I have my new motor in the car and after it warms up it idles from 800-1400. It doesn't do it all the but about 90% of the time. I have changed to a edlebrock intake manifold and tb. Has anyone had a problem with one of these? If I turn the idle up to 1600 rpms it idles smooth. I've checked all the vaccum lines, tb gasket, im gasket, swapped out my idle air control valve. Any ideas? I don't have coolant going to my tb or idle air control valve. I have never had coolant going to the tb and my buddy at work doesn't have coolant going to his ICA and his b16 idles fine. Any suggestions?

 

up

 

if im not wrong, the IACV is dependent on coolant temp. Try hooking the 2 lines back up.

 

Spray throttle body cleaner around the TB and the IM. That is were i found my fluctuating idle to be. Also bleed your radiator fluid. It isn't that, but sometimes it smooths things out a bit. 90% of the time idle probs lie in vaccum leaks.

 

did you mess with the tp sensor adjustment?

 

Doesnt the fast idle valve and IACV work off the coolant temp? Like on cold starts it will activate the IACV? Maybe because u have no coolant in there it is always letting air bleed through maybe thinking the engine is cold.

 

did you mess with the tp sensor adjustment? no I haven't

Any suggestion on what I should try?

 

If you have a multi-meter handy, check the TPS voltage - @ idle: .45v.

If you disconnect the IACV on a warm engine, does the idle drop, but become stable? What does it drop to? It sounds like either the idle air adjustment screw or the throttle blade stop screw has been messed with, or rather not setup correctly, and allowing an un-metered source of air to enter the manifold, which usually leads to the whole decel/TPS closed/fuel cut strategy the ECU uses causing a hunting idle.

 

thats why i dont mess with anything that has the jg name on it

 

Voltage at full throttle is 4.5volts. I have played with the idle screw and throttle plate screw and as soon as it gets warm and I turn the idle below about 1200rpms it starts idling up and down.

 

If your T-body still has the FITV, check to see if it has rattled loose. Just a thought

 

I had this same problem last year it was the fast idle valve.

like said above shake it and see if its broken.

 

I swapped the fast idle for one i know works and it didn't change anything.

 

I'm sure you guys know the FITV, fast idel thermo valve, can simply be tightened back up. Remove the FITV, take the flat plate off the end, 2 8mm nuts, use a flat head to turn it clockwise to retighten, reassemble and call it done. No need to replace it.

Now if its the IAC, yeah, replace it

 

check this,

fast idle valve,
check to see if TPS and IAC sensor are plugged backwards ( they uses the same prng harness)
check the ignitor ground ( on top of the thermostat housing, if loose, your idle will go erratic)

stan

 

thats weird, my IAC is a 2 pin plug,and my TPS is a 3 pin plug

 

where is the fitv??? and how do you check the iac??? sorry to steal your thread but im actually having the same problem with by b18c1 when i installed my 440's and 68 str throttle body.

 

is your valve bad ??? because my ls manifold had a fluctuation in its idle due to the valve which by the way is way overpriced i made a new fix for $0.65

 

Lets keeps this thread going I would really love to know what the answer to this iradic idle problem is I also had the same problem last year and could never figure out a solution for this even after a new iacv and 3-4 coolant flushes..
Heck I wonder what would happen if you never even hooked the coolant lines up to it..??

Adi

 

Good god, Get a book from autozone. It will show you where this stuff is (has pics) and how to properly check it. Its not the best manual out there but it sound like it would be a good start for some. Get the book for the motor thats in the car. Not the book for the car you drive.

 

ttt

 

you can remove the FATV entirely. The ECU doesn't care if it's there or not. Just seal off the holes.

 

My exhaust cam gear was loose and was moving from 0-8 degrees retart. I fixed that and it idles pretty nice now. My tps voltage at idle is slightly high .467 could this be a problem at all. I have it idling at 900 now and every now and then it will go down to 700 for a sec and then back up to 900.