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Aveo is driving me nuts!

Hope someone can give us a direction on what to do.

I have an Chevy Aveo 2007 automatic and just had it:

  • replaced with new spark plugs
  • changed oil
  • cleaned filter
  • changed trans fluid
  • new timing belt
  • new a/c compressor (since the old one broke)
  • refilled with refrigerant
  • new a/t filter
  • cleaned idle sensor
  • increased rpm
  • computer checked several times but no errors detected

What i can’t understand (as well as half this city’s mechanic) is why the a/c compressor keeps on disengaging/reengaging when the car is on idle (worse when on reverse). When it does that the engine chokes and almost/sometimes dies. This only happens if i stepped on the brake/not moving.

This never happened before so I know it isn’t normal. Would this kill my compressor if i leave it like that?

I am about to set a lighter on it.

I believe the compressor is supposed to engage and disengage. It isn’t supposed to be constantly engaged when you have the a/c on. I believe it is only supposed to kick on when the pressure in the system gets to a certain point.

I do know, with a degree of certainty, that when the engine needs more power, the engine’s computer disengages the a/c compressor automatically. I know this because I have heard Click and Clack say it several times on their show when some nut calls in to tell them he is turning off his a/c when he needs more power.

Ah… but is it normal to keep on engaging/disengaging like every 2-3 seconds? this never happened before and i am worried that it might damage something because my rpm needle goes up and down when it does so.

The compressor is not supposed to cycle every two or three seconds, that needs to be fixed, but the reason it stumbles is because you turned up the idle.

There is no idle adjustment, there is a throttle stop set screw, but it is only there to protect the throttle body, it is not an idle adjustment. If you “adjust” this, then the computer thinks your foot is still on the gas so the ECM does not attempt to control the idle through the IAC.

“Increased rpm?”

That’s bad, and I believe whoever did it has contributed to the problem, not the solution. The computer will adjust the idle speed as necessary, such as when the AC compressor cycles on, but neither you nor a mechanic should attempt to adjust the idle speed.

An AC compressor that cycles too frequently is often a sign of low refrigerant. Perhaps there is a leak.

Or it could be something else. A vacuum problem comes to mind since you say this only happens when you’re stepping on the brake.

I suggest you take the car to a shop that specializes in automotive AC systems, and let them make it work correctly.

But you need to reverse that “increased rpm” thing.

I hadn’t noticed the “increased RPM” issue like the others have.

I’ve seen, on models other than the Aveo, problems with low idle speed, usually on 6th generation Honda Civics and CR-Vs from the same era. When it happens on my car, I get out a can of carburetor cleaner and spray it in the throttle body with the engine running, and that usually abates the problem. I haven’t bothered to get mine fixed properly because that low idle speed is saving me fuel and it only becomes an issue when the a/c is running, and I am currently without a/c. Besides, my car has achieved “heap” status. However, in your case, I suggest you undo whatever your mechanic did to increase the idle, and have the low idle problem properly diagnosed and fixed. Your Aveo is too young to be treated with stopgap measures and achieve “heap” status.

I guess you’re right, i will get the idle back to it’s original.

Thanks, I’ll try to get to a a/c garage and see if they can find out what’s wrong.