LMM: Commanded Rail Pressure not following tuning changes

[monster50iii]

Seems like most threads run to a dead-end. I cannot for the life of me get commanded rail pressure to follow what I enter into the tune( only in the DSP5 format). My base tune in DSP5 format follows rail pressure like it should, but 1-4 do not..especially between 1000-1850rpms. I'm about 30mpa low. IS this an OS issue, fuel flow base issue (I played with this alot with not alot of success), just not sure what direction to go with this. I've tried a few different base tunes but I get the same result every time. Any guidance would be greatly appreciated.

 

[THEFERMANATOR]

Many have reported that the 8594 OS in the early LMM's seems to stay locked onto the transient tables, and does just as you describe. Are just changing the A, B, and C tables, or also the transient. I also know I read YEARS back about some having it staying locked to the transient table for the base tune. Check your logs and see if you're staying on the transient table.

 

[N2BRK]

And make sure that the egr is off. Don't click the option to shut it off - leave it set to on, but change the parameters so it will not come on

 

[monster50iii]

Once I found this issue, I copied and pasted the same fuel pressure table to all the a-b-c & transient tables. Programs 1-4 dont even follow the base tune's fuel pressure at all. Fire the truck up, and it'll be idling in the 6,000psi range..it'll bounce from 5,800-6,000. As soon as you idle it up to 900rpms desired drops to 5,000psi, and will hang there until almost 2000rpm. This is all in neutral of course just to verify for talking sake. Hold rpms at say 1500, and rail is around 5000psi, switch to the base tune and it jumps up to 9000psi. So it isnt following any of the tables in the base tune. It must be reverting to something else that efi live cant see. I just dont know why, or how to manipulate it to do what I want.

My truck is the 8594 OS. I noticed the Engine Operation numbers etc are much different on my stock tune file from what what Mark was using for his tunes. I keep thinking its my base tune file. Not sure if this is something someone like myself can alter or if it is something "special" and to get this base file you need to be with the right people kind of thing.

N2BRK - Thanks for the advice, I will try that!

P.S. - loaded one of the 5 tunes in by itself and it runs as it should. Sent an email to efi live about this issue and they recommended I contact the dealer I bought the V2 from . Seems like it might be a software issue more so than a tuning issue?

 

[Harbin_22]

It's software.

 

[monster50iii]

Well somehow the professional tuners have found a way around it. I'm guessing it is all in the base tune. Not sure if there is a way to modify the base tunes to that extent or if someone really smart figured it out and shared it with the big guys etc..

For now the single tune will have to do!

 

[IOWA LLY]

Your better off running a single tune instead of a DSP5 anyway. In my opinion.


Sent from my iPhone using Tapatalk Pro

 

[monster50iii]

I agree, for the transmissions sake anyway. Just bothers me that I cant get the RP to work like it should. I know I flashed well over 100 tunes into the truck trying to solve the issue.

Question though; if this is a software issue, why the heck hasnt efi live done something about it? All their doing is putting up a major wall that us average joes can't climb.

 

[SickLL7Crenshaw]

What build are you running?? I have tuned 5 LMMs the past two weeks with zero problems and I'm currently running the latest build.

 

[monster50iii]

Is this what you were after?

 

[SickLL7Crenshaw]

No, software build. Are you running the Feb, April, or the April beta build that was released 2 weeks ago or older builds?? If your running the Feb V8 316 build and V7 323 build they had several issues with flashing via BBX and V8. All is fixed now with the April builds. Also just to let everyone know the April Beta that was posted two weeks ago by Blacky, it took 9:25 to full flash the E54 (LB7) controller, April beta 1 from 4 weeks ago did not do this.

 

[monster50iii]

1. Updated to the beta software - Thanks Sick!
2. Changed EGR settings

Same end result, however it is a "bit" better...but still way off. I put the truck in gear, and brake boosted it on up in rpms. I got to the the cell that was requesting 143mpa, yet the log showed it was requesting 50mpa. It remains a mystery..

 

[2004LB7]

Don't forget your limiting tables and multipliers. Since only so many tables can be included in the DSP tunes, the base multiplier tables are still used. And remember, 50 mpa multiplied by xx multiplier is diferant then 80 mpa multiplied by the same xx multiplier. If you are using a different mpa number in your DSP then you will get a different outcome. These are often missed so double check them

 

[N2BRK]

might not matter, but as an aside: truck in gear and brake applied... did you remove/reduce BTM?

 

[THEFERMANATOR]

Also keep in mind there are stopped idle rail pressure tables we don't have access to. When you're sitting still idling, it will run a different table. The tables we have are for when moving. I know there was a thread around here a few years back saying how you could increase rail pressure at idle. You did it through one of the multipliers as the rail pressure table is scaled for those areas, but not used until moving.

 

[monster50iii]

Here is one of the updated tunes I've been using. This is obviously not a DSP5 tune, but it would be the same style of tune I would use to make a DSP5 file. As you'll see, I have tried taking most of the multipliers out of the equation (maybe this is causing some issues idk..).