Hello everyone, I have a 1985 2.8L v6 Fiero GT and it idles at about 2000 RPM (pretty sure that not normal) I tracked ot down to the IAC by mostly coverying thw hole in the throttle body and sure enough It idles fine so I bought a new IAC... andddd It still does the same thing IAC is fully open to the point where I can physically hear and feel the tiny little hole sucking a ton of air into the throttle body. I tried resetting the IAC by jumping the A and B pins on the aldl and plugged the IAC in with the key in the on position and hear the IAC wxtend fully (it keeps trying to go foward though) start the car and same **** 4k rpm Im completly stomped and want to light my fiero on fire.... any help please before i start crying while smashing my fiero with a sledge hammer?

[This message has been edited by lordxchris (edited 05-24-2017).]

When you had the IAC out did you peek into the opening to check for crud build-up? There's a seat in there that may need cleaning. If its dirty the tip of the IAC will not fully seat.
Every time you shut down the engine the IAC resets itself (plunger tip partially off the seat) so upon the next start its already in the idle-rpm position.

If you start the engine with foot off the gas and the idle goes to 2k or 4k the IAC plunger did not set properly or you've got other issues. Check all your grounds. See factory manual.

There's also a (ATS) air temperature sensor in the air filter box. Modern day version of a choke. This can richen up the mix and cause some issues.. if memory serves me correctly.

Good luck.
Spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

Thanks @spoon Ill go ahead and try cleaning it out tomorrow, the air filter isnt hooked up but i did plug the sensor in no tube or filter tho atm could this be it ?

[This message has been edited by lordxchris (edited 05-24-2017).]

Is the filter can attached to the car to create a ground? The sensor appears to have two wires coming from it....so it would seem to not need to be grounded...but stranger things have happened...especially on Fieros!

quote Originally posted by cvxjet: Is the filter can attached to the car to create a ground? The sensor appears to have two wires coming from it....so it would seem to not need to be grounded...but stranger things have happened...especially on Fieros!

Nah just chilling, it doesnt really bolt in to begin with so to speak itsnonly jeld on by the nut for the lid would make a very shitty ground if you ask me

Did you drive enough to reset the new IAC. I think you have to get it over 35 MPH to reset it. If you just bolted it in and started the car that may be why it still idles high. Cleaning the IAC port is also a good idea.

quote Originally posted by johnt671: Did you drive enough to reset the new IAC. I think you have to get it over 35 MPH to reset it. If you just bolted it in and started the car that may be why it still idles high. Cleaning the IAC port is also a good idea.

Its not driveable, it either idles to high to get it in gear or idles to low and stalls

quote Originally posted by Spoon: When you had the IAC out did you peek into the opening to check for crud build-up? There's a seat in there that may need cleaning. If its dirty the tip of the IAC will not fully seat.

Yeah, I'd say it's pointless replacing the IAC valve unless the entire passageway and valve seat has been thoroughly cleaned.

quote Originally posted by lordxchris: Thanks @spoon Ill go ahead and try cleaning it out tomorrow, the air filter isnt hooked up but i did plug the sensor in no tube or filter tho atm could this be it ?

Your Fiero has a cold air intake meaning the air going into the engine is coming from outside the vehicle instead of under the deck-lid where its hot. The ECM is expecting outside ambient air under normal conditions. Your ATS is virtually dangling in the firebox of a 2.8 furnace and the ECM is freaking out because that reading is way out of range. The ATS needs to be in the air flow stream. The 2 wires on the ATS means its grounded by the ECM directly whereas a 1 wire O2 sensor is grounded through the steel exhaust system.

Check link below for checking the ATS. This was posted by Dodgerunner a member on this forum.

http://www.gafiero.org/bbs/index.php?topic=641.0

Spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

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quote Originally posted by Spoon: Your Fiero has a cold air intake meaning the air going into the engine is coming from outside the vehicle instead of under the deck-lid where its hot. The ECM is expecting outside ambient air under normal conditions. Your ATS is virtually dangling in the firebox of a 2.8 furnace and the ECM is freaking out because that reading is way out of range. The ATS needs to be in the air flow stream. The 2 wires on the ATS means its grounded by the ECM directly whereas a 1 wire O2 sensor is grounded through the steel exhaust system. Check link below for checking the ATS. This was posted by Dodgerunner a member on this forum. http://www.gafiero.org/bbs/index.php?topic=641.0 Spoon

Thanks ill look tomorrow it rained all day but this sounds pretty likely although i have the decklid off but it still hets pretty hot in there lol