Surging idle when ac is on?

[THUCK]

Motor surges from about 600 to 1100 when ac is on. I got a 89 535i. When ac is off no problems. It just started after I installed the eat chip maybe a coincedence. Any ideas?

[JonE]

Try contacting Mark D to see if he might know if there is a connection between the chip and the AC. If the rev variability coincides with the compressor kicking in and out, your freon/refridgerant might be getting low. Just a guess, though.

[Bill R.]

the compressor due to low refrigerant charge. When the compressor normally comes on the idle speed control automatically raises the speed slightly to compensate for the load of the compressor, if your low on freon then the compressor cycles on and off rapidly enough that the computer has a harder time compensating an you end up with this rpm fluctuation up and down...










Motor surges from about 600 to 1100 when ac is on. I got a 89 535i. When ac is off no problems. It just started after I installed the eat chip maybe a coincedence. Any ideas?

[THUCK]

Now its surging without the ac untill the motor gets warm?