Warm start up..15.94 A/F & stalling?

[clemsgn]

This is a T-R 231 w/FAST which runs fairly well, but has a few issues. One is, when it's warm if it stalls at an intersection (AE problem) or I shut it off and immediately start back up, I notice the A/F is at 15.94 for a while (if it doesn't stall again for being too lean) until I rev it up a bit (may stall ?). (I'm restarting without turning the key off to avoid reconnecting the ECM so I can see the dashboard as soon as it starts, but I've tried turning the key off 1st also) Sometimes if it stays running and I let it idle for 20 - 30 seconds, it may run ok but then stall again when put in gear. Once I drive around for a while, it seems ok, but if I'm not carefull taking off from a stop, it may stall again. It seems if I give it a very short but quick amount of throttle from a stop , it may stall and it may not. I've messed with the AE tables for hours to no avail ! Sometimes it gets close, but never right.
Another issue is cold startup. It starts up and then stalls. This is normally afterstart fueling. How much afterstart enrichment % is typical upon startup at 60 deg air temp ? I believe mine is around 25% and then decays to 0 in about 1 minute. Obviously it's lower at higher water temps and decays quicker, but why the stall at first start ? I thought it may be the fact I have 2 external fuel pumps without a check valve and fuel pressure drops down quickly as soon as the pump stops. I've even changed the fuel pump prime to hold at 20 seconds, but it still happens.
It has a 70mm TB, 72 lb injectors, 3-bar MAP, 212 roller, stealth 72 turbo, WB is mounted 10-12" from turbo in 3" TH Downpipe, 3500 stall Art Carr non lockup.
Anyone have any ideas I can try ? Norbs ? I can send you my configuration or a log if needed

 

[norbs]

Sounds like a common problem i ran into with my car. Your on the right track its afterstart enrichment. I usually make the afterstart decay out within 30 secs hot or cold. The rest of the enrichment will come from the warm up enrichment graph. My cold afterstart is about 35% and warmup fuel is about 25% at the same temp. Send the logs and gct when cold and warm. Send to norbz@sympatico.ca

Just give me a few hours, welding up exh leaks!

 

[clemsgn]

Thanks Norbs, but I read a post (FAST WBO2 tip Aug 19) that said he sprayed the WB connector with WD40 and his car ran great. Well I inspected my connector and it looked perfect with no corrosion, dirt or moisture, but it was under the tube coming out of the A/C evaporator. I re-routed it away just in case condensation might drip on it, as I've had the A/C on recently. I didn't like the thought of using WD40 on an electrical connection as critical as the WB, but I did have a can of good quality electrical contact cleaner that I tried. I sprayed it and plugged it in & out a few times to get good contact. Upon 1st startup, it stayed running and A/F was better in the 12.5 - 13.5 area when cold. It also seemed to run very smooth. I keep the idle around 870 and is ok most of the time, but on some days it was a bit shakey especially just after warm startup. I lowered the idle to 800 without a problem. Now I can restart warm and it runs much better than ever, without the 15.94 A/F it had before ! It also didn't stall when put in gear...cold or hot ! I had no idea how critical this connector is ?? The thing is it looked very clean ? It must need to be laboratory clean ! I wonder how many other sensor connectors need cleaning ? ?
The only thing I have to work on is the AE but that's just with a very short & quick amount of throttle for it to stall. Right now I can't get files off of my laptop...no floppy drive and not online. I will get a USB jump drive soon and if I'm still having a problem, I'll send you a log and gct. Thanks again Norbs Comments ?

 

[norbs]

The O2 connecter is very poor i agree, i have been having some issues with it also. Glad you found the problem though. Oh BTW i put a stageright transbrake in, so no more 1.7 60s i hope!

 

[clemsgn]

Yes, I now believe everyone that uses the WB should spray and work the plug in & out a couple of times to ensure the connection is right. I've spent waaaay too much time chasing all sorts of problems, and now most are gone by this method ! Now if I can only get my AE perfect, I'll be OK. Last year at the track my T would run down to 9:1 ratio by the end of the run (started around 11.5:1) I wonder if this was the problem ? I should be able to knock a 1/2 second off my times now !!??

Norbs let me know how that stage right works out ? I never liked the idea of shifting out of 1st to release the brake especially with the stock shifter. Do you have an aftermarket shifter ? If so, what type ? (I used to get 1.5's 60ft. with my GN off the foot brake, but I haven't done that well with my "T")

Thanks again and get those connectors clean !!