Deenasty

I am in need, and running out of ideas. Do you folks happen to get split BLM's at idle, due to the amount of overlap of the camshaft? I am having this problem and trying to see if its the "false" lean causing this, or if its just my car. Please give me some feedback. Thanks!

blkchevyz

not sure about those cams, but i have decent size fms cam and i had to tune it in open loop to get it to run well.

my blms would be at 128 but my air fuel ratio with a wide band would read 18-19 to 1

slverbullet

what type of TB do you have? also, have you hooked up to a computer and monitored your engine running? if so, is the split blm only at idle or while driving? are the o2 sensors still good? have you swapped them sides to verify that the condition does not follow the plug? do you have any exhaust leaks?

Deenasty

So yours run in open loop only? Hows your gas mileage?

Deenasty

Its a BBK 58mm tb. I already played with the throttle screw, with no luck. I have everything to monitor my vehicle, and it is only occuring at idle. I believe its a false lean condition only on bank 1. The o2's are brand new, and no exhaust leaks are present, because there is no carbon buildup on anything.

calfirebird

My blms were split on mine but it was caused by the MAF sensor. I had a ported and descreened maf and i had to have ed wright fix it with tuning.

slverbullet

how are the IAC passageways on the BBK? any idea if comparable to the AS&M?

check out this link: http://para.noid.org/~lj/PCM%20Tutor...litBLMinfo.htm
interesting info and will further explain the AS&M IAC passageway i was talking about.

Deenasty

My MAF is just descreened thats all. If the MAF goes bad, doesnt it shoot a code?

SlverBullet, I am not 100% sure how the passages areon the BBK, but it is worth taking a look at it. Thanks!

blkchevyz

yep.

not really sure on the gas mileage, i dont drive the car enough to know.
but i can say is my cam is a little bigger then the 306 and with this tune it has basicly no cam surge

Deenasty

well I have tried both open and closed loop, and I feel the car drives better in closed loop. But that could be that my fueling is just off in the open loop tune.

blkchevyz

yeah mine was pretty far off in open loop at first... but that was probably due to different injectors and fuel pressure.

have you had any tuning on it yet?

Deenasty

I had an open loop tune that I was playing with, and have a wideband in the car, but even at that, sometimes the AF could be wrong. What does your car run at AF wise, idle? Cruise? WOT? I just recently uploaded a PCMFORLESS file, which is a closed loop tune, and im having this issue at idle. I might just go ahead and run a closed loop PE idle tune.

blkchevyz

at idle i fattened it up, its around 13.7-14.0
i got the most vacume at that range.

cruise i just shot for 14.7.

wot is 12.9

i put it on the dyno and leaned it to around 13.1 and up and it lost power.

Deenasty

sent you a PM..

1racerdude

If it was the cam overlap wouldn't it do it on both banks????