Poor running 5kt

[Matthew Beaubien]

My '86 5kt seems to run worse by the day.

I've owned the car about a year, and it ran fine when I got it.  It was only making 1.2 bar, but I fixed a few things and got it up to 1.4.

I played with an adjustable bleed and it pulled hard until the fuel cut.  I didn't bother getting rid of the cut so I turned the boost back down to just under the cut.

About 2 months ago, it started running poorly under boost.  I hooked up a DMM to the O2 sensor and it went way lean under boost (even stock levels).  I fixed some vacuum leaks and part throttle drivability improved.  I also changed the fuel filter but it still didn't pull well under boost.

About a week ago, the car developed a bad bucking problem.  On very light throttle application, mainly in 1st and 2nd gear, the car enters a violent bucking phenomena.  I also have to slip the clutch a fair bit on starts to prevent it from stalling.  Acceleration under stock boost levels seems ok, but I haven't really been pushing it.

I have a friend who has the JCW pressure gauges, and I have the Bentley manuals so I should be able to solve the problem.  The problem is that I don't really know where to start.  Can someone lead me through the procedure?

I haven't adjusted the idle mixture yet.  That will be the first thing I do, but I don't think it will cure all of my problems.

Another symptom is long cranking on cold starts.  I don't know if it's related to the other problems, but it's still annoying.

What does it take to put a carburetor on these things? ;-)

Thanks,

Matt Beaubien
'85 5kt  (die CIS, die)
'73 911E
die CIS, die