AC and almost Stall

[volavet]

When I turn the AC off, the rpms dip very low and it sounds like the vette wants to stall, but then catches itself. Does this indicate the alternator is on its way out? Any advice would be appreciated.

Thanks

 

[Vettelt193]

how many miles do you have? it might be a vac. leak, or other minor maintenance item, sorta depends on miles though.

 

[volavet]

It has 33k miles and just had $3k in work done, water pump, opti, all fluids, etc. so the car was gone over from head to toe. All the hoses were checked so I am pretty sure it is not a vaccum leak, but anything is possible.

 

[Vettelt193]

I really doubt it is the alternator because you are turning the AC off, not on, when the problems happen ( but I could be wrong.)

with such low miles, it seems very strange... does the idle surge at all when the A/C compressor cycles normally? (say, you set the AC on 75 degrees, when it hits 75 the compressor will start to cycle on and off to maintain the temp).

 

[volavet]

No, and the whole thing may be normal as I dont use AC that often, but it seemed odd that it would dip so low and or almost stall as a result of the AC being turned off. I understand it needs to catch up to having less drag on the engine once the AC is off, but I thought it would not go to the point of almost stalling. Thanks for the replies.

 

[Tuna]

When was the last time the throttle body was cleaned?
The Idle Air Circuit might be a little sooted up.

 

[Vettelt193]

When was the last time the throttle body was cleaned?
The Idle Air Circuit might be a little sooted up.

I was thinking that, but only with only 33k miles do you think it can get that gunked up? I am curious to know how bad it can be with low miles and 10 or so years.


Volavet: do you know the story behind your car? did it sit for a while before you bought it? when I bought mine I found out (after I bought it) that it sat for about a year. I had a handful of problems related to non-use

 

[volavet]

Its been sittting, but I have started it off and on and have owned it for 5 + years. I just had $3k put into it for all fluids, opti, water pump, etc., so it has been gone over with a fine tooth comb. However, I have this annoying whistle sound (as you can see in my other post) and I now noticed the AC issue, which may be normal, I just expected it to give power when the RPMs dropped from turning the AC off. It may be the idle air control. I know the intake is not gummed up, I had it cleaned only 5,000 miles or so ago.

 

[froggy47]

Idle should go up about 200 rpm when ac is on. Any codes?

 

[volavet]

No codes, just drops very low and almost stalls, but catches itself at the last minute. Other than the AC to no AC transition, it runs perfect. I dont know if Im being paranoid, or if its abnormal for it to sound like its going to conk out when I turn the AC off.

 

[froggy47]

No it's not normal, but I'm at a loss what to suggest, maybe someone else will pitch in.

Try www.corvettemechanic.com