Hello Everyone...

The Air-con on my 1990 740 works fine when the engine runs cold, but jerks when the engine is fully warmed.

1) Initial idle speed when engine is cold WITH air-con on is around 850rpm

2) Idle speed when engine is fully warmed up is around 900rpm

3) idle speed with warmed engine AND air-con switched on jerks to about 600rpm and the car shudders. I've to rev the engine a bit to get it back to abour 800rpm, before it falls back to 600rpm shortly.

I was told the air-con compensation is via a solenoid switch just below the Fuel Injection unit, unlike a vacuum unit on the 240.

Is this the only thing giving the problem or should I check for some other item..?

How do I go about servicing this solenoid if the problem is indeed from there..?

:beer: