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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,289
If your CIS air flow meter housing has the 3mm idle CO adjustment post in between the fuel head and the air flow sensor plate try turning the 3mm allen head adjustment screw clockwise a tiny bit.
You have to press the allen wrench down inside the post and gently turn it until it drops down a little farther and engages the allen head screw in there.

Turn it clockwise or to the right for richer and to the left for leaner.
Tiny adjustments have a large effect at idle speed and a very small but still noticeable effect at higher rpms.

When I had an '87 911 turbo with a CIS Flowtech 007 fuel head, 964 cams, and B&B headers it idled smoothest when idle AFR was between 12.8:1 and 13.2:1 after the motor was fully warmed up or after around 20 minutes of driving.
12.8:1 seemed smoothest at idle and steady 65mph cruise on flat Florida interstate was usually around 15:1.
I never had an exhaust temp gauge but did have a VDO cylinder head temp gauge with it's thermocoupler sensor on the #5 spark plug.
The heads warm up fast on these air cooled engines.
Old 05-03-2018, 09:08 AM
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