My car is goofy

[urweak]

Well when i turn on the defrost or the A/C my i get surging. I can cost in gear at any speed and i get a surging as if i was giving the car alittle gas then letting off, or putting on the brakes alittle then letting off. Then i noticed sitting still the lights dime, then the idle climbs, then everything is ok and the idle drops, and repeats itself (goes from about 900rpm tp 1100rpm) You can hear a loud clicking sound when this happens when the car is sitting still. Im guessing its something related to the A/C compressor since it doesnt seem to do this in any other settings.

I did have my A/C compressor replaced in december, so i guess im going to take it back to the shop that fixed it and have them fix whatever it is. But any help pin pointing the problem before i call would be alot of help.

[b2089]

Alot of cars do that. The AC strains the engine which compensates by idling up. I'm not sure if it's an AC issue or if you need a tune up. Has been a while since you've had ac or a tune up?

Not that there's much to tune up on modern cars though. Plugs and wires. Maybe an injection cleaning.

[RocketFast321]

he has a point, but your idle seem a little high

[4kQuad]

You most likely have a vac- leak. The computer is in HUNT mode. Meaning it is hunting for a air/fuel mixture that keeps all the O2 and EGR and what not happy. The Vac- is letting in extra air that the computer can not control. So it is hunting for that perfect mixture.

Listen for a whistle sound or a sound like a small hole in a straw. If It was my car, I would buy some carb cleaner and spray little bursts around any vac- hoses, intake man- exhaust man-

I bet you find it seems so have little power like you wound expect at that RPM as well. Again piont to not enough gas getting mixed with the air.

[urweak]

I wasnt even thinking about a vac leak, since it only does it with the AC or defroster on.

[urweak]

well i got too check it out in the day light. When i turn the AC on the pulley on the AC compressor spins for a second, then stops, and then spins back and forth over and over again. The whole time you hear the clicking sound as if the car is trying to engage the AC.

Should the pulley not spin and the belt slip over it when the AC is off.

[b2089]

I still think a 200 rom range is within spec but the AC is supposed to cycle. I don't think you can tell from looking at it though. the belt will always turn the pulley, the clucthes are inside the AC if it's like mine. If the pulley didn't spin the belt would melt off, and it's easier to clutch them than to use an aparatus to remove the belt from the pulley when the AC is off.

Vacume leaks can cause all sorts of funniness.

[urweak]

Originally posted by b2089
I still think a 200 rom range is within spec but the AC is supposed to cycle. I don't think you can tell from looking at it though. the belt will always turn the pulley, the clucthes are inside the AC if it's like mine. If the pulley didn't spin the belt would melt off, and it's easier to clutch them than to use an aparatus to remove the belt from the pulley when the AC is off.

Vacume leaks can cause all sorts of funniness.

my pulley isnt turning, unless i turn on the AC or defroster. and then it spins for a second then stops and then goes agian, as if the clutch is ingaging it then stopping it.

[RocketFast321]

Originally posted by urweak
the AC compressor spins for a second, then stops, and then spins back and forth over and over again. The whole time you hear the clicking sound as if the car is trying to engage the AC.


Only cars i seen do that was my dad's 91 1500, and astro vans. It was normal for them to do that. But my grand am a/c spins all the time.

[b2089]

I'm not following here anymore. The pulley isn't turning? Then what is the belt doing? Is your car not a serpentine design where the belt should always move?

[RocketFast321]

From what he is saying, when he turn the a/c on. The compressor is clickin on and off. Like the compressor turns on, 10sec later it clicks off. Another 10sec clicks back on.

But i confuse when he says
"Should the pulley not spin and the belt slip over it when the AC is off."

[urweak]

The compressor clicks on and off, turns on for only a second then off for a second, then on and so on. The pulley is spining, that was my mistake, it just didnt look like it was spinning at first.

[b2089]

That sounds like normal AC operation to me then. Cars have refrigeration units on them that could freeze a house if left on. That's to cool the superheated air from the greenhouse effect. The AC cycles on for a second or two and is off for 5-10 seconds.

[urweak]

Originally posted by b2089
That sounds like normal AC operation to me then. Cars have refrigeration units on them that could freeze a house if left on. That's to cool the superheated air from the greenhouse effect. The AC cycles on for a second or two and is off for 5-10 seconds.

there is no 5-10 second lapse, its on, then off, then on, then off, there is only a second between the compressor coming on and going off, and this happens over and over agian, how is that normal AC operation?

[urweak]

Originally posted by RocketFast321
he has a point, but your idle seem a little high

I have a 5speed, you have an auto, i bet your car is around 500rpms, mine is 900rpms

[rixGAphx]

No question here.

Take it back to the shop that replaced the compressor.
Regardless of what 'warranty' was on the work, this is the first opportunity you've had to use the AC, and it is faulty.

It might be that he didn't charge the system with enough refrigerant, or the clutch that came with the unit is weak, or that the controls he hooked-up are now incorrect.
Heck, the compressor he bought from somebody might have been the wrong part. Even tho it physically fit to your engine, the internals could be all different.

BTW, whenever you think 'AC-HTR problem', think 'vacuum'.
All the controls at the dash panel connect to a spaghetti-mound of vacuum lines, which serve to open and close little doors in the ductwork along with the coolant-flow valve for the heater.
If those aren't working properly, it could easily be caused by a loose vacuum line.

Finally, the AC clutch is electrically-operated.
It requires about 20 amps of power at 12 volts to make the clutch 'grab'.
If your battery is low on power, if the alternator isn't charging correctly, or if the battery cable connections are loose/corroded, then there might not be enough power for the AC clutch to grab and keep a grip.
So check those connections, and make sure they're tight and shiny brite.

b2089 (WTH kinda screen-name is that??) is right in that the AC compressor is designed to cycle on-off.
Primarily to prevent the evaporator from freezing into a solid block of ice on those hot, muggy days.
But the cycling, in my experience, is more like 90%on-10%off (55 seconds on-5 seconds off out of each minute).
No way you should get on-off....on-off every few seconds in a properly operating system.

Summary:
*Check your battery connections and look for loose vac tubes underhood.
* Take back to repair shop under warranty (regardless what 90-day or such warranty is on paper; ask Judge Judy, you have additional rights under the law).

Good luck.
-Rick

Disclaimer: I am not an e-lawyer :roll2:

[b2089]

This site has an odd and arbitrary set of banned words. My last name is "k i k e r" without the spaces. aparently that is a racial term so my screen name was banned. Who'd have guessed it.

Are you sure about those cycle times? I thought it was the opposite. Anyway, I don't know.

[urweak]

took it to the shop, the AC clutch was slipping so they are going to replace the whole compressor for me free of charge. Thank you rixGAphx.