Experiencing issues at idle with A/C on and A/C blows from hot to cold
07-11-2010, 11:23 PM
#1
1st Gear Member
Thread Starter
Join Date: May 2007
Location: Greenville, Texas
Posts: 140
Experiencing issues at idle with A/C on and A/C blows from hot to cold
I'm hoping someone here has experienced similar symptoms and can help me resolve my problems.
My car idles oddly, and when the A/C is on the tach bounces from 400 to about 1k rpm. The tune for it is programmed to 750 I believe, and if the air isn't on it usually stays pretty consistent at that point. But when I first start the car it always starts and dips way down almost dying, and then sits at 750. Doesn't matter if it's cold or hot, it never sits and idles higher, like it did when it was stock and cold start up.
Either way, it's even worse when I try to run my A/C. The A/C being on causes the tach to bounce significantly and even makes a rumbling/vibration noise if I'm in park or sitting still. The vibration/rumbling noise almost sounds as if its behind me though.
Today I finally replaced my fuel filter and I bought some cans of r-134a to charge my A/C system, but when I connected the hose with the gauge attached the gauge went to a max indication so I didn't mess with it for fear of damaging the system.
While actually driving down the road with the air on it will blow plenty cold and work the way it should. If I sit still at a light or at start up, it turns hot and then the idle issues show up. If sitting still and reving the engine the air still blows hot.
Thinking about making some calls tomorrow to some different shops about the A/C system but I thought I'd see if anyone here has something to offer up. Some quick searches have turned up things about the throttle position sensor and other parts of that system.
I have also died twice recently. Once today I was doing about 30 and tried to set my cruise control and it died (had the A/C running) and the other day I was getting on the interstate and we came to a stop and it died.
The car is automatic, 2006, about 70k miles. Running an 87 Perf. tune.
Thanks!
My car idles oddly, and when the A/C is on the tach bounces from 400 to about 1k rpm. The tune for it is programmed to 750 I believe, and if the air isn't on it usually stays pretty consistent at that point. But when I first start the car it always starts and dips way down almost dying, and then sits at 750. Doesn't matter if it's cold or hot, it never sits and idles higher, like it did when it was stock and cold start up.
Either way, it's even worse when I try to run my A/C. The A/C being on causes the tach to bounce significantly and even makes a rumbling/vibration noise if I'm in park or sitting still. The vibration/rumbling noise almost sounds as if its behind me though.
Today I finally replaced my fuel filter and I bought some cans of r-134a to charge my A/C system, but when I connected the hose with the gauge attached the gauge went to a max indication so I didn't mess with it for fear of damaging the system.
While actually driving down the road with the air on it will blow plenty cold and work the way it should. If I sit still at a light or at start up, it turns hot and then the idle issues show up. If sitting still and reving the engine the air still blows hot.
Thinking about making some calls tomorrow to some different shops about the A/C system but I thought I'd see if anyone here has something to offer up. Some quick searches have turned up things about the throttle position sensor and other parts of that system.
I have also died twice recently. Once today I was doing about 30 and tried to set my cruise control and it died (had the A/C running) and the other day I was getting on the interstate and we came to a stop and it died.
The car is automatic, 2006, about 70k miles. Running an 87 Perf. tune.
Thanks!
07-12-2010, 06:05 AM
#2
3rd Gear Member
Join Date: Dec 2006
Location: Colorado
Posts: 944
The first thing I would do would be to reflash the 87P or install a different tune to see if that cures it.
Yeah, the engine should idle high when you first start it in the morning, then it should settle down.
My original 91T tune would lock the doors when backing out of the garage. Not supposed to do that.
Also, the rpm's would drop down way low when I put it in park, with or without AC.
Hopefully it's just a tune issue.
Good luck.
Yeah, the engine should idle high when you first start it in the morning, then it should settle down.
My original 91T tune would lock the doors when backing out of the garage. Not supposed to do that.
Also, the rpm's would drop down way low when I put it in park, with or without AC.
Hopefully it's just a tune issue.
Good luck.
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