Help with csp5 2800rpm fuel issue?

[superwagon]

I was hoping somebody might help me out. I have not been able to figure out why I keep loosing mm3 and duration but noticed it seems to be tied to 2800 rpm. I am attaching my csp5 tune file and two logs. CMB_0084 log is starting the pull in overdrive and it downshifts to 3rd unlocked and then locks up. If you watch commanded mm3 and duration drops once rpms hit 2800. The CMB_086 log I start the pull in tow haul locked in 3rd so the rpms dont jump above the 2800 and it seems to fuel much better until I reach that 2800 again?
The tune is csp5 on tune 3. I would appreciate any help or ideas on this!
Thanks!
Doug

[Alex S.]

i've founght with similar issues and still do on some tunes. I would gladdly take a look at the file, however Ive not updated my EFI live in awhile so I can't open your tune file. I have a similar higher rpm issue with the tune I've playing with in my truck now. Above 26-2800 rpm it starts pulling back CMD.Fuel. The tune calls for 150 but usually only hit mid-high 140's and it starts going down with rpm until the trans shifts and rpms drop and then it shoots back up and starts doing the same thing once the next gear gets into that rpm range. Every once in awhile it will go to 150mm3 and stay there as long as I hold the pedal down and be a nice flat line on the log, but I'm not sure why. I have all but the boost and density limiters set to 150mm3 and those are both at 150mm3 in higher rpms. If I get a chance to update EFI later today I'll look and see if I see anything, but I'm no pro either. It's hard to get information on this kinda stuff. I've had some help from Les and the guys at anarchy, which I'm grateful for, but even they were pretty general and vague in anwering questions. I have asked about this limiter issure previously and never got much input from anyone, perhaps you'll have better luck.

[superwagon]

I would appreciate another set of eyes. Came across another thread that mentioned MINJSTAT_F so I monitored and found it switching to 12 when I get to 2800 and fueling starts to go south. From what I gather this indicates a rpm limiter in effect? Not sure what other numbers mean? 7= no limiter, 15= altitude limiter, 12= rpm limiter. Difficult to find much info on this but I was able to remedy a major defuel I had that related to 15.

[30 RUM]

Superwagon,

Take the truck out and Log Engine Load (I wish it was in EDA). I have a feeling you will see the Load decrease as RPM increases past 2800. Once Load starts falling off so does fuel demand. On my truck 07 5.9 manual, it would pull down to 75% load at 3400 Rpm. We do not have access to a load reference table with EFI Live.

[superwagon]

Thanks 30 Rum,

I will try to get a log with load monitored and see if it's doing the same as yours.

I have gotten a few other suggestions and a tune file to try but I haven't been able to get time to try anything since I posted this.
Thanks again!

[30 RUM]

No problem, with out looking at the tune yet, that is the first thing that comes to mind. When I get some time I will go through your tune and see if anything jumps out at me.

[kyle027]

Did this problem get resolved? Cause I'm having the same issue.

[superwagon]

I had to stop pushing my truck so hard until the transmission got built. I ran into some issues with my trans build and sent it out to be gone through again. When I get it back I plan on revisiting this.

[CapitalDiesel]

im having this issue to, noticed it when i logged my dyno run, mm^3 commanded just starts dropping off even though tps is at 100% and duration limiters are disabled. also happens right around 2800 in OD...subscribing.

[computerjlt]

i too am having the same issue as the OP....

advice i got was "tune around it" but it would be nice to hold commanded to redline (especially if its bumped up)