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IAC,maf, crappy tps

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Old 03-29-2011, 08:20 AM
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Default IAC,maf, crappy tps

Last night I punched it while I was way out in the middle of Mexico and when I let off the idle dropped to 500ish. I had the scanner hooked up and was logging anyways. I did get a little detonation around 46-5400rpm. When the idle dropped the maf was reading 3g/s. Also I took my iac out last week and cleaned it but it was stuck after being pressed in once. Shouldn't this push back out? The TPS was replaced awhile agO with a cheap advance auto brand but my scanner won't read tps voltage. After the low idle drop I continued driving and then jumped on the highway to head home. When I let off and out it into nuetral te car would rev up to about 2,000. The pedal and cable is not sticking. So who's the culprit?
Thanks guys!

Last edited by ffrh911; 03-29-2011 at 09:56 AM.
Old 03-29-2011, 04:54 PM
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Old 03-29-2011, 05:58 PM
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the iac is controlled by the car computer while driving . you might have a bad one but i doubt it .
have you added anythign else here of late or any other mods htat might act up ?
did you get any gas while in ol mexico ?
the tps a trick with it is to tap on it lightly also make sure the gasket is still there .
have you took apart any of the componets ?
sorry for all the questions just trying to contemplate the ifs . try to give some more info on another ride . check your plugs , wires, conections , anything easy to get to before openeing it up .
could have a 02 that is not right .
Old 03-29-2011, 06:07 PM
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Its most likely the IAC valve, they are easy to mess up when taken out to clean..........or your TB is not closing all the way when you come off the pedal. Only way for an engine to rev up...air is getting in that shouldn't, period. Vacuum leak can do it too, but since you were messing with the IAC, its probably that.

The detonation, if it happened while at WOT, can be the MAF.

Go buy a new IAC valve, put it in, if thats it you're good. If its not it, return it for a refund. Just tell them its the wrong one and it doesn't fit. I've done this a million times with all kinds fo parts.

.
Old 03-29-2011, 07:56 PM
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Isn't the iac suppose to spring back when pressed? It sticks all the way when pressed.

Just the exhaust that it's not fully tuned for. The gas was bought at a sunoco.
The problem is always when I put it in nuetral and let it go to idle. Then it either sticks up or surges down.

Yes the gasket is still there. I have taken the throttle body apart recently but the surging down to 500rpm has happened before.

How come some scanners Dont measure tps voltage?

And a iac is 100$ from the local auto parts store. I'll have to wait a little while before I can get it.

I also tuned the timing down a notch and checked it and there was no detonation.
Old 03-31-2011, 10:33 AM
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