LS3 with TVS2300 MAF tuning help

[b85chevy]

I am attempting to learn how to tune my own vehicle, this is new to me but I have read a lot and watched a bunch of videos so I am somewhat familiar at this point. Can someone help me understand what is causing the significant measured EQ ratio drop starting at 2,100 rpm? Note that commanded EQ is 1.0 and measured is 0.65 at the lowest point. This happens with vehicle in neutral while engine is smoothly ramped up, it is consistent, happens every time. I discovered it while attempting to log MAF error data using a tune I created which forces open loop, disables VE, COT, LTFT, CFCO, sets open loop gains to 1, PE throttle hot set to 60%. This also happens with everything enabled as is shown in the attached picture.

Vehicle is a 2017 Chevrolet SS, 6MT, TVS2300, VCM CAI, regular gas

Thank you!

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[GHuggins]

2017? So it's an LT1 and not an LS3? This is not an engine to be learning on or platform to be self learning on especially with those kind of modifications. Just getting the fuel density multiplier table dialed in requires a lot of experience and know how not to mention a considerable amount of time and that's an absolute must with that setup. Otherwise you'll need to post tune and corresponding logs showing what you're talking about

[b85chevy]

2017 SS, the sedan, is an LS3.

[GHuggins]

OK, I read it pretty quick and thought you meant SS camaro. You still need to post a log and current tune It's under "Go Advanced" "manage attachments" just in case you didn't know.

[b85chevy]

Thanks for pointing out where attach is, post updated with tune and log.

[Proxses]

Hitting minimum injector pulse. Not sure why it's set to 1.555 at 2000rpm....

[Alvin]

I also think its hitting the injector pulse min.

But you are going to see spikes rich when you lift off the gas pedal. That one is a pretty extreme one though.

[b85chevy]

Thank you both. I will go read about how to properly set that, I wonder if it is set like that for the bypass valve transition on the TVS2300.

[b85chevy]

Injector pulse min is definitely the cause, I set everything to one and measured lambda stays near 1 at those RPMs. I am going to move this to the bottom of my to do list unless someone has some suggestions of where to start.

Problem #2. With a tune that forces open loop, disables VE, COT, LTFT, CFCO, sets open loop gains to 1, PE throttle hot set to 60%. Hot starts almost always die immediately after starting during the return to idle speed. I attached a log where the engine almost dies then recovers. IATs or heatsoak may be a contributing factor. I adjusted the Airflow vs. Frequency table from 3000 to 3900 based on the MAF Error % while the car is in neutral and have that close to measured lambda 1, this doesn't seem to resolve the issue. Of note, if I feather the throttle and get the engine to idle speed for 10-15 seconds, it will sit there and idle fine forever after that.

Appreciate the help as I learn this.

[07GTS]

u cant disable the VE its always in use in some conditions unless u zero it out and i wouldnt recommend that

[b85chevy]

Alright, I fixed the open loop hot start issue by adjusting the startup airflow and airflow final minimum. The next issue is that after hot start the engine is rich for a few minutes, what is causing that? Lambda slowly returns to 1.0, during this rich period if I gently rev the engine and let off the engine will almost stall.

P.S. Sorry for all the questions at once.

[b85chevy]

u cant disable the VE its always in use in some conditions unless u zero it out and i wouldnt recommend that

Oh. Alright, so maybe I am at a point where I should do the rest of the MAF tuning then.

[07GTS]

if u get most of it done with the maf then after its decent if u get the VE dialed in it will make it that bit better overall, hot starts if u have changed the injectors u will prob have to adjust the injector tip temp offset to get it better also dont zero it out, or if u have just done a flash then give it about 10 mins of running before u start to get good data

[GHuggins]

This is a canned tune from magnuson with some minor changes for their 2300 for a vette if that would help you any. There are tables in this like the ivt table that need altering, but it'll be a pretty good place for you to start. The changes I made were done WAYYY before I really knew how to tune, but again this is still to this day daily driven to my knowledge.

[GHuggins]

Also don't waste your time with the open loop tuning - you've got a lot of tables in there for open loop gains that need to be adjusted while tuning.

[b85chevy]

Thank you both for the help and tune for me to reference, I'll keep working on it

[b85chevy]

I need more guidance please. In the attached log there is a lean spike at 3,300 RPM which I cannot explain. I have tried changing fuel pump duty cycle and min pressures, it has no affect on it. It is repeatable, although it isn't always at the exact MAF flow. I also think the MAF is dialed in pretty well at this point. Thank you.

[07GTS]

disable desoot mode see if that fixes it, its at the bottom of the injector tab

[b85chevy]

Awesome, that was it.