Airflow sensor adjustment, L-jet troubleshooting Options

[Anton]

My 1.8 engine was running badly at idle and sounded harsh on acceleration. CO screw and dwell/ignition tune-up did not solve the problem. I thought it was time for another valve job until a 914 buddy of mine, Richard, adviced me to check on the airflow sensor. (IMG:style_emoticons/default/ohmy.gif)

After removing mucho messy glue on the cover (thanks, PO) and opening of the sensor, I found that the mixture was way too lean. There was a marking of the old position that was richer, but only after adjusting beyond this point, at a total of 8 (!) teeth on the wheel, idle became regular. What it did to acceleration and low rev. driving was even more remarkable... Is this what a 914 can do...? (IMG:style_emoticons/default/laugh.gif)

It all became evident after a period of driving with backfire due to wrong dwell/timing. Some of you will now probably say "evidently". Also I have heard of this problem before, "just readjust a couple of teeth on the wheel", but a total of 8 teeth! (IMG:style_emoticons/default/blink.gif)

Anybody care to comment on this? Is this usual for an L-jet?

BTW, I have not yet checked the current CO reading.

[Qarl]

There is an adjustment screw on top (accessible without opening the cover). It's in that deep little hole.

There is also a way to change the characteristics of the AFM by messing with the cog and the spring inside. This essentially allows the flap inside to open more freely, tricking your FI computer to think that there is more air flowing in and this richening the mixture... (or something like that).

You really just need to mess with the outside screw first and use a CO meter to get your A/F ratio correct. This can cure some backfiring problems on deceleration.

Also.... DEFINITELY check for cracks in your tubes... I think you can spray some fluid (someone help me out) and "check for leaks". Have an extinguisher handy.