Engine cut out with Aircon switched on.

[Robatron]

Hi guys,

Im not entirely sure where the best place to post this is as it kinda falls under aircon and engine & turbo.

Anyhow the problem I have is this. When I have the aircon on and gently accelerate, and I do mean gentle, I get a very aggresive hesitation. I would describe it exactly how other people describe boost leaks!

It happened a few weeks ago and I figured I had acquired a small boost leak somewhere, but it dawned on me this morning when I had the aircon on to help clear the screen that this occurs everytime I have the aircon on.

Is this a problem with the aircon interferring with something, or is it the fact that the aircon is highlighting the fact I have a boost leak somewhere?

Any help is much appreciated!

[Crawford_S2]

My aircon seams to drain a lot of power too, so i don't use it! Makes coming up to junctions and dipping the clutch a bit of a lottery too

[cuz-gs]

Aircon

Hi There

I had a similar problem in the summer in the RS2. When I turned my aircon on it stalled the car and felt generally inadequate. Usually aircon related problems can mean £££, so I was a bit scared! I went to an Aircon specialist who diagnosed the problem as a sticky compressor, which he rectified.

The main problem seems to be lack of use from what he was saying. "Use it every couple of weeks just to keep the oil moving in the compressor" was his advice. I was happy, a less honest gentleman could have taken me for a new compressor!

Dunno if this helps, but some more experienced guys maybe able to diagnose if its a boost leak related problem.

Simon

[Robatron]

Thanks guys!

Its doesnt stall as such, its just very vicious hesitation or stutter. You can almost feel the revs drop to 0 and fly back up to where they were in a fraction of a second.

It doesnt sound very boost leak like, but I cannot see why the aircon would induce it.

I hope that someone somewhere has had this problem and its not as expensive as the normal aircon problems.

[s2driveruk]

yep i know what you mean on this and mine does it from time to time too but less so when i use it regularly so might be worth getting someone to check the compressor over, though i think Dan had his system replaced and regassed more than any other member on here so hopefully nothing too serious.

Still need to get mine off the car and solve the leak/squeal I have which i think is down to the clutch going on the compressor though could just be the belt being old...

[dan_b]

yep i know what you mean on this and mine does it from time to time too but less so when i use it regularly so might be worth getting someone to check the compressor over, though i think Dan had his system replaced and regassed more than any other member on here so hopefully nothing too serious.

Ain't that the truth! That's compressor number 3 on there during the time I owned it, and I never switched it off when I was using the car.

Rob didn't you have all the belts replaced just recently, maybe one of them isn't at the right tension or something?

[blown_vr6]

Clean and relube your ISV guys - they get gummed up and cant react quickly enough under heavy load - ie Air Con on.

Pete.

[Robatron]

I wouldnt have thought the ISV could produce such a vicious cut out to be honest, but hey, anything is worth a try Pete.

Dan/David.

I hope its not a case for a new AC compressor!!

Yes I did have the belts changed so perhaps that is a possibility, but I am also guilty of not using the A/C in this particular weather.

[Markarina]

I had problems with Aircon in the past which turned out to be corroded connectors on the condenser where the various pressure sensors connect. This had caused the Aircon to cut in and out the whole time, similar to your problem but different I suspect.

[Robatron]

So it looks like I need the compressor checked over then. I pray it isnt that

I would love to know of anyone who has discovered a boost leak through the aircon causing this problem, it seems very unlikely though doesnt it?

I havent discovered it doing this when I give the car some welly, I shall have to give it a try. But I certainly know that on gentle throttle it occurs and its vicious!

[dan_b]

Rob - is the car particularly damp at the moment, ie. just wonder if it's electrical - distributor/ HT leads? Loose sparkie?

[dan_b]

Rob - just a thought, I wonder if it's the clutch on the compressor rather than the compressor itself? If the clutch is somehow not clutching properly I'm sure that could cause the issues you're experiencing?

[Robatron]

Thats not a bad idea Dan!

I had the car running on tickover today with the aircon on and I still got this very quick cut out. It wasnt as noticeable given the revs but it proves to me that its definatly not boost related as I first thought due the fact that the engine wasnt under load at all.

I will get this assessed as I have noticed no drop in revs when I first engage the aircon, whereas on my 8v coupe you can detect immediatly when the aircon has been switched on.

[dan_b]

You should feel/hear a small change in engine note when you engage a/c independent of the main rad coming on. Is the main rad coming on?

[Robatron]

I had the chance to check this morning. Yes I can feel the aircon cycling in and out and yes the main rad fan does come on.

Now, the other day I cant say as I heard / felt the engine note change as the aircon went on, so perhaps a sticking compressor clutch is the offending part?