Z28Camaro30Ann

iTrader: (15)

Ok, so working on my tune I was datalogging in datamaster. I was watching my L and S trims while I was idling....my Drivers side L Trim sits at +1.6 steady...my Pass side L Trim is almost always sitting at +18. Can someone PLEASE translate for me and tell me what the cause could be?

soundengineer

iTrader: (16)

passenger side has an exhaust leak before the o2 sensor

likely a leaky header gasket

Z28Camaro30Ann

iTrader: (15)

It isnt at the header...at least if it is I can't hear it. I will double check tomorrow when I can start the car without pissing off the neighbors lol. There isnt another place for a leak before the O2 except MAYBE at the O2 itself...

I just went over my datamaster files. At Idle is the ONLY time it is adding fuel...when I am lightly accelerating it takes away fuel from both sides, then when I am at WOT, both sides are at 0.00 the entire WOT run...as soon as I go back to idle, the driver side goes back to normal and the pass side goes back to +18 or wherever it falls. If it was an exhaust leak, wouldnt it be adding fuel through the entire power band??

Also, does the knock retard have ANYthing to do with this situation? I hope I didnt wear a hole into the header with my K-member

Does anyone want to review my datamaster logs and tell me if they see anything off other than the false knock???

Z28Camaro30Ann

iTrader: (15)

Nevermind! I just found a tutorial that told me why the O2s do not matter when I am at WOT! I am starting to understand this PCM **** lmao.

http://para.noid.org/~lj/PCM%20Tutorial/PCMtutorial.htm

BLK02WS6

iTrader: (2)

You have an exhaust leak...

flame

iTrader: (13)

If you have ruled out the exhaust leak it can be caused by a misfire. The misfiring cylinder dumps the unburnt oxygen into the exhaust and the O2 sensor sees that and commands more fuel. Your misfire could be a plug, wire, injector.........

On another note some aftermarket LT1 throttle bodies can cause split fuel trims because of the way the iac port is. Do a search on split blms in the LT1 section and I'm sure you'll find it.

salemetro

iTrader: (5)

Actually, LTFT % IS carried into the WOT fueling calculation...so it is important. They (VE/MAF) need to be dialed in as close as possible, and NO LEAKS.

soundengineer

iTrader: (16)

but only positive ltft gets carried over to WOT


Posted from LS1Tech.com App for Android

salemetro

iTrader: (5)

I should have been more specific...but yes, he could (in theory, although unlikely) be seeing as much as 18% being added at WOT based off of his current LTFT issues.

Z28Camaro30Ann

iTrader: (15)

I searched split BLM's and my IAC was WAY off...it was at 160 (wide open) and my idle had been giving me trouble. I adjusted the Stop Screw on my TB and modified the TPS and it runs MUCH better now once I got the IAC Position down to ~45 at 0% TPS...HOWEVER, my BLM's were still split. So that wasn't it. I do not hear, feel, or see ANY exhaust leaks at the header gasket and there is no other place for a leak between the block and my O2. Also under casual driving the BLM's even out.

I was still getting 12* of Knock Retard at idle dipping down to ~8 or 9 once in a while with the Spark Advance set at 32*, so I was sitting right around 20* of timing at idle with the retard...SO, I wanted to see if it would change...I dropped the Closed TPS Spark Advance to 20* and I dropped the Main Spark Advance for the ranges where I idle (50-70 kPa and 600-1000 rpms) down to 20*. Reflashed and cranked her up...Idled fine but Knock Retard was STILL at 12* dipping to ~8 or 9, so timing was right around 7* to 10* at idle. BUT, I let it idle for a minute because I saw that my BLM's had evened out!!! BEFORE I dropped the timing, my BLM's sat at 129L and 143R...This time they were BOTH at 124 and didnt move at all. I let it run for a good 10 minutes and no change.

Is it possible that I am experiencing reversion at the higher Spark Advance, or that I am losing vacuum? All SP wires are good, there is no misfire, I cant find any exhaust leak, O2 sensor is reading, I do not see or hear any vacuum leaks on the outside, kPa is right at 85 with the engine off and at 84 at WOT so I am not sensing a vacuum leak in my datalogs either...at Idle my kPa bounces between 55 and 65 kPa. Brakes work great as well. Thoughts?

salemetro

iTrader: (5)

Fighting false knock now?

Old Geezer

iTrader: (3)

"I hope I didnt wear a hole into the header with my K-member."

U say the header may have a hole worn in it due hitting the K member...Think maybe that metal to metal is a source of knock?
Header hitting on the same side as the LTFT issue??

salemetro

iTrader: (5)

Damn... I didn't even see that. Good call.

LilJayV10

iTrader: (39)

http://www.noid.org/~lj/PCM%20Tutorial/SplitBLMinfo.htm

This is on split fueling issues the with LT engines, don't if it will help or not.