Idle speed adjustment, Carrera 3.2
 

Can Idle speed be correctly adjusted without emission measurement equipment in Carrera 3.2 (1984) with DME?

The authorized Porsche service told me that it cannot be done without simultaneous emission(CO?)-measuments.

I know that there is a small screw on the idle control valve just above the fan and turning that would affect the idle speed but will the emissions and mixture (lean/rich) be also affected?

What would be the CORRECT procedure?

The car is an european model without emission control equipment.

Thanks,
TommySmileWavy

ignore me...;)

Tommy,

No I think you need equipment to be accurate with fuel mixture. The small screw you're referring to is the idle speed screw. The air/fuel mixture screw on a US version of the 3.2 is located on the Air Flow Meter. I'm not sure about the the Euro version though.

Tommy,

The official Porsche procedure to set the idle does state that the idle CO level must be set first.

In reality, I do not find that necessary unless your idle mixture is really wacky.

The way to set the idle is to get the engine to operating temp and then disable the idle stabilizer valve. There is a female plug connector on the left side of the engine compartment (near the relay panel). You jumper the B and C sockets to disable the ISV. You can now set the idle using the idle adjustment screw located above the ISV (it might be covered by a plastic cap). My Multimeter has a "tach" function, so I use that to set the idle since it is sitting in the engine compartment and it's more accurate than the dashboard tach.

Dan is correct. The idle mixture is adjusted seperately and is set using the adjustment screw located on the underside of the AFM. This mixture adjustment screw may be covered by a metal cap if it has never been adjusted. When I set my idle mixture I use the Gunson CO Analyizer which gives a digital read-out of the idle CO level.

Bruce

Thanks for everybody. I also did not belive that I could be so complicated.

/Tommy

Tommy,

To simplify the proceedure, just ignore the previous instructions and set the idle screw the way you want. In all the years I have had my 86 Carrera I never needed or used a tach to set my idle, just did it...forget all that BS.

Cheers,

Joe

Joe