BiggWebb

Can anyone tell me exactly where the air fuel mixture adjustment screw is located on my 1983 928 S ? I'd sure appreciate knowing this.
Thank You!
BiggWebb

Steve J.

The air flow sensor for USA engines has an anti-tamper plug for the idle mixture control screw. Legislation in the USA requires that the bore in the air flow sensor housing providing access to the mixture screw be plugged in a manner that a certain minimum time would be required to make the screw accessible. This is intended to prevent tampering or unauthorized changing of the CO level adjustment. Consequently the bore providing access to the mixture control screw has a plug. Should the idle speed/CO level have to be adjusted, the air flow sensor must be removed to remove the plug.

SteveG

BigWebb: No stupid question here.

I tried to attach a pdf but that is not possible. So I will try to describe it which should be taken with 2 grains of salt as I've not seen the 16V engine. Page 24-24 of WSM shows the air flow sensor. It resides under the plenum and atop the throttle housing. On the passenger side front nearest the throttle housing a few inches below the electical pin connection is a flat area with a small circular indentation about 1 cm in diameter. This is the anti-tamper plug SteveJ refers to. HTH.

BiggWebb

Found it! Thing is buried deep atop the engine as you said and is part of an air control valve of some sort. I made a tool (3mm allen wrench and wire coat hanger) and adjusted the air fuel mixture according to the recommendations of other posts.
Thanks for the responses! They were a big help! With tools from Christman and this forum I hope to save some money on the old car this year. $80.00 per hour shop rates at the Porsche dealer have taken the fun out of driving my 928.
Thanks again!