2005 4.8 turbo+ 60lb injectors erratic behavior

[ddnspider]

See this thread for reference:

https://ls1tech.com/forums/fueling-injection/1964340-05-sierra-1500-60lb-injector-olmaf-tune-issues.html

I ran into an issue where the AFR is all over the place in OLMAF even while holding a steady load/throttle cell in the MAF transfer function. I want to rule out a tune issue that I have missed a specific injector data table. Could someone take a look at the injector data and confirm Im not missing something blatantly? This is a first draft tune just to get logging. Any help is much appreciated.

24319

[joecar]

I read that thread and you do need table B9021.

But I see you said it made little/no difference... some of the other injector tables msy need adjusting.

[statesman]

You've got a serious problem with lean tip in and rich tip out. Fix that first and then you'll get a clearer picture of what's happening with your overall fueling.

[joecar]

Good point by statesman.

[ddnspider]

I believe I do have to sort out transients, but the fact that I can hold a cell in the MAF curve and watch the AFR move back and forth from 10-18 tells me that this isn't just a "dial in the MAF curve" issue. There's something fundamentally wrong, and it feels like more than the tune. I am using tall EV1 type 60 lb injectors with multec 2 adapter harnesses. I buzzed out continuity across the adapter harnesses and everything appears ok. If I incorporated B2901 and saw no change, then it seems like either I have bad injectors or wonky fuel pressure. Unless one of you guys saw something WAY off in the injector data/tune by chance?

[ddnspider]

24320Check out this log.

[statesman]

What steps have you taken to identify the cause of the problem?

[ddnspider]

What steps have you taken to identify the cause of the problem?
I think I found my issue....the MAF housing separated. I think it's been a post MAF leak this whole time and progressively separated more and more until the whole thing split in half finally and revealed itself! I'm converting to an Ls7 MAF this weekend and will report back. I also have B2901 incorporated. Solid fuel pressure has been verified.

[statesman]

I think I found my issue....the MAF housing separated.

Unusual problem. Good that you found it.

[ddnspider]

Unusual problem. Good that you found it.

I'm not out of the woods yet, it didn't fix the issue. However I found the BOV stuck open, even though its pre MAF its close to it. I also did some reading that putting EV1 style injectors in a truck intake requires thicker o rings. I have those on order and fixed the BOV. More to come.

[ddnspider]

Ive made some progress, but still running into idle issues. Latest tune attached and updated comments in this thread. See the oscillation at idle? Im guessing its either tune or MAF turbulence. Any ideas?


https://ls1tech.com/forums/fueling-injection/1964340-05-sierra-1500-60lb-injector-olmaf-tune-issues-2.html

2433724336

[nonnieselman]

How is the MAF mounted? As in where is it mounted in the air stream?

[ddnspider]

Turns out a failing MAF. Bad injector data, and turbulence sent me on a wild goose chase. All good new and I'm tuning the MAF!