CIS not starting

[MD540iT]

Hey all, heard this was the place for CIS help.
So,to be transparent, this is on a 931(thats the 930 with the engine in the front! very rare!)

Ive been working on the car/engine for a long time, short of pulling the engine and rebuilding it, i've gone through pretty much all of it, and either fixed replaced, rebuild or resealed almost everything.

I have a CIS pressure gauge, and Wide band 02, and a Dual adjustable WUR.
I had issues running rich, then lean, turned out to be a bad 02 sensor, so I replaced it and took it on a test drive. seemed to fix the issue.
I did a couple full boost (12psi for now) runs and I blew off a 19mm intake hose, but just put it back and drove home, with out issue.

couple days later I go to start and, no start.

at the point I have been playing with it trying to figure out what the heck is wrong, and am not getting any direction.

So at one point I just continually cranked for almost 10 seconds, and held the throttle WOT (out of frustration) and it started to "run with the starter" then it started for a few seconds and died.

few more tries of that and a certain point without holding the throttle WOT or continuously cranking, it would start and die, almost like it was running on just the Cold start injector, So i unplugged the Cold start, and the engine stop starting for moment.

I tried adjusting the mixture screw much richer and leaner in 1/4 turn increments, which didnt seem to make much improvement.

I swapped my adjustable WUR for a stock one. I have a switch to manually turn on the Fuel pump.

I was getting near 95psi Cold System pressure and 22psi Cold CONTROL

I can hear the injectors spraying when pushing on the Meter plate

Ive got spark, got fuel pressure. I can't find any intake leaks.


So whats confusing,is that it ran just fine, before, and It will start (barely, sometimes)
I can't find anything wrong (yet). Im not sure what could have changed. The other things I could check wouldn't tell me what much I doubt (such pulling the injectors and checking for volume, as I doubt they would go bad sitting for 2 days (and I cleaned and flushed them)

I even got a ethanol tester, and the Gas is only 5% ethanol, so thats not it.

What if the aux air regulator was stuck closed? or the decel valve failed?


thanks.

[T77911S]

931?
i think we need to see pics.
cant imagine that.


is the spark strong enough. possible bad coil giving weak spark.
do you have power to the CD unit with key on. (you may be getting power in start only)
AAR closed, no. it wont stop it from starting. neither would the DV.
CSV could make it not start/hard to start. you can work around that by pressing on the mixture adjuster (meter plate) to dump some fuel in it. try it while cranking.

how do you know there are no air leaks. how about Orings on IC.

[MD540iT]

Originally Posted by T77911S

931?
i think we need to see pics.
cant imagine that.


is the spark strong enough. possible bad coil giving weak spark.
do you have power to the CD unit with key on. (you may be getting power in start only)
AAR closed, no. it wont stop it from starting. neither would the DV.
CSV could make it not start/hard to start. you can work around that by pressing on the mixture adjuster (meter plate) to dump some fuel in it. try it while cranking.

how do you know there are no air leaks. how about Orings on IC.

I pulled the wire off the coil and watched it arc.

Well, it did run for a few seconds after I let go of the key, so i'd think thats a yes??

I have replaced most of the boots/elbow with new rubber of silicone, rebuilt the T-body, new oring on the turbo/intake/outlet can't spot anywhere obvious, or where a big enough leak would stop it from firing.


But what throws me, is why I was able to get it to start (just barely) with WOT and a Loooong crank. Now im starting to think, bent valves, bad rings, slipped timing; but when it did start breifly it seemed fine.

at one point, it almost seemed like it was going to run Yayy....Oh, nope.