DTN

I have a problem with the Air Conditioner. If I turn on the car with the A/C on, or I turn on the A/C shortly after I turn on the car it works fine and it idles at about 1100 RPM. The problem occours if the car is warmed up and the A/C is turned on. The problem is that the idle drops very low, about 500, and shakes the entire car, then up to about 800RPM . The Idle is fine if I turn off the A/C after the car is warmed up, but If I turn it on after that, the idle drops and steady's at about 800 RPM. It won't pick up 1100 RPM again.

I need to get this fixed. I've replaced the front o2 sensor, I've replaced my TPS twice, I've replaced the MAF sensor and I've replaced the IAT sensor. I think it may be a problem relating to engine load. I don't really have a good place to start. I had all of my eggs in the MAF and IAT basket.

I've got no CELs, just a low idle when the A/C is turned on after the car is warmed up. It idles fine with the A/C on, but if the A/C is turned off and then turned back on, it won't idle right. What should I check or replace?

Coal_forge

How about the ac clutch? When I did have air conditioning I remember at idle it the ac clutch was slightly disengaged.

DTN

I can feel when the AC clutch engauges and disengauges. It puts a load on the engine. When the AC gets too cold, it removes the AC clutch grip and the idle goes back to normal.

How can you check the AC clutch?

Any other suggestions? Would it be worth it to investigate the ECT in this case? My temp gauge is in the middle and my OBD-II readings are right around 200.

dddude55

^^ I forget who said it, it's in a quote in someones signature.

"The stock temp sensor has 3 settings: Cold, Normal, And you just toasted your engine!"

DTN

There are 2 sensors. he was talking about the gauge. I'm wondering about the OBD sensor.



It dosn't appear to be off according to the readings, but it's part of troubleshooting high idle problems. I really could use some suggestions.

zoned019

So, with the AC on the car idles at 800 RPM instead of 1100?

That's it?

I think that's normal man. At least I know both the tibs I have owned have done it.

DTN

no, when I turn the car on with the A/C on it acts as it should, it idles at 1100, and runs fine. i turn it off, the idle drops to 900RPM and when I turn the A/C back on, the entire car shakes, idle drops down to 400-500 RPM and then slowly raises back to 800 where the idle stays rough and shakes the car.

According to HMA service, the idle is supposed to raise to 1,100RPM when the A/C is turned on. It used to do this and it stopped. I'm trying to figure out this problem. It's not even slightly normal and it's quite embarrassing.

yamaha

Sounds like a bad IAC to me, did you check the new one?

DTN

I replaced that less then a year ago. I would think it's still good. If nothing else comes of this troubleshooting, I'll get another one. The fact that the idle can be controlled leads me to believe that it's ok. It's as good as replacing any other part though so I can give it a try.

Anything else? I'm really frustrated and ready to change anything. Has anyone heard of an ECU going bad? Is that unheard of?

tib _500

holly crap this is the EXACT same problem ive had with my car. I didnt have it until i swapped engines. the AC components are exactly the same and ive changed everything you have changed (even both o2 sensors). still nothing. heres my list of things i also got but didnt help: tune-up, coil, condensor on the coil(just a guess), grounds, removed and cleaned fuel rail and injectors, changed Hvac controls (since my dash had beedn broke before), and re-checked all vacums to A/C and all the other lines.

the only thing i didnt mess with was the TPS but i put a Kiefco on after it was swapped
so im at a loss as well