Cis Help??

[1980SCINVA]

I have a 1980 911 sc coupe I just had my motor fully rebuilt and my cis has sat for at least 8 weeks...I live in Va and had the work done in n.c. so my mechanic in va gets the motor in and says he sets the idle to factory specs and the car will cut off sometimes and idles rough....where should I start?

[boyt911sc]

1980SC,

You need to have a basic understanding of the CIS principle. For reference, read Jim Williams' article about CIS and some other books dealing in details how CIS components work. Familairity to CIS compoments like WUR, AAR, CSV, TTS. etc. is important.

In troubleshooting CIS problem, the first thing I do is determine the system and control fuel pressure using a fuel injection pressure gauge. This fuel pressure kit is mandatory for CIS trouble shooting in general. I am assuming you want to DIY or have your mechanic fix it.

And lastly, do a search in the tech forum under WUR, AAR, etc. and a great deal of discussions have been brought up in the past. A lot of people in this board will try to help fellow members find an answer to their questions. Good luck.

Tony

[HarryD]

CIS is very sensitive to things like vacuum laeks, dirty fuel, poor timing, bad plugs, faulkty CID, bad points etc. Before you start fiddling with the CIS, check the rest of the ignition/fuel systems to be sure they are not contributing to your problem.

Onvce you ahve convinced yourself every else is top notch, then go after the CIS. This TROUBLESHOOTING CHART can help you make some progress.