pcmhacking.net

So a win and a loss at the same time. still misfiring at operating temp. But i am able to get LTFT data now. I also noticed the spark advance increase up to the 40s. any ideas? Ive attached the log if anyone feels like telling me what they think, would be much appreciated.

Tried to read your log. Can you post the definition file your using.

sorry my bad. I also had a bit of a brain wave overnight about my lifters. New pushrods on the way.

Are you thinking they may be too long?

IMO you have too much timing. 30deg at idle seems a bit too much but I may be wrong. Something is happening when the O2 sensors start working you can see it at 3.26 in the log. When the O2 sensors start working the timing jumps 10 degrees. When tuning you best to turn off the O2 sensors from memory it's done by setting the turn on temp as high as you can in the tune. This prevents it interfering with your changes. Left hand trying to fight the righ. See what happens with them off and post back a new log. Also post your latest BIN file and XDF.

i thought the lifters i put in were oem spec. but they were ls7 lifters. so i think i have too much preload.
to me it sounds like a vacuum leak which is why i was thinking it could be a cracked head or inlet.
Ive got the pushrods out atm, ill run that test in a couple days after i destroy it with pushrods that are too short lol.

Just had a look at std timing table for L67 and it seems they do have heaps of advance in the low rpm area. Try turning off the o2 sensors and see what happens.

LS lifters?

When I built the engine in my VP I used genuine LS lifters and measured the preload with a dial gauge setup and adjustable measuring pushrod. Once I had the exact preload I measured the adjustable pushrod, then I ordered the right length from Crow cams.

Mine ended up being shorter with the new lifters and decked heads and block, LS lifter have about 1mm less preload than the old gen lifters that the V6s came with.

Charlescrown wrote:IMO you have too much timing. 30deg at idle seems a bit too much but I may be wrong. Something is happening when the O2 sensors start working you can see it at 3.26 in the log. When the O2 sensors start working the timing jumps 10 degrees. When tuning you best to turn off the O2 sensors from memory it's done by setting the turn on temp as high as you can in the tune. This prevents it interfering with your changes. Left hand trying to fight the righ. See what happens with them off and post back a new log. Also post your latest BIN file and XDF.

Im not sure how to do that lol. Ive just been logging.

I pulled off the m90 and noticed all coating was coming off the rotors. Quite a bit of it actually. Is it possible that a worn supercharger would cause this condition/misfire?
also did a leak down test, all cylinders are under 5%.