crank, no start after changing injector data

[djamesp]

03 silverado 4.8 next gen 7875 & 4l80e 3bar os. was running ok enough to tune by, then i changed to some less-sketchy-looking deka 80 data, flashed, no start at all or sputters then dies. Flashed back, still no start. Verified that i didnt save over the injector data from the previous tune & that no other other changes were made, all good. but now besides not running theres no maf failure code (divorced iat, no maf on truck), no codes at all. The only weird thing i saw on the scanner was while cranking commanded afr was oscillating between 0 and some ridiculous value like 2.5:1-3:1.

by now ive flashed multiple known-good revisions, same story. this is all new to me nd i cant seem to find what the hell would do that at all, much less a fix. posting log/tune maybe someone could take a look at for me, id very much appreciate it. please ignore the AFR/FPR readouts, was still dialing in the offsets when this all happened, fuel pressure is steady 58psi and AEM gauge reads 14-15 while cranking. just reverted to stock os for the 4l80 segment swap and reflashed the 3bar, so there aren't that many changes ive even made?

really would appreciate some insight, thanks!

05 silv 80lb 7875 12-29-23.hpt
23-02-04 13-04-30.hpl

[5FDP]

The min injector pulse is set to zero, that isn't right.

What MAP sensor is that?

[djamesp]

That it is, not sure when that happened... Changing it back to 0.5927 from the data sheet is giving me the same no start. Map sensor is https://speedmaxinnovation.com/produ...m4-lm7-l59-lr4 . I bench tested it before installing and their numbers were right on, KOEO reads right at 105ish.

[5FDP]

Reading 105 would be too high but that still wouldn't cause a no start. You'll need to manual adjust the numbers so that it reads correctly for your altitude. Sea level would be ~100kpa.

[blindsquirrel]

VE table didn't get done right after the OS change. Data from the original 105kPa row is supposed to go into the new table's 100ka row, not the last row. The tables have the same number of cells but you can't just directly paste the entire table.

[djamesp]

Right, i should have picked a better file - that one got hammered was after digging out old tunes/copying sections/reflashing and getting nowhere fast haha. Does this look better as far as the VE goes?
05 silv 80lb 7875 02-04-23.hpt

and i misspoke, it was 100kpa not 105 @ 1.31V from the map.

just noticed maf is logging a non-zero value where it was zero in previous logs. but there's no maf? would that not fail it right from the gate?

[blindsquirrel]

You have MAF Fail High at 1 Hz, how's it supposed to meet that with the MAF removed? If it were still installed it would, but not if it's gone. Try 0 Hz. It has to set either P0102 (still installed but failed) or both P0102/P0103 (if completely removed) for the PCM to switch over to speed density. If it isn't setting those codes, it's not in SD, and with no MAF if it's not in SD it isn't going to run. I'm not pinning that as the definite cause because logfiles sometimes don't show all the codes in the 'Details' tab if it's the first log after a reflash, but it's something to check.

Logs are showing an injector pulsewidth of only 1.3-1.4ms during cranking, that seems low. Does it run if you feed it some brake cleaner (make sure it's the spicy kind (flammable))?

[djamesp]

That definitely makes sense, and it fired up with brake cleaner no problem. Changed maf fail to 0 and sure enough it took right off failed maf, etc. Thanks to both of ya for looking in to it! I attached one more log, all this started from me trying to nail down why going from park to drive the AEM gauge shoots all the way to the max, barely stays running, etc. but I don't see any evidence of this in the AFR or AFR error log? its always done it & usually ~1min goes by and im back to just barely rich sitting at a stop in gear. Can't figure out what would be doing that, am i missing something obvious?

23-02-05 13-39-24.hpl