edbro

I cleaned the IACV yesterday, reset the computer and drove it around for about 15 miles. All was good.

Today when I went to start it, it would not idle cold. After warming up it was fine. But, my problem now is that when at idle with the AC on, it will idle at 500 and either the AC stops working or the idle will surge fairly rapidly between 500-1000. I drove about 40 miles around town today. Mostly it was surging but towards the end, I noticed that the idle was smooth at 500 but the AC was blowing warm while at idle. If I turn the AC off the car idles around 750 fairly smoothly.

Any ideas?

Lexmex

I can't say much about the AC offhand directly, but with regard to your engine RPMS I have seen this engine behavior before when I reset my CEL after a fuel gauge issue. Was with my father coming back from the track and we put on AC (hot summer nights) and when we left the taco place we like to go to, I wasn't aware of the drop in RPM at a dead stop, but I do remember the RPM flying around really nutty at the light, even shutting the entire vehicle off once (P0171 error), but started back up. Only thing I did was reset CEL and drive without AC on the way home (about 5 miles) and then the next day about 15 miles or so down to our favorite Japanese place on the south side of the city. Later, when we left it was about 80 degrees outside and as I got on to the expressway, my father turned on the AC and no problems, not even on regular streets. I think that the adaptive learning is definitely playing a role there. Probably would recommend, if possible (I know it gets hot) to drive a little longer without the AC on to let the ECM get better orientation.

edbro

This problem never did clear up. I'm sure the AC cutting off is due to the low idle.

I just took it out for another spin and I got my first CEL. The code was P0120, Throttle Position Sensor. What's that? I assume I don't have something aligned properly?

Edit:
I just did a forum search (should have earlier) and got some clues. I will check the throttle valves for sticking. I guess I need to tear this all down again and reassemble.

edbro

Okay, I'm at a loss here. Yesterday I took it all apart and reassembled. Everything looks okay. But, today it still wouldn't idle cold and later it threw another CEL. I haven't had this one read yet but I assume it will be the Throttle Position Sensor again. I verified that the throttle valves move freely when I move the cable.

What are my options here? Is this an assembly error on my part? Is the TPS the black electrical coil that sits on the front of the IACV? I did remove that for the cleaning and I ensured that the little metal washer inside was still there on reassembly. I don't see any possible adjustments in that. The metal stud moves freely. I have checked for air leaks but there doesn't seem to be any.

I'm about ready to make an appt with a mechanic but I want to make sure there isn't anything else I could look at before I do that.

Lexmex

TPS is actually on the right side of the of the throttle body unit. There is a black connector you can see the blue arrow is pointing to and behind it is the TPS. That code you picked up the other day is either only relates to the TPS (not something else like an oxygen sensor or something like other codes sometimes do).

I haven't played around with the TPS and my work on the IACV valve is limited to spraying in the holes, as I have never had an issue where I had to completely disassemble the IACV, so I don't know I can offer much more advice on it without seeing it firsthand.

edbro

Hey, did you guys know that it is possible to install the black electronic module on the front of the IACV upside down? Well, you can and it will mess up your idle. A "friend of mine" did this and had surging idle. (Where's the Embarrassed smilie?)