Hello...does anyone know what causes the idle to get bumped up when the ac is turned on? Is it a relay somewhere?  Its fuel injected. car runs and idles great..but when I turn on the ac the idle drops dramatically when the engine should actually increase the idle to compensate for the increased drag. Thanks

Edited January 16, 20215 yr by primosoup

SPFI or carby fed EA82? 

Carby has a little vacuum diaphragm that pulls on the throttle to increase revs. 

I’m not familiar enough with SPFI to tell you what does the idle up. 

 MPFI uses a little solenoid on the side of the throttle body, but I think this only applies for the turbo EA82 and NA XT4  models in the USDM. We got the NA MPFI as an option in our touring wagons. 

Cheers 

Bennie