Im still having a bit of a rough idle issue. Replacing plugs, wires, dist cap and rotor helped a lot but it will still suddenly go to a really low idle and occasionally die, especially if the AC is running (yes, we still need to use the AC here in Cali). Im thinking maybe its the IAC. My manual says this type of IAC is called "dual taper" or "Type II" and I should be able to adjust the pintle length by turning the pintle clockwide while pushing it in. Well, it doesnt move at all no matter what I do. I havent taken vise grips to it but have tried as much twisting and turning as is possible bare handed.

Do I need to use hand tools to turn it or is this an indication of a problem? Zip has the part for $120 so I imagine it would be 50% higher at a local store. Id like to find out for sure if its bad before i just toss a new one in (especially at christmas time when Im broke from gift shopping already).

The manual says not to soak it in anything but I gave it a light squirt of WD-40 to see if it was just lightly jammed and it made no diff.

As we speak Im sitting here with my pintle in my hand so any help would be greatly appreciated!!! (that didnt sound so good did it? :lol: ) :blueangel:



[Modified by DarkHalo, 10:35 AM 12/15/2002]

 

I have the same problems with the idle and have been messing with the IAC a little. I have one of each. The push kind takes a fairly good amout of force and a little side to side movement on the pintle. The twist kind takes a lot of twists to get any change and it helped to hold the spring down while twisting.

I still think my problems are iac/computer problems. With the iac unhooked, the idle is stable. Plug it in and the idle goes to crap.

 

Now THATS interesting! I believe the IAC is to help with cold weather idle problems but here in Cali thats not usually an issue. Today for example its a balmy 70 something out there right now. Ill try running it for a while unkooked to see what happens. Of course the gasket fell apart when I took it off and its not likely to be available locally on a sunday but it looks like generic gasket material will work ok. Thanks for the info! :blueangel:

 

Seems to me you are in the right neighborhood.

Couple of thoughts.

With a mirror and or flashlight, does the area around the throttle body IAC housing look clean. If you've never cleaned the throttle body, now may be a good time. After cleaning, follow procedures for setting minimum idle. Part of this procedure is to extend the IAC valve, set minimum, then allow computer to position the pintle.

At operating timeperature, normal idle, the computer should be adjusting the pintle count for smooth idle. When you hit the A/C, puter gets heads up, delays A/C on (about .5 second) until it can increase idle compensating for the compressor drag.

The computer MAY be correcting for A/C however if the air passages used by the IAC are partially clogged, the the only source of air would be the gap between throttle plate and the housing. Not enough air for normal idle.

Vacuum leak is another possiblity. Partially open EGR valve is another.

Good luck.

dlmeyers 90 coupe zf6 3 speed shocks

 

:iagree:
I would clean everything and try to reset and relearn your idle settings. Vaccum could also be a problem maybe even around the IAC if your gasket was hardening and coming apart.

 

Go to Autozone and get a new IAC for $35, it works great.

 

I have a sim problem - sometimes my '92 is rough starting, until it warms up and the it usually is OK. What do you do to disconnect the IAC ? Do you run with it that way, or just to trouble shoot?

 

I couldn't get it to idle but had to drive it to the shop. It would idle with the IAC unhooked from the bottom of the throttle body and I drove it that way to the shop.

 

Oooops, sorry, I have no answer to your question. From the header, I got the impression you had a question specific to me (I have been called somewhat laid-back at work)............(I couldn't resist)...... :crazy:

 

Any tips on how to clean the TB and IAC?

$35 from AutoZone? Wow - at that price, I just might get one for the heck it!!

 

:iagree: I looked online and the average price was $120 for it! Funny thing is I was at an Autozone earlier today to get a gasket for the IAC. Of course they didnt have it so I just got a sheet of generic gasket material.

Above it was suggested to just disconnect the IAC unit electrical connector. Well, I did that and it sat there idling at 2000 rpm till I turned it off....

For that $35 price tag Ill prolly just grab one at the Autozone tomorrow. :blueangel:

 

Throttle body can be sprayed with cleaner and wiped with a rag, I prefer Deep Creep by seafoam available at Napa. It not only breaks up carbon but lubricates and protects at the same time. The IAC can be removed and cleaned with the same stuff a stiff toothbrush cleans most everything off after letting the cleaner soak a few minutes. There are other good cleaners as well but this is the onle I have had the best luck with. I use it everyday at work.

 

If you do a forum search you will find lots of good info on this. Yep 35 bucks AND it comes with a gasket! :)