G Man

Is there a way to increase my cold idle speed without increasing the warm idle speed. The idle is pretty much the same cold or hot so I think something may be out of adjustment, but I could not find any info on my CD / manual. Does the temp sensor control the idle speed when cold? This is on my 84' L-Jet. Thanks.

ZEUS+

Check the auxillary air regulator. pg 24-18 in WSM

BC

IIRC, there is a largish flathead that points up at an angle at the front or back (front I think) of the TB. That will raise or lower the idle.

That could be it. Don't shoot me if the images in my brain are from one of the other 4 928s I have owned. But I remember this from the 81 (which is LJet)

karl ruiter

Short answer is no, there is no seprate adjustment, normally. But then again, the goal of the system is the have your idle speed be the same when cold as hot, so perhaps there is no problem. Or perhaps your aux air valve is stuck open or closed. On my Ljet car I was never unhappy with how it worked, while on my CIS car I had a problem in which the cold idle was too high. I fixed this by putting a restrictor in line with the aux air valve, and dialing it in unitl I was happy with both cold and hot idle speeds. So, it is possible to adjust to cold idle down, but I don't know about up. I'm sure it could be done if it was possible to take the aux air valve apart, but I don't think it can be taken apart. How about using the air conditioning valve to boost cold idle up? As a first pass, you could just run it off a switch.