Been out of the game for a few years and I'm a bit stumped as to whats going on

started out with a stock tune, put the car into open loop and did some logging, i copy and pasted 4 tables of VE High and low rpm, and i made a histogram to log afr error on low rpm coastdown and also idle VE

pasted in all the new values, in open loop car runs fine , idles like its supposed to , put it back into closed loop and it idles in the 11s and 10s? WHats going on here, also we are using the wideband to sim narrowband 02 readings



1989 Turbo Trans Am #82, 2007 Cobalt SS G85

like i said on the phone, its best to tune the low and high rpm VE tables only.

leave idle and coastdown tables alone, you're only going to make it worse. there's multipliers that effect them that we cannot see, which is part of the reason you guys are having so much trouble.

just tune low rpm single/double and high rpm, thats it.

leave everything else alone.

Ok, ill return those to normal then. Some other interesting things to note injector duty cycle was at 85% and this is with a VE table thats using a 20% offset, highest value was at 5300 with 114. That concerns me a bit for the future when further fueling is needed. Also we are using a IPW vs Vac table that is set to 1s across the board, good or should stock be used? Also noticed that the map is reading 95-98kpa under WOT, perhaps its only boosted cars that read the full 104? The variance between HPT and the LC1 seems to be very little if at all between wideband readings. At most theres maybe a 2-3 tenth difference, I'll take running high 12s now over running high 17s at full throttle on AFR. Not sure if the narrowband simulation is working or not I have to get the car back into closed loop and check the mv.




Edited 2 time(s). Last edited Monday, July 20, 2009 8:39 AM


1989 Turbo Trans Am #82, 2007 Cobalt SS G85

Matt, like pj said tune the tables individually, also leave DFCO alone completely. Don't disable it and disregard what your 0% throttle gives your for your ve tables. As for the injector compensation, With my boosted set up I was running the lsj injectors at 76% ve offset. If it isn't an aggressive NA build strictly bolt-ons, then I'd just run the stock injectors. the stock injectors will be fine even if you bump the offset to 30%. If you still don't feel comfortable then run larger injectors...Before I swapped to the 42s, on the dyno I saw an hpt idc of 108% nearing rev limiter.

well im sure philbert will have super huge injectors at some point so that will be little issue



1989 Turbo Trans Am #82, 2007 Cobalt SS G85

stockers are going to be maxed out straight away matt, don't bother worrying about AFR too much until you bump them up to LSJ injectors or larger.

def figure that knock issue out tho.. something is def not right there

Agreed, get at least 30lb/hr in there. Ford red tops are cheap and easy to come by on ebay

Hows the narroband sim workin for ya? Are you getting back stoich on the WB in closed loop cruising?