Yay! Running ! (sort of) 73.5 CIS Tune

[rockreid]

My 73.5 911 CIS Targa (from cardboard boxes) project seems to nearing its conclusion! With the warming weather I re-started my attempts to get this beast running. I replaced the fuel pump, installed an intake fuel filter drained and put new gas in it today. Still, no start. Only a brief start from the CSI and then would die. So I knew I had spark and fuel pressure. However, I checked for injector spray and there was none until I manually pushed up the CIS air plate with my hand and Key On. I had my wife try to start the car while I pushed up on the plate and lo and behold it started. I gingerly found the sweet spot for it to idle by manually moving the plate ever so slightly up and down until it settled in, probably about 3 or 4mm above its resting place.

Last year I had the FD rebuilt thinking that was the problem. I guess my no Run situation was that damn plate all along. Is the solution as simple as dialing in the adjustment screw until I get a good idle? And what would cause that adjustment to go so far out of whack? I never touched that adjustment screw. What weird is the CIS adjustment allen tool I bought from Pelican is far too long and it seems I will have to cut it to size.

[rpc356]

The air flow plate position is adjustable, but not via that hex screw. There is a nut in the center of the plate that can be loosened to center the plate in the bore. And there is a clip underneath the plate that is gently bent to adjust the height. IIRC, the correct height is so that the top of the plate is even with where the bore changes from angled to verticle. The procedure is in the WSM.

[rpc356]

And, yes, you will have to cut the Allen tool down to size. However, don't mess with that adjustment until everything else is sorted. It changes the mixture, and if it was set correctly it's likely ok.

[boyt911sc]

Originally Posted by rpc356

And, yes, you will have to cut the Allen tool down to size. However, don't mess with that adjustment until everything else is sorted. It changes the mixture, and if it was set correctly it's likely ok.

Richard,

Prematurely adjusting or tinkering the fuel mixture setting of CIS before verifying the absence of unmetered air or checking the fuel pressures are some of the most common blunders CIS troubleshooters commit these days. And you have given the OP a well thought and sage advice. Thanks.

Tony