel a little quicker.
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Old 01-26-2007, 03:08 PM
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Originally Posted by Lifelongtoy View Post
Simple question, What happens if the TPS is not hooked up? How will the engine run? More specifically, engine started running like crap, felt like it was missing and had very little power. And it will die at idle. Even going 65 with and warmed up, if I put in neutral and let off the gas it dies. Help, thanks.
On my 2nd generation, disconnecting the TPS threw a code, but the truck ran perfectly.

If the TPS is not adjusted correctly as evidenced by a 500rpm idle, and hesitation with initial acceleration, unplugging the TPS connector should then cause a correct idle, and a normal acceleration.

Correcting the TPS then produced a correct idle, and no code.

Granted that is based on my experience, and the experience of several others with whom I've had exchanges.

Apparently others have had different experiences.

Be nice to have more data.
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Old 01-27-2007, 10:20 PM
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Originally Posted by rdharper View Post
On my 2nd generation, disconnecting the TPS threw a code, but the truck ran perfectly.


Apparently others have had different experiences.

Be nice to have more data.
I disconnected mine for a day once in a misguided troubleshooting attempt. It ran as well without it, but caveat here is that I already had a CEL for the knock sensor. Anyways - my 1990 3vze ran OK without the tps connected - however I suspect that it was already running in "failsafe mode"
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Old 01-28-2007, 02:43 AM
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Originally Posted by BC Rider View Post
I disconnected mine for a day once in a misguided troubleshooting attempt. It ran as well without it, but caveat here is that I already had a CEL for the knock sensor. Anyways - my 1990 3vze ran OK without the tps connected - however I suspect that it was already running in "failsafe mode"
Interesting. For the record, I had no codes prior to the disconnect. My symptoms prior to fixing the TPS were low RPM, and hesitation on initial acceleration.

I would think "fail safe" mode would be pretty miserable performance, although I couldn't find enough information on it to know one way or another. Neither for 2nd generation, or in general.
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Old 01-28-2007, 09:45 AM
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Originally Posted by rdharper View Post
I would think "fail safe" mode would be pretty miserable performance, although I couldn't find enough information on it to know one way or another. Neither for 2nd generation, or in general.
You're right - my truck was already running poorly - but ran no worse after the tps disconnect. I already had a code 52 which apparently retards the timing to a safe value to prevent pinging. I've probably used the term "failsafe" incorrectly here - should of been more specific.
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Old 01-28-2007, 11:17 AM
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Originally Posted by BC Rider View Post
You're right - my truck was already running poorly - but ran no worse after the tps disconnect. I already had a code 52 which apparently retards the timing to a safe value to prevent pinging. I've probably used the term "failsafe" incorrectly here - should of been more specific.
Ok, that makes sense. That fits with what I believe is accurate.. ie: if you disconnect the TPS and performance improves, then the TPS is not working correctly. Failure of the throttle to fully return to its physical stops, or misadjustment (I believe) is the most common fault, failure of the TPS or wiring, second most likely.
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Old 05-15-2019, 07:13 PM
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Tps

ok my toy started dieing randumly but start right back up, replaced mass air sensor and tps the tps made it high low ideal and bogg. Unpluged it runs good has good power is it fine to run with it unplugged
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