[boyt911sc]

Originally Posted by Mac-Porsche

It is a 090 WUR. The lower CCP/WCP was actually by design. I rebuilt the engine last summer with 97mm (3.1L), 10:1 CR P&C's. This hard start and sluggish cold acceleration has existed since the rebuild. I originally thought it maybe needed more fuel due to the higher compression, so I had the WUR rebuilt to run at lower CCP/WCP's. Hence the lower values.

During that rebuild, I replaced all vacuum lines, injector sleeves, o-rings (inner and outers), intake boot, and the airbox was replaced with new one (old one had crack on underside). Installed a pop off valve, double-triple checked for air leaks from the glue holding it in.

Given this problem existed since the rebuild, I still thought it could be a vacuum leak. So I ran all the leak tests I could in my garage last summer - propane, reverse vacuum and soapy water, cigar smoke, etc. Couldn't locate anything. Brought the car to a Porsche-specific mechanic who ran a smoke test, also couldn't find any leaks.

Still not ruling out leaks though, as it does run lean when cold (in 15's per afr meter on dash).

Couple days ago I discovered something possibly worth mentioning... When I start the car cold, it cranks and cranks, put-puts slowly to life. As soon as the car is running stable (i.e. ~10 seconds after starting), I immediately turn it off. No time for WUR to lean out or engine to warm up. Then when I restart the car, it fires up immediately.

It's almost as if the fuel lines need to be primed first. Don't think it's the CSV, because 5-10 seconds of running shouldn't warm up engine enough to disable CSV in the second start (or am I wrong about that?). Checked residual pressures few days ago, they're within spec.

Mac,

I often noticed people not properly doing the pressure tests to locate unmetered air sources. Would you share with us how you did the smoke tests for your motor? How did you isolate the air box from atmospheric condition. Thanks.

Tony