87__TA

Sort of new to LS builds - I have tuned 1 for friends build which went great.. Just finished building my own and having a start up issue I can not seem to figure out. Using 411 PCM.. Have car running and have been working the VE table (Not using MAF).. Things going well there but having a cold and warm start issue -- But worse warm it seems..
Car fires instantly then stalls.. Over and over.. I can catch it with throttle but acts like it has no fuel for first few seconds then it catches and runs good.. Not flooding at all, just seems like way to little fuel or hardly none as soon as it fires. Everytime you try to start it continues to fire instantly then stall.

I do not assume it is not crank VE as it fires instantly, I have played some with start up enrichment but no help.. I saw after start prime delay which made sense - Thinking it would continue prime pulses longer, so I moved from 0 to 2 with no change what so ever..

Any thought on this?
Thank You for any help.

Not sure it matters but 408, PRC 247 HEADS, 224/228 baby cam for now.. Single 88mm coming soon

jimmyblue

iTrader: (11)

What is your startup IAT reading, the commanded AFR
and the delivered spark timing during the initial bad and
the subsequent "better" running?

Startup enrichment may be too much, not too little -
and if you are cammed, look to the open loop EQ table
and how over-enriched it may be making cold starts
due to idling at a higher MAP than factory and pushing
enrichment where it's not needed (then compounded
by startup modes).

NicD

iTrader: (7)

What throttle body and intake? Post the tune, at least there is something to go off of with that instead of guessing.

87__TA

I will try to get that info - BUt not sure if what I can scan while trying to start.. But once started will run fine after a few seconds.. The only reason I say I thought to lean is if I clear flood and hold throttle open it will not fire at all.. If I hold slightly it fires more violent of course but stalls instantly.. Literally goes to 1300 soon as it catches a fire and instantly dies. Like you just squirted just a shot of either in a dry motor.


Stock LS2 intake currenlty and using a POS ebay throttle body due to the intake - I have a PTM 102 that was on my previous 23 degree chevy that I will use.. Using this loaner for time being till I get a VR.. however the throttle body did work fine on car its from.. Which is where the loaner small cam came from... IAC does seem to stick closed at times.. ut as said even cracking thottle will not let it run.