Help understanding cranking steps/tables referenced

[martincneal]

I'll start off by saying I'm fairly new to this so I'm still a newb. Thanks to the forums, I've learned a ton and I have my car dialed in fairly well except for warm/hot starts. From my understanding, my tune is an OL MAF and PE tune.

So far, I've played with Startup Airflow and Cranking VE. The car cranks right up at every temperature and dies about a second later. I've taken a log, which I'm having an issue there as well, but I think it has the information needed to help. If you look at the log I've attached, on the first crank you'll noticed the Commanded A/F is 12.68 during crank, but as soon as the motor catches, the Commanded A/F drops to 9.25 or so.

What I need help with is, what is happening at the 9.25 A/F? Is another table being referenced? Is the MAF being referenced at that point? Btw, I'm still working on my MAF curve b\c the previous tuner didn't have the correct injector data or EOIT and the car was super rich after correcting the data.

Any other pointers or information will be well-received. I'm taking something someone else did and trying to make it correct and better. Another question I have which is not as important is how does the PE Enrichment Enablers work. Do they all have to be satisfied in order for PE Enrichment to enable or just one or the other?

Car Info:
2012 Camaro SS
Forged 6.0
.620/.620 244/249 LSA 116+3
54/56 Twin Turbo
Stock Heads

Tune and Log attached.

Thanks,
Martin

[martincneal]

Maybe I should ask a different way. Is the MAF immediately referenced after crank since my Dynamic Airflow High RPM Disable is set to 100 RPM?

[GHuggins]

Why did you advance the injection timing so much instead of retarding it? When did the starting issue start? If you give it throttle will it keep running? Basically your gains, open loop tables and VE are directly referenced after startup - MAF comes in about 5 seconds afterword's...

[martincneal]

Thank you for replying.

I still don't fully understand Injection Timing, but I did a lot of reading and found a lot of calculators. I thought since my ridiculous raw fuel smell went away that I was going on the right direction. I'm attaching what was in the tune before I started doing research. I don't mind trying something you suggest.

The starting issue was bad while I had my RHS 427 in the car with a milder cam. It only got worse when I put the 370 in with a hotter cam. Yes, if I catch it, it will keep running when I give it throttle. It has gotten better since I've been playing with the Crank Fuel and Startup Airflow.

But your question on injection timing really has me second guessing myself now. If you don't mind, what you put for the injection timing?

Thanks again for the reply.

OriginalEOIT.PNG

[GHuggins]

You need to go back to a stock tune and start over instead of trying to work around the current problem - your engine displacement hasn't even been changed in the tune for the bigger motor...

[martincneal]

The 427 is gone, small crack in the block. Going in a different ride now after it's repaired. The 370 is in now, which is close to the stock 376. But you are right, my tuner never changed the engine displacement for the 427 while it was in.

Stock tune! ...that scares me! Thanks for your input. I may consider that after I'm more comfortable with timing.

[melition]

I do have to agree on eoit being confusing. My trucks raw smell goes away if i advanced it 20-30 degrees and ran better seemingly. Ive read that it needs to be retarded so i just set it back to stock

[GHuggins]

Well, that's why every setup isn't the same - if it likes more advanced then go more advanced... As for the stock tune - go back to stock ls3 and dial timing in more for a boosted setup - also change the airmass scaling for boost and then injectors and map for what's in it...

[melition]

That makes sense. Advancing it moves the beginning of the injection further away from the intake valve opening correct? Or is that backwards.

[martincneal]

I got it! Huggins you said exactly what I needed to hear.

My brain would not let me differentiate between SOIT and EOIT. After reading for the last hour or so and messing with more calculators, comparing the stock tune, etc. It looks like my EOIT/Normal ECT should be around 70. That's the reason I had the EOIT advanced is because I was stuck on EOIT being SOIT. I'm guessing the raw fuel smell went away because I was dumping fuel on a closed exhaust valve.

I can see how making that change warrants going back to the stock LS3 tune. I guess I have some weekend work ahead of me.

One more question for any experienced tuner and I know it's just an opinion. Is it better to go with a VE/MAF tune? Or MAF Only? I've read that tuning low RPM is easier in VE and then have the MAF pick up from 4000 RPM on.

[melition]

Tried many different ways and the only way to get it running the way i wanted was a vve tune and maf tune

[martincneal]

I was kind of leaning towards that. With the existing tune, I'm having a hard time getting the idle A/F leaner. I ended up having to raise the Airflow Minimum, which I didn't feel like I should have to. It was idling around 12.4 and now I have it around 15.1-15.8. I guess I'll tune VE and then tune MAF so they've both dialed in and decide later.

[melition]

i have a similar cam without the turbos, but i run much less base airflow and i actually run lean at idle from 14-16. I believe my neutral base airflow is around 9.2, but tuning the ve really helped that. before with that kind of base airflow it would run like shit, and now its much smoother.