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Car idle to WOT by itself


nurkvinny

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Here's a fun one.

 

Let's say you're idling down your driveway one sunny day in a higher horsepower car. While still at an idle, the car decides that it would rather be turning 5500+ rpms and do a burnout in your gravel. :)

 

This wasn't a case of being at a high rpm and the car sticking there, like a stuck throttle cable. The car went to WOT by itself.

 

The question is, what in God's name can I check for this one? I have never seen or heard of this.

 

And yes, I was fucking scared.

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I'm with Doc. Grab your user manual, or go to the back of the car annd look for this..

http://ecomodder.com/blog/wp-content/uploads/2009/01/20070514-toyota-logo.jpg

 

J/K did it only happen once? I heard of a few issues with tunes where the idle would be wierd while in reverse. But I dont think that would be enough to cause a 5500 rpm surge. Cable, pedal, spring, stuck plate????

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J/K did it only happen once? I heard of a few issues with tunes where the idle would be wierd while in reverse. But I dont think that would be enough to cause a 5500 rpm surge. Cable, pedal, spring, stuck plate????

 

Happened once the VERY first time I was ever behind the wheel idling in reverse down my drive. I figured I just hit a patch of ice with the bald drag radials and the brakes didn't hold the car, or I hit the gas with my boots (pedals are VERY close together).

 

That was putting the car into the garage to make some non-related repairs.

 

Today's incident was the second time ever behind the wheel, this one in a forward gear. So, that's two times in a row, batting 100%.

 

Of note - both times the car was in a gear. It seems to idle for a few minutes without revving through the roof when in Park.

 

Some details: Older Ford 302, non-stock throttle body, non-stock everything really.

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It wasn't funny til' afterwards, right? ;)

 

I know you're just joshing, but it still isn't funny to me. Still freaked out about it, really.

 

Besides almost crashing the car, I about took out my detached garage, Ram, and S10. I think if I had been on pavement and not gravel, there would have been no time to think and shut her off. Spinning in gravel was the only savior.

 

Replace it?KillJoy

 

Probably, I've only known this bit of info for 30 minutes. :)

 

And BTW, a red Power Wheels would have been in the path of destruction as well.

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Something has to be creating a vacuum leak, faulty EGR system?, faulty TB?, something like that.

 

Yeah, been out there tonight tracing vacuum lines.

 

Be curious to see on a scan tool, maybe that that buggered up TPS isn't moving with the throttle blade like its supposed to.

 

EGR deleted.

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Yeah, been out there tonight tracing vacuum lines.

 

 

 

EGR deleted.

 

Well I doubt an EGR would cause those symtoms. Is it an auto? Vacuum modulated? Maybe that has something to do with it happening in gear. I really don't know, but maybe something to check.

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Well I doubt an EGR would cause those symtoms. Is it an auto? Vacuum modulated? Maybe that has something to do with it happening in gear. I really don't know, but maybe something to check.

 

Just mentioning that the car doesn't have an EGR setup, it was deleted.

 

It is an auto, I *think* it would be vacuum modulated - it's a C4, but has been converted to full manual, reverse pattern.

 

I got this reply on another forum -

 

"tps. My car did the same thing. Yes your tps can pull the car to 6k with the tb closed. Dont ask me how"

 

Hmmm. I could buy that a hosed up TPS could hold the car at an RPM by having physically messed up plastic inside it stopping the blade from returning shut, but I'm not sure how it would cause one to rev high?

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What vehicle was it in? Had it happen once after I jump started the Formula once. Driving a friend home and all the sudden the idle launched up to 4500 or so. Got it home and pulled the battery cable and let it sit all night.

 

Hooked it back up the next morning and it ran like nothing ever happened. I'm guessing the computer had a stupid moment and pulled the IAC all the way out.

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but how could anything cause the motor to rev that high without the tb open some to pull in enough air to rev that high. No expert but do you have cruise control on the car? thats where i would think to look if the throttle body is cable operated.

 

Interesting. i'd never even thought about that but that could be the case, may have been mine as well.

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but how could anything cause the motor to rev that high without the tb open some to pull in enough air to rev that high. No expert but do you have cruise control on the car? thats where i would think to look if the throttle body is cable operated.

 

No Cruise Control.

 

I'm tracking an interesting idea concerning the turbo building pressure and forcing the tb blade open, raising the RPM, raising boost, raising RPM, raising boost...

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