1992 Toyota Celica RPMs shoot up when car starts

Tiny
POZOBYT
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  • 1992 TOYOTA CELICA
1992 Toyota Celica 4 cyl Front Wheel Drive Automatic

whenever I start my car, the rpms just shoot up really high without me touching the gas or anything.

what could cause this?
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Monday, December 14th, 2009 AT 10:52 PM

16 Replies

Tiny
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  • EXPERT
Hi there, this is a voltage spike problem, check the earths and both battery terminals are clean and tight, start here,

mark (mhpautos)
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Monday, December 14th, 2009 AT 10:56 PM
Tiny
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I just wired up a new car stereo straight to the battery, could this be the problem?
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Monday, December 14th, 2009 AT 11:03 PM
Tiny
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Did the tach do tis before the stereo was wired in? If not you know where to start looking.

Mark
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Monday, December 14th, 2009 AT 11:53 PM
Tiny
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No it didn't, I disconnected the ground to the stereo and it didn't fix it.

Could it be a bad tps?
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Tuesday, December 15th, 2009 AT 12:13 PM
Tiny
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The taco signal comes from the coil, just make sure that the battery is clean and tight, check with the stereo power & earth off, if it was ok before it must have something to do with what was done with the wiring for the radio, try this and get back to me, I will look up the wiring for this and see if I can see anything else wort looking at.

Mark (mhpautos)
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Tuesday, December 15th, 2009 AT 3:23 PM
Tiny
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Okay I tried completely unplugging the power and ground from the stereo, and it seemed to fix it. The idle was normal. But after I turned the car off and turned it back on again, the problem started again.

When I revved the engine a couple times, they rpms dropped but it still idled around 2000 rpm.

And I tried driving it down the road, and the rpms went to normal when I shifted to drive, but when I accelerated, the rpms raised to about 3500, and the car shifted at 15 mph, and the rpm went down, but it usually shifts at 30 mph, at 3000 rpm.

Also, when I was driving, and let off the gas, the rpms stayed the same and the car didn't slow down.

After I drove it and brought it back home, and restarted the car, everything seemed normal, then I restarted it again to make sure it was okay, and it idled high again.
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Tuesday, December 15th, 2009 AT 3:45 PM
Tiny
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Ok, I have slightly miss understood your question, I was thinking that the tacho was peaking and giving a false reading against actual engine revs, (this can happen with a power & earth problem at the Tacho)

so if the actual revs are high you will have to check the idle control system and the throttle body, the TPI sensor won't cause this alone, as it is only a reference signal to the ECU for throttle percentage, if this is faulty you normally get a bogging down and no response, clean the throttle body, check for vacuum leaks and check the idle control system.

Mark
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Tuesday, December 15th, 2009 AT 3:54 PM
Tiny
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Where is the throttle control locacted?
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Tuesday, December 15th, 2009 AT 4:30 PM
Tiny
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As you have located the throttle butterfly, don't use DW40, you can get a dedicated throttle body cleaner, make sure that all the black fuel & carbon residue is cleaned off and give the lip of the butterfly valve a clean as well, see how this goes, you may have found the problem.

Mark
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Tuesday, December 15th, 2009 AT 5:27 PM
Tiny
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Okay thank you.

Do I need to clean the wires that pull the throttle open and closed also?
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Tuesday, December 15th, 2009 AT 5:40 PM
Tiny
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No, that should be ok, just make sure that the adjustment is ok, that is the butterfly shuts off and there's just a tiny bit of slack in the cable,

Mark.
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Tuesday, December 15th, 2009 AT 5:43 PM
Tiny
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Okay, I cleaned it and it still isn't shutting all the way. Is there a way to tighten the tension on the cables that open and close the throttle? Or would that be a bad idea
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Tuesday, December 15th, 2009 AT 6:31 PM
Tiny
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If you look at the cable where it is attached to the back of the manifold, I think there are 2 10mm bolts holding it in place, this is where you can adjust the cable, let me know if its not the same.

Mark
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Tuesday, December 15th, 2009 AT 7:42 PM
Tiny
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I can't find them.

After I cleaned the throttle it helped a little bit, but it's still sticking open a little bit and I'm idling at 2000 rpm.

I can't find where to adjust the cable, but I'll take a picture of it tomorrow when it's not dark and upload it.

It idles around 1200 rpm normally, and when I push the throttle shut it's fine, but like I said, after I rev the engine, it shuts back to the same spot. A couple centimeters from being where it should be.
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Tuesday, December 15th, 2009 AT 8:09 PM
Tiny
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I will look on line for something to help, we will sort this out.

Mark
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Tuesday, December 15th, 2009 AT 8:18 PM
Tiny
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Okay cool.

Thanks so much for helping me out.
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Tuesday, December 15th, 2009 AT 8:22 PM

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