Help, stumped on getting this thing running right

6.0 LQ4
227/234 114lsa
stock heads
ls6 intake
equal length headers
33lb injectors
50ish psi fuel pressure


Got the car put together and running good. Drove it around for a while and put it away after the baby was born.

Car ran and drove fine and pulled like it should (albeit it was about 12.9 wot on wideband.) until it was parked.

Alternator went bad from sitting so I swapped it out. Decided to take it on its longest trip since it was built. (25 miles or so)

Now the car runs like dog crap. Idles fine. Has a disgusting hesitation now and my charts seem to have flipped since I drove it that day. I'll attach my current tune. I haven't made any changes as I wasn't convinced it was tune related but i've gone over every aspect I can think of. Maybe someone sees something I'm missing?

I will also attach a few logs from when it ran fine to now.

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The fueling is way off. You need dial in you Maf & VE table. I don't know what fuel your using, but your timing table is very conservative too.

Running vpower 93

I'm questioning myself as to whether or not it ran fine on this tune due to the old alternator not doing what it's supposed to. The new alternator seems to be the only thing that has changed between how it ran and how it runs now.

Fueling is stock and untouched as far as I know. Planning on going speed density so it looks like I need to go ahead and do that and just get to work on the tune.

Quote:

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Originally Posted by Grimaces14

6.0 LQ4
227/234 114lsa
stock heads
ls6 intake
equal length headers
33lb injectors
50ish psi fuel pressure


Got the car put together and running good. Drove it around for a while and put it away after the baby was born.

Car ran and drove fine and pulled like it should (albeit it was about 12.9 wot on wideband.) until it was parked.

Alternator went bad from sitting so I swapped it out. Decided to take it on its longest trip since it was built. (25 miles or so)

Now the car runs like dog crap. Idles fine. Has a disgusting hesitation now and my charts seem to have flipped since I drove it that day. I'll attach my current tune. I haven't made any changes as I wasn't convinced it was tune related but i've gone over every aspect I can think of. Maybe someone sees something I'm missing?

I will also attach a few logs from when it ran fine to now.

Attachment 131470Attachment 131471Attachment 131472Attachment 131473Attachment 131474Attachment 131475

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Your VE table will need some work. Not sure how much you've tuned it yet, but it will need some fuel subtracted at lower RPM's and fuel added at higher RPM's. It's all in the fuel trims, they're pulling pretty negative in a lot of spots.
However, to tune the VE you want to be in speed density mode, so fail the MAF (lots of videos on YT on how to do that) and do another data log. You can pull a bit of fuel under 2800 and add some above it. Then do a good data log, reset fuel trims and use the part throttle STFT+LTFT numbers (set up a graph in VCM scanner with same axes as your VE table) to paste special, multiply by percent into your VE table and repeat until low error. Use the wideband Eq error and make another graph to help tune WOT and high RPM's. Then you can move onto MAF using a similar strategy.

You should also turn of COT and DFCO to make your tuning a bit easier. The other guy mentioned your timing table, but I wouldn't start adding timing until your fueling is dialed in. It doesn't look THAT conservative, and in fact you have KR in some spots so might want to reduce in those areas, at least temporarily.

I messed with it a bit today in SD trying to see if I can get something going. I'm still running in to a misfire in the low rpm range part throttle acceleration. I'm starting to wonder if I have a bad injector. My logs are pulling extremely lean which doesn't make sense at all tbh. I'd expect a rich condition as opposed to a lean condition. As far as timing goes I think i'm okay where I'm at. This thing is driving me up a wall. I'm considering pulling the injectors and checking the spray pattern on them. Not sure what else could have caused me to go from pretty rich to extremely lean in a matter of the car sitting and me swapping the alternator. Doubling back over data now. Racking my brain.

Side note. I am still pulling very lean on deceleration almost like DFCO is still enabled even though I have gone through everything to make sure it is disabled.

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Also for consideration purposes I'm considering adding about 15% to the VE table since it just struck me that this is a stock 5.7 VE table and I have a 6.0 with a stick and headers. Any input is greatly appreciated. I feel like I'm over complicating this but I also don't understand how I go from rich to lean. Also everything in the fuel system is brand new. Running a AEM 340 fuel pump, new 30# injectors and brand new regulator.

Misfires show up as lean. O2's don't detect unburned fuel, they detect oxygen. When a cylinder doesn't fire it sends all that unburned oxygen right down the pipe.

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Originally Posted by blindsquirrel

Misfires show up as lean. O2's don't detect unburned fuel, they detect oxygen. When a cylinder doesn't fire it sends all that unburned oxygen right down the pipe.

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At this point i guess my question would be what would I do to narrow down the misfire? I'm throwing 0 codes and with "Current misfire cylinder x" logging I'm not logging any misfires. Would I have to log Misfire history?

after 2 long days of this im going to take the injectors to be flow tested. It's the only piece of the puzzle I can imagine would be bringing me issues. Thanks everyone. Will report back.

If you have doubts about the injector data, for anyone to check that for you you'd need to state which injectors they are. "33lb" (or "30lb", in post#6) isn't enough for somebody who isn't you to identify them.

Quote:

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Originally Posted by blindsquirrel

If you have doubts about the injector data, for anyone to check that for you you'd need to state which injectors they are. "33lb" (or "30lb", in post#6) isn't enough for somebody who isn't you to identify them.

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I'm not convinced it's an issue with injector data. Ran fine on the same injector date previously before I was able to get to my MAF and SD tuning. I'm sure whatever I have going on will trace back to this misfire condition. Runs the same in open loop so I doubt my o2's are to blame. I'm heavily leaning on one of my injectors failing to do the thing under load. Have to get a new set and see what the deal is.

I'm ONLY breaking up under load in 3rd or 4th gear. Idk about 5th because I have a long gearset and haven't been able to verify without fault but anything past 25%ish on tps i'm getting breakup in 3rd. 4th is even lower than that. I have changed coils and plugs, fuel pressure seems to be fine. Have to get a reading tomorrow in regards to while i'm driving and having the issue before I pull the trigger on a new set of injectors. If I'm dropping fuel pressure then I know where to look but both the pump and regulator have under 1k miles on them.

Pulling 0 codes.