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 Message Boards » » Running the A/C messes up the engine idle Page [1]  
esgargs
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So this is something that started today. Basically, when I run my A/C, it cools perfectly and everything, but periodically it slows down the engine idle to a very low RPM. The cooling stops at that point, and the computer tries to rev the engine up a bit after that. A little while later, the cooling starts again, but the cycle repeats itself. Everything runs smoothly if I turn off the A/C.

What could be the issue here?

5/9/2006 9:04:12 PM

SaabTurbo
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The A/C probably swallowed a muffler bearing....

5/9/2006 9:06:27 PM

esgargs
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What does that mean?

5/9/2006 9:06:52 PM

SaabTurbo
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absolutely nothing

5/9/2006 9:07:49 PM

zxappeal
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sticky IAC.

Does the engine rev a little when you start it cold? Or does it start and stay at idle from the moment you turn the key?

5/9/2006 9:29:13 PM

esgargs
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it revs a little for half a minute or less when I start it cold.

Is that bad?

5/9/2006 9:32:44 PM

esgargs
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so it fixed itself




[Edited on May 12, 2006 at 2:46 PM. Reason : :]

5/12/2006 2:46:22 PM

zxappeal
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Quote :
"it revs a little for half a minute or less when I start it cold.

Is that bad?"


No, that's not bad at all. Most engine management systems rev the engine a little on startup.

That indicates to me that the IAC (idle air control) is working correctly.

5/12/2006 2:58:45 PM

esgargs
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5/12/2006 3:15:29 PM

Rudy
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does your car have a second, electric fan? might be fucked up...that'll do it

5/12/2006 5:01:47 PM

esgargs
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yeah

it does have an electric fan at the front. I don't know if it's the second fan, because I have never seen another fan...but I have never seen the electric fan run.

5/12/2006 7:04:01 PM

Rudy
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probably only has one then, i know shit about foreign cars... wonder if the ac pump bearing is going out loading the engine down a bit or some shit...

5/12/2006 8:14:26 PM

esgargs
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hmmm

it's a Ford.

and I think you might be right.

Are the bearings expensive to fix?

5/12/2006 8:43:10 PM

zxappeal
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I think both of you need to stop right now before you get yourselves into trouble.

5/12/2006 9:15:32 PM

esgargs
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?

then what's the problem, sir

5/12/2006 9:19:24 PM

zxappeal
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Sounds like high pressure side is building too high, and the compressor's laboring. Possibly due to a radiator fan not working like it should and not enough heat dissipation through the condensor.

5/12/2006 9:25:07 PM

underPSI
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personally, it sounds to me like the car is running normal and the difference of the rpm's comes from the compressor cycling on and off.

remember who we're dealing with here.

5/12/2006 9:41:19 PM

zxappeal
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^Very good point.

5/13/2006 2:53:51 AM

esgargs
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Why would the compressor cycle when it is turned on to max cool? Not to mention that I always thought that all the climate control does is mix hot air with cool

Besides, the rev speed went down so much that at times the voltage dropped considerably..

[Edited on May 13, 2006 at 3:24 AM. Reason : .]

5/13/2006 3:17:04 AM

underPSI
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max cool just turns on the recirculate mode.

5/13/2006 8:42:36 PM

esgargs
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I meant the temperature, genius.

5/13/2006 8:52:48 PM

drunknloaded
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Quote :
"personally, it sounds to me like the car is running normal and the difference of the rpm's comes from the compressor cycling on and off."

5/13/2006 10:02:12 PM

esgargs
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well, the problem recurred for a while, but seems to be alright now. Could it mean that my A/C is dying?

6/7/2006 2:52:36 AM

zxappeal
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No cold air means your ac is dying. That and loud scraping or screeching or whining noises with periods of no cold air, followed by cold air and such...

Bastard prolly needs a top-off of refrigerant...

[Edited on June 7, 2006 at 2:54 AM. Reason : more refrig]

6/7/2006 2:53:43 AM

esgargs
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well, there were no sounds but the cold air did stop flowing if I brought my car to a halt.

6/7/2006 2:54:35 AM

zxappeal
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Yeah. You prolly need a top-off. Gotta keep that compressor up to speed and keep air flowing across the condenser in order to supply the evaporator with enough liquid refrigerant.

Could also be a sticky expansion valve...

[Edited on June 7, 2006 at 2:58 AM. Reason : exp. valve...]

6/7/2006 2:57:39 AM

esgargs
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does that explain why the pump would rev down the engine to almost dead?

6/7/2006 2:58:30 AM

zxappeal
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nah...not really. Well yeah, if the expansion valve is sticking closed, then it can bog down the compressor...it's deadheading against a closed valve. Can't really tell squat unless I put my manifold gauges on there to check system pressures. If it's intermittent, I might not be able to tell...until it happens.

6/7/2006 3:01:45 AM

esgargs
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is that the same valve as the one you mentioned previously?

I have observed that this happens only when I don't use the A/C for extended periods of time (a month).

6/7/2006 3:03:20 AM

zxappeal
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Yeah. Could be. Pain in the arse to fix, unless this is actually a CCOT (clutch cycling orifice tube) system, but I bet it's not.

I did Duke's brother's about 2 years ago.

For your car, dealer installed AC is expansion valve.

Factory installed is orifice tube.

[Edited on June 7, 2006 at 3:18 AM. Reason : ...]

6/7/2006 3:15:59 AM

esgargs
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I guess I'll just have to find a new car or do without the A/C

It's factory installed.

[Edited on June 7, 2006 at 3:19 AM. Reason : .]

6/7/2006 3:19:02 AM

69
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^
1. you can't afford a new car
2. you're too much of a pussy to not use the ac
3. get the fuck over it

6/7/2006 7:32:24 AM

El Borracho
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that's what you get for buying a gay ass mustang

6/7/2006 8:11:03 AM

esgargs
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haha

Are we talking about what I can and cannot afford here?

6/7/2006 1:23:20 PM

MattJM321
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he thinks he's baller

6/7/2006 3:49:24 PM

69
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but everyone else thinks he's a fag, that touches waitresses

6/7/2006 4:32:14 PM

slowblack96
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well when you compresor clicks on it makes the engine have to work harder.it might only cut the engine speed about 150 rpm depending on how well you maintian your car. i.e tune ups fuel injection services and so on. there is nothing to wrrry about as long as everything has been maintained well

6/7/2006 6:27:14 PM

 Message Boards » The Garage » Running the A/C messes up the engine idle Page [1]  
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