Hopefully someone can help me.

few weeks ago my fan motor went bad, so we replaced it, and in the meantime replaced the thermostat. Fixed my overheating issues. While we had it there, decided to take off the vaccum elbow and clean up into the intake manifold. Carbon just poured out. Now, I have a idle issue. Replaced IAC and reset it. Nothing. On starting, it'll idle at 1800 and kick down to a steady 1500. In drive, it's at 900-1000. I'll drive say 10 minutes and park, it'll idle at able 900-1000, then SES light will come on and idle hits 1500-1800. I have 4 codes, IAC and EGR Cylin. 1 2 3 (which was there since I bought the car 30k miles ago).

Any ideas to why it idles high after cleaning the intake and replacing IAC?

 

Sounds like a vacuum leak to me. Check the vacuum elbow you pulled and make sure it's on tight.

 

Not leaking. Sprayed Carb Cleaner around the joints and nothing. Any other ideas?

 

why arent you looking at the egr. if stuck open it would cause high idle.

 

Well i've replaced the egr once already, so I doubt that's it.. unless the line Is clogged. Any other ideas?

 

Plug the port that feeds the IAC and see if the car will run. This will tell you for 100% your not getting air from someplace other then the IAC. Then you need to watch the IAC with a scan tool to see if the ECM is telling it to open to if its telling it to close and its just not moving.

I have had cars that I had to teach the IAC Homing process several times before it took.

Open EGR valve should cause stalling not RPM increase, Remember the EGR is letting in exhaust and exhaust should have very little O2 or fuel so it just takes up spaces in the cylinder.

 

I appreciate the response. We have hooked a scanner up, and when the gas pedal is depressed, the IAC is opening, just not at Idle. I am assuming that's gonna be a costly repair, it always is when you need a dealer to do something (program the computer). Thanks.

 

It is normal for the IAC to open as you press the gas. There is a transition going on as the air supply to handed off from the from IAC to the thottle plates. As you press harder on the throttle the IAC should start to close. Its been awhile for me but somewhere around 20% throttle the IAC should be back to Zero. Did you plug the port to see if the car dies or even changes RPM?

I am not sure but I think the Snap-on scan tool can flash Vin numbers. I think that is all a used PCM should need to work with your car, of course you need a PCM from the same year and drive line as you. Any place that can tune your car can definitly flash the VIN. I do not own a 94 and have never done this but I would think a few phone call might be in order. Hit up a car show or a cruise and find out who works on 94 PCMs if the yellow pages fail you.

 

Is there an idle relearn he can do. A lot of cars have issues with the idle air after cleaning the TB or intake out and i would imagine its required if you change the IAC. Google for a relearn procedure many times it can be done with out a scan tool.

 

Trust me, I've tried every relearn technique under the sun. Nothing helps it. As far as the new ECM, I found someone to sell me a Reman + Flash for $70, vs $90 for the ECM + $135 for Dealer Flash. I'll let you know if it works, in the meantime, I am pondering what else it could be. I haven't been able to plug the IAC yet to see if it stalls, but given it does, it means that air is passing through it. If it doesn't stall, that means it's getting air else where, right? And how would I go about plugging it.. ? Just remove it and stuff it with something? It's in an odd position.