enoniam

Well, the Cylinder Air looks pretty flat leading up to the lean spike.

There may still be a problem with the Injector calibration but there looks to be a problem related to the calculation of the Cylinder Air. VE table or something related to the way the PCM calculates Cylinder Air.

schpenxel

It's in MAF only but that's something else I'd change too...

I'd increase MAF and VE tables in that spot by a significant amount, say 6-8%, just to see if it responds like it should as a first step

Could also just do some PE "raping" and increase fueling that way just as a test. Obviously don't leave it that way, but it'd be interesting to see what it does.

CTD

Thanks for posting the screen shots

I'm just a tad over 600rw & have tried several sets of injectors(not the posted) including ID 1000's, FIC, LS3/7 & LS9. The only issue I ever had was the sudden fuel run out with LS3/7 & some drive-ability concerns with the FIC & LS9. My goal has been to get a higher IDC 80% plus. Currently deatschwerks injectors, I believe 43lbs with good results. LS9's are inexpensive, good data just to try if their is a suspicion.

I do remember a similar problem to this 2 or 3 years back. My cam was 17* of overlap & I was struggling with some manners. Speaking with a couple of different tuners trying different files & something like this issue showed. I'm going to say it showed out of nowhere & most likely was a bug or glitch in one of the files that had been sent to me.

We backed up into one of my own previous files, did an "entire rewrite" & as mysteriously as it appeared, it disappeared. This would be my very first suggestion.....easy to try. You just need a previous known good file.

My question would be as it is, what happens if you keep the motor just below PE & drive thru that 3500rpm area? Or is it a PE only issue?

As well easy to try would be swapping banks, I would do injectors & ignition just to see if the problem moves.

What a nightmare problem fun though when it's solved.

schpenxel

Lean spot happens on both banks but is worse on one side. Without a wideband on both banks I'm not really sure how different they are. NB O2's are so sensitive around stoich it doesn't take much to get them to swing from ~700mv to 200'ish

CTD

That's why I suggested the bank to bank swap, I not sure I would believe the small change as being real........may just be a result of the bank that really indicates a lean condition.

Your comments about the KR make wonder if the tuner tried a blanket removal of 5 or 6* in the higher load area just to see if there is any connection.

enoniam

It seems pretty conclusive from the data though that up until the lean spike the fuel injector pulse widths are not keeping up with increase in cylinder air. That's the root of the problem.

If you swap and the data flips banks are you any closer to solving the problem?

RonSSNova

Have you monitored fuel pressure?

tblu92

If you are looking at 02 voltages from your data logger most likely thry are from your stock narrowband 02 readings and NOT your wideband readings---
When your engine is in power enrichment you cannot use the stock narowband readings as an indication of AFR ratios as the naroowband 02's are not being used at all to command your AFR ratio and are turned OFF---any readings you get of 02 voltages are by accident
To get proper accurate wideband readings with your data logger you must select a PID the incorporates your brand of wideband and wire it into your tuner correctly on the proper wire leads as instructed by the manufacturer

Fastbird

But you can still reference the feedback voltages from the stock O2's to get a head on what's happening which is all I was doing. I never referenced a specific AFR, just said it was obvious it went lean which the voltages on the stock O2's reflected.

schpenxel

Ignore him.