nbmls1ta

I have read a few posts about people lowering the VE Table in the idle cells to get rid of the rich condition at idle with a larger cam. Mainly lowering until the smell gets better, because the overlap of the cam lets unburnt mixture through and confuses the O2 sensors. My question is, won't the PCM try to keep richening it up to 14.7? Right now I have the 2 cells that my idle is in 15 below the ones above and below it and the LTFT's are around 19 but the exhaust still stinks. Is it safe to keep lowering it? How low have some of you gone with cams around 238/242 .598/.604? I just want to make sure it is ok to keep lowering those two cells. For some reason the LTFT's in the cells around the idle cells seem to be being skewed by the adjustments I make to the idle cells. Any help would be greatly appreciated.
Thanks
Matt

Blacker

iTrader: (3)

I lowered mine a little and it helped. Are you having issues with the car idling or is it just a smell issue? Do you still have cats? If not, there will always be a little bit if smell. If you lower the VE too much, you will go lean and thise fumes burn your eyes.

Silverhawk_02TA

You can lower the VE table at idle as much as you want, but the PCM will just keep adding in more fuel to compensate. This is shown by your +19 LTFT's. Just tune your idle cells like you would the rest of the VE table: adjust the VE values until your trims are close to 0. It's just the nature of the beast: a big cam with lots of overlap is going to let unburned fuel out at idle.