IAC Questions

[87TNGT]

i have an 87 GT that so far ive removed the a/c and smog pump and put on
MAC 1 5/8 shorty headers with an offroad H-pipe and 2 chamber Flowmasters...im having idling problems that have been there since day one....sometimes it idles great...then it will idle kinda high(1200-1500 rpms) then sometimes it will surge from 1200 down to below 500 rpm and if i come to a stop it will die...ive tried the idle reset and it didnt help at all so my question is what will happen if i simply unplug the IAC?...will it affect peformance or drivability?...reason i ask is ive seen several engine setups with aftermarket intakes and throttle bodies that dont have it installed so is it really necessary to have it hooked up?...it has a new IAC on it but i dont know how long ago it was put on

 

[PUNISHER RACING]

if you pull it it should die, try pulling the iac motor off and cleaning it as well as tb opening

 

[bloopbloob]

i'd check for codes first, but i guess cleaning it would be a good start also

 

[HISSIN50]

The IAC functions as a choke would on a carb. You'll have issues with cold starts and possible issues with rolling stalls. This all depends upon how high you've set your static idle.

I'd do what I can to fix the issue. I'd go over it again, lookin for vac leaks.

Good luck.

 

[jrichker]

See "Surging Idle Checklist for help with all your idle/stall problems. The first two posts contain all the updates to the fixes. I continue to update it as more people post fixes or ask questions.

 

[87TNGT]

See "Surging Idle Checklist for help with all your idle/stall problems. The first two posts contain all the updates to the fixes. I continue to update it as more people post fixes or ask questions.

i tried all the tips in that thread and it did nadda.....i think my IAC is shot hence the reason i was asking if its drivable without it hooked up...right now im on a rather tight budget due to housing issues and some other financial things and was wanting to know if it would hurt anything if i drove with it unhooked for a couple weeks at the most....but thank you for posting that link it was very helpful

 

[jrichker]

You were able to sucessfully set the base idle to 600 rpm and it held steady?

You didn't get any codes when you dumped the codes?

 

[87TNGT]

You were able to sucessfully set the base idle to 600 rpm and it held steady?

You didn't get any codes when you dumped the codes?

ok let me rephrase my answer LOL

i had the base idle down to 600 and it held steady...but when i plugged the IAC back in it started the surging again after about 5 minutes of driving

as for dumping the codes im half scared to as so far ive noticed that just about every item on this 100K mile car is the original sensor or item....im scared of what its gonna tell me....also i dont have a test light all i have is a digital volt/ohm meter

 

[PJB]

All you need is a piece of wire to pull the codes and watch the CEL on the dash flash.

 

[jrichker]

The reason the Surging Idle Checklist doesn't work every time is because people skip steps and don't check all the stuff in it. It is a list because I can't be there to see and hear what is happening and then say check this or check that.

Fear will keep you from finding your problem. It won't make it go away.

A test light is a small 12 volt bulb like a dash light bulb. You solder two wires to it and cover the solder joints with electrical tape or heat shrink tubing. That should not be too expensive or to difficult to do.

 

[87TNGT]

ok i scanned it at work today using an INNOVA OBD 1 scanner and found the following codes

KOEO: 23....memory codes 34 and 63

KOER: 21, 23, 41, and 91

everything i read seems to point to a faulty TPS and O2 sensors

disregard the CTS code as i replaced it about 2 weeks ago so i know its good

guess ill be replacing my O2's and TPS in the next couple days