Excessive power loss with AC

[I-S]

It used to be that turning the AC on in my car had a little impact on performance, but not huge.

Now, however, if I turn the AC on at idle the engine dips to 500rpm and nearly stalls, and is generally unable to maintain 750rpm at all. Trying to accelerate the car has absolutely no power whatsoever (yeah, yeah you VR4 owners, I'm talking about compared to normal, don't say the GLS has none anyway!).

Both of these symptoms seem to have existed since I had the battery changed in november, but I've not had call to use the AC since then. The car was generally having low-idle speed problems when the old battery was knackered, but it's fine now other than when the AC is running.

Also, when I turned the AC on with the bonnet up the other day, both radiator fans immediately kicked in on high power.

Is there something wrong?

[Paul Beazer]

Now, however, if I turn the AC on at idle the engine dips to 500rpm and nearly stalls, and is generally unable to maintain 750rpm at all.


Also, when I turned the AC on with the bonnet up the other day, both radiator fans immediately kicked in on high power.

Is there something wrong?

Hi Isaac,

If i may offer a suggestion, when you disconnect the battery and reconnect it it resets the ECU, so it has to "re-learn" what its supposed to do! I had similar issues when I disconnected the battery on my v6 sport a couple of months ago. A couple of hundred miles later with varied driving its back to normal.
I think probably why yours isnt running too well with the AC on is because the ECU hasnt "experienced" the AC since re-connection, so it doesnt know to compensate for the extra load on the engine from the compressor.
You could try disconnecting the battery then re-connecting it. When you do, drive normally and go for a burn with and without the AC on and it should re-learn what to do! After a couple of hundred miles it should be ok.
If you havent used the AC since nov then you might want to get it topped up / serviced. If the AC is not used regularly (once a week or so) the oil the coolants mixed with can settle and lead to leakage as the oil isnt keeping the gas tight seal. I got mine fully serviced etc for £75 locally (not from the mitsi garage, they wanted £110!)
With regard to both fans running, they'reprobably trying to cool down the AC gas after compression. Try turning the temp up ie warmer and they should stop running, mine does this when you set it to maximum coldness, when you turn it up they stop. If they dont calm down it could be the gas needs topping up as the system has to work harder to cool the remaining gas.

Paul