Air Con Problem

[08Elf]

When I have the Air Con turned on at idle sitting doing nothing it's fine, although it does idle fairly low.

When driving the car with the air con on it's fine, the problem starts when I slow down to stop.

If the Air Con is on and I down shift basically when I put the clutch in when the car is going 50km or less the car dies. So even if still moving.

I think I need to adjust the idle up about 500rpm or so it idles normally at about 900rpm and with air con on it will die down to about 500rpm (currently it idles at the idle line indicated on the standard RPM indicator)

Do people think it's the idle being to low and that adjusting the idle will fix the problem?

If it is the idle how do I adjust it to fix this problem?

Thanks in advance

[Cubes]

Check the AAC valve's solanoid is plugged in. If not it looks like the solanoid is buggered.

or.. Maybe the AAC valve is too gummed up for it to move?

Acc valve is the little device hanging off the back of the plenum near the firewall.

Has a hose and wire going to it with a little motor looking thing (the solanoid)

[Ant]

The base idle is supposed to increase when the engine is cold and/or the AC is on, this is controlled by the Idle Air Control valve, sometimes also called the AAC valve.

This valve can get gummed up and/or fail causing the problems you are having. See here for details on exactly what it is and how to fix:

http://www.gt-skyline.net/ (link on the RHS to AAC valve stuff)

[08Elf]

Need some info please,

After reading the page on the above link I checked all the connections and made sure it was all clean, but when I first checked it wasn't connected firmly, like it just pulled straight of and I didn't need to unclip it at all.

Would the fact that it may not have been connected properly cause the problem?

[Ant]

Quite possibly, if the connector wasn't connected properly then the ECU wouldn't be able to control the valve.

Has the problem gone away?

[08Elf]

Well hard to say I drove it today and the revs at idle seem to have increased, nothing differenet about the weather today either than other mornings.

But they seemed to die down after the car had warmed up.

I put the Air Con on and it didn't do what it was doing before but i'll have to wait until the internal sensor reads higher than 18 degress.

But looks like problem solved.

I'll be going on a cruise here in Canberra on the weekend hopefully the weather is warm so I can test it nice and properly.

Cheers for all the help

[Ant]

Good to hear it sounds like it is working.

Yep, the idle will die down when the engine is warm, the ECU dynamically adjusts how far open the AAC valve is depending on temperature etc.

If you switch the AC on at idle, the idle rpm should go up to 800 - 1100 rpm.