Rhrcnc

Hello everyone! I'm reaching out for some assistance and guidance on tuning. I've been a owner of an HP Tuners MPVI2 for nearly 15 years now. Over that time, I've primarily used it for simple tasks like removing VATs for a few swaps and adjusting torque management. However, I've never gone much deeper into the world of tuning due to feeling unqualified.

Recently, I've embarked on a journey to expand my knowledge and skills in tuning. I've built a 2007 NNBS E38 4.8L truck with various upgrades including a VS 78/75 turbo, VS Deka 80 injectors, 3-bar EFI Source MAP sensor, Sloppy Stage 2 cam, Pac 1218 valve springs, log manifold, Walbro 450 fuel pump, stock returnless fuel rails and feed, AEM 03-300 wideband, and a 4L80 4x4 transmission with HD2 and Circle D triple-disc 3400-3600 stall converter.

After years of reading and watching countless videos on tuning, I finally got the truck up and running, albeit not perfectly. I used a file from the Sloppy Mechanics wiki ("Jaimie's Truck") to get started, but the truck is running extremely rich, with eye-burning exhaust fumes and barely idling. I suspect the issue lies in the fuel injector scaling, especially considering Denmah's use of stock decapped injectors versus my Deka 80s.

I've been trying to wrap my head around injector scaling, but it's still a bit confusing. I've come across various approaches, from applying a single scaling factor across the entire injector flow rate versus pressure delta, to finding specific injector data and copying it. I've downloaded multiple Deka 80 tables and tunes, but I'm still uncertain about what steps to take.

While I'm open to paying someone to tune the truck, I'm also eager to learn and don't mind experimenting on my own. I've been in the automotive industry my entire life, transitioning from a lube tech and flat-rate technician to leading the diagnostic division of a reputable independent repair shop. Fortunately, I have access to a Mustang dyno primarily for testing and diagnostics, which I can utilize as needed.

I appreciate anyone who took the time to read through this, and I'm grateful for any assistance or advice offered. I'm still relatively new to this journey, so I ask for your patience as I continue to learn and grow.

dw456post

Your injector offset Pressure vs IGNV table is still setup like a return system. You need to change that to a returnless--- You will have to retune the VE when you do that.;
You need to post a log so we can see what it is doing.
Did you do the 43# pressure for the 80# injector not being under the 63# limit? Those injectors like 58#---and so does the engine. It's very easy to set up those larger injectors to use in that computer. Double stoich, Half IFR, Half IVT Terms. Make sure and get the correct injector data for 400KPA (58#), for your returnless system. Flow Rate vs Pressure, Offset vs Pressure vs IGNV, Short Pulse limit, Min Injector Pulse, Short pulse adder., Make sure the 5 things are correct and do not change them to adjust your tune--they have to stay the same.

dw456post

Go to aacorvette and they have the Siemens/Deka data for your injectors and E38. for 58#

Rhrcnc

I greatly value the insights provided! Presently, I'm working with a remote tuner, although I remain uncertain about the outcomes thus far. The alterations you discussed above have not been implemented, further adding to my confusion. The truck continues to struggle with idling, and based on the narrow bands it's running lean now. While I can share a log, I hesitate to disclose his tune, assuming he's still refining it.

gametech

iTrader: (1)

If putting in ALL of the correct injector data was not the first thing the tuner did, you should run away. If they do not know how to scale the tune to avoid the hardcoded size limits, run away.

Rhrcnc

Well just found out the remote tuner I'm working with is a scammer. I should have known. From what could tell he didn't scale the injectors correctly and now the truck is worse than with the original denmah tune. I guess I will start over.

G Atsma

Put the scammer's name up here. The world should know.

Rhrcnc

There's a whole thread on Facebook about this.

https://www.facebook.com/share/p/spvtacvyuiSMCFn1/?mibextid=oFDknk

Rhrcnc

I am seeking advice regarding my current vehicle setup above. Specifically, I am considering whether I should replace the E38 PCM t42 TCM with a P01 or P59 in order to achieve proper tuning. I have already worked with two different remote tuners, but neither has been able to get the truck running correctly. Furthermore, I have been informed that the E38 PCM is not capable of handling my setup and that the tcm cannot be used with a 4L80E transmission. However, I have seen multiple instances of people successfully running an E38 PCM and t42 TCM with a 4L80E transmission. Given my current challenges, can anyone recommend a remote tuner who might be able to resolve this issue? Alternatively, should I consider converting to a different PCM system? Any insights or recommendations would be greatly appreciated.

minytrker

iTrader: (13)

Your combo isnt anything hard to tune, What you posted is way off. Start over with a stock file and tune it normally, you dont have to do custom os on e38's for boost.

NicD

iTrader: (7)

Yeah, doesn't seem like a big deal to tune that.

As long as you still have the FPCM module in the vehicle along with the fuel pressure sensor you would want to keep your IFR setup as "normal" with a slope like OE in the tune so don't flatten it out like somebody suggested. This way it will still be able to compensate for any injector pressure differentials, regardless if you have a vacuum/boost reference hooked up with a return system or not.

Do you still have the MAF in there or is there a reason you went speed density?

Post up your stock file as well for comparison and list all mods you have.

Rhrcnc

I was under the impression that speed density is better, and easier to to tune, to be honest.
2007 NNBS E38 4.8L truck VS 78/75 turbo, VS Deka 80 injectors, 3-bar EFI Source MAP sensor, Sloppy Stage 2 cam, Pac 1218 valve springs, log manifold, Walbro 450 fuel pump, stock returnless fuel rails and feed, AEM 03-300 wideband, and a 4L80 4x4 transmission with HD2 and Circle D triple-disc 3400-3600 stall converter.

NicD

iTrader: (7)

I haven't had a chance to do any comparisons yet but keeping the MAF is quite a bit easier, assuming the MAF is in a good position in the charge piping. Do you still have the MAF in place?

NicD

iTrader: (7)

OK I just had a quick chance to briefly go through it and it's no bueno. Injectors aren't scaled at all, no wonder it's pig rich. I would keep the custom OS either way just for ease of manipulating the VE tables or if you have the MAF you can switch back to that since the custom OS has the extended MAF table in it as well. Actually I really don't like anything done in that tune at this point as none of it is done correctly. Torque management is disabled entirely which I wouldn't do even with a 4L80.

You don't have a competent tuner in your area at all?

Rhrcnc

Here is the current tune it allows the engine to idle decent and respond to slight throttle input. The AFR at idle is approximately 14.2. I did not install a MAF sensor. Instead, I relocated the IAT sensor wires and installed the IAT sensor in the charge pipe a few inches before the throttle body.

Despite consulting with a few local tuners, I remain uncertain about their advice regarding injector scaling. Both suggested that injector scaling was unnecessary, which contradicts some of the information I've encountered.

I am eager to learn the intricacies of tuning myself, but the conflicting advice has left me confused. Additionally, I often find myself at a loss with some of the instructions I receive, as I have no idea what certain procedures or terms actually mean.