CIS problem

[mas88s]

I have been chasing this problem for a while and I need a few suggestions as to how to proceed.
1986 930 K27, Kokeln intercooler rebuilt 8000 miles ago approx 10 years. 58,000mi
Car starts , after about 7-8 seconds goes super lean and stalls unless I baby sit.
After about 3-4 minutes afr's come down and it runs good. Fully warmed up.
Now here is a clue...If I turn the car off and immediately start it, it does the exact same thing, almost to the second. at warm temps.
Things I've done are pressure checks: system, cold and warm...all fine.
Rebuild fuel head....there were pin holes in the main diaphragm ( thought for sure that would help, but it didn't)
Brian rebuilt the WUR
Thought it was a sluggish fuel pump....replaced front and rear.
Also note that it really sucks down the fuel...10mpg's
I was thinking a faulty CSV ? Is that possible?
It doesn't have enough fuel at first 3=4 minutes and then it guzzels it down.
AFR's at warm idle 13.8-14
Possibly 2 problems??
Any thoughts....
Mark

[RarlyL8]

Is your Lambda system intact?

[mas88s]

Hi Brian...Thanks for a response
Good question.
I know the o2 sensor is connected and I know the frequency valve is buzzing and that's about it.
I guess I'll search for a thread....

[RarlyL8]

Yes make sure that is functioning properly first as they fail regularly with age.
If you didn't have Lambda I would suspect the fuel distributor.

[T77911S]

who rebuilt the FD?
can you post CP's

have someone start it.
verify FV keeps working through warm up.
if you can, monitor FV duty cycle when starting.
more that Is related to the FV:
O2 relay. the FV gets its power from here. could be a cause if there is a problem above.
computer issue making the FV lean mixture.

temp sensor?

try disconnecting the O2 sensor and put it in open loop.

[mas88s]

I rebuilt the FD.
Watched the videos, read the directions and took my time.
Just the O rings and diaphragm. Note the diaphragm had multiple pin holes in it.
I put it in open loop (disconnect the O2 sensor) and readjusted the ARF's and idle.
Car runs fantastic......spirited 20 min ride yesterday.
Better than it has in many months. Very smooth and the AFR's all behaved through the power curve.
Should I go after whatever is making the frequency valve go coo-coo or forget about it?
O2 relay/temp sensor.
From what I've read Lambda is just a emissions add on and I am exempt here in Pa.
Also, Thank you Brian and T77 for pointing me in the right direction. I have been chasing this problem for a long time and I think ......You know
Mark

[T77911S]

that's up to you if it runs great like it is.
lots of people run with the O2 not connected.