Car acting funny when A/C is on...

[Slave One]

OK, my A/C currently works marginal at best due to a failing compressor. Still blows cool, good enough in fact until I rebuild the whole system when my stimulus money gets here...

My car runs great, just did a full tune-up and everything, shifts perfectly, and loves it when I get on her.... that is, until I turn on my A/C system. When I do, its a totally different car...

A definite vibration if felt coming from under the hood. Of course, this is due to my failing compressor. As long as I just BARELY cruise along, it seems ok. But if I get on it at all, it falls on its face. Feels like it has no power at all. Transmission also acts funny, the RPMs will go very high before the transmission will RELUCTANTLY shift into the next gear, if at all. Doesn't seem to want to down shift either. All the while, not a single code is set and no SES light...

Turn the A/C off.. and voila, runs perfect again.

Now my question is this...
Is it possible that whenever the compressor is engaged, the vibrations are interpreted by the knock sensor as knock, therefore, pulling timing and causing all the weird problems?

Also, what else changes computer-wise when the A/C system is on?

[Blizzard242]

Re: Car acting funny when A/C is on...

It's more work on the engine when that ac clutch kicks in, especially if it's going bad.

[cam98aro]

Re: Car acting funny when A/C is on...

It's more work on the engine when that ac clutch kicks in, especially if it's going bad.

bingo

ac compressors take a bunch of HP to run

not to mention the added strain on your alternator running the blower motor, etc

[kristen]

Re: Car acting funny when A/C is on...

if the comp. is going. you might as well just change it to see what it does for you

[Blizzard242]

Re: Car acting funny when A/C is on...

I save gas mileage by using my T-tops :) My girlfriend hates it. Wtf? She's annoying at best when it comes to cars anything.

[Slave One]

Re: Car acting funny when A/C is on...

Thanks guys!

Ohh, i will definetly be changing it very soon.

But is it possible though, for the vibrations to be mistaken for knock? I mean, I know the compressor draws alot of HP to run, but enough to actually affect the shifting of my transmission? The engine is rotating and seems like it wants to go but is being held back, like timing is being drastically pulled...

[cam98aro]

Re: Car acting funny when A/C is on...

i highly highly highly doubt it

[Blizzard242]

Re: Car acting funny when A/C is on...

It's your compressor, it'll make the car slower and you hear the rpms and think it should be shifting.. Somethin to that effect. My car is pretty different when I have the AC on and I try to really get on her.

[cam98aro]

Re: Car acting funny when A/C is on...

It's your compressor, it'll make the car slower and you hear the rpms and think it should be shifting.. Somethin to that effect. My car is pretty different when I have the AC on and I try to really get on her.

werd, my car acts like it has a misfire, or the clutch is slipping with the ac on

it feels like it has the same amount of power as a 100hp FWD car, and when letting off of the clutch it feels like it has no torque, and the rpms drop and dont seem to want to pick up

and then sometimes after the clutch is let out, it will pause on acceleration for 1/2 second, then go again

[Blizzard242]

Re: Car acting funny when A/C is on...

werd, my car acts like it has a misfire, or the clutch is slipping with the ac on

it feels like it has the same amount of power as a 100hp FWD car, and when letting off of the clutch it feels like it has no torque, and the rpms drop and dont seem to want to pick up

and then sometimes after the clutch is let out, it will pause on acceleration for 1/2 second, then go again

Your car has issues. Are you talking about a m5 clutch or ac comp clutch?

[cam98aro]

Re: Car acting funny when A/C is on...

the drivetrain clutch

it only does it when the ac is on

[Blizzard242]

Re: Car acting funny when A/C is on...

the drivetrain clutch

it only does it when the ac is on

It sounds like your is having a hell of a time turning the ac compressor, maybe its goin bad if it's acting up that much. Unless manuals do this off the lot eh?

[cam98aro]

Re: Car acting funny when A/C is on...

It sounds like your is having a hell of a time turning the ac compressor, maybe its goin bad if it's acting up that much. Unless manuals do this off the lot eh?

very well may be

the clutch on the compressor feels hard to turn

every once in a while it makes a grinding noise when the clutch is not engaged

i have to spray some wd 40 on it and it wont make the noise till the oil goes away, i did see some metal shavings around there today, so yeah i might have to put the clutch from my old compressor on there.. just not sure how it works with the seals and everything

[Blizzard242]

Re: Car acting funny when A/C is on...

Lol, I tape my gf's mouth shut and she's quiet till she gets it off. But that's only temporary and it's not a real fix to the problem that she never shuts up. But I suppose if it was really bothering either of us we'd fix it correctly eh?

[kristen]

Re: Car acting funny when A/C is on...

I save gas mileage by using my T-tops :) My girlfriend hates it. Wtf? .

hubby doesn't understand the freedom of the t tops, windows down and music blasting. IDIOT:slap: