2009 6.7 something is causing defueling

[computerjlt]

I'm working on an 09 6.7 RAM. truck is mostly stock with a turbo back exhaust.

We're not going too crazy with the tune. max duration is around 2600us at 180mpa (stock fuel pressure tables). Timing may still be a bit conservative (around 52%) as this only got us about 92hp extra on my dyno (dynocom 5000 with about 45% load in 4th gear). I didnt want to venture too far off of stock.

the problem we're having here is in 2nd gear and sometimes 3rd on a WOT pull there will be random limiters kicking in. There isn't much of a pattern, i twill happen at different rpms and all the limiter tables are set to near max and it still does it. There is some slight oscilation in rail pressure commanded vs. actual but its not overshooting that bad, oscilation is maybe 5mpa at 160-180mpa.

I did have to add some duty to the base duty for fuel pressure table to get it to hold pressure so i'm not convinced his filtration system is 100%.

I'm going to have this guy change his filters but i'm just wondering if the TCM is somehow chiming in and making the ECM defuel? is there a way to log this? I tried selecting the only transmission pid group in the logger and it tells me they're not compatible :/

[30 RUM]

I assume this is an auto truck and the ECM is pull back to about 2400 or so? It could be a few things check F1179 and F1188 those will defiantly pull full back, also check your F0522 TQ Limiter Table you may need to fatten it up a bit. I do advise to be careful with adjusting these with a stock trans, it will slip very quick.:badidea:

Sam

[computerjlt]

Yes the truck is an Auto. Sorry I thought I said that in the first line. oops.

All of those tables are maxxed out already. The "studder/limiter" feels like spark blowout on a turbo gasoline engine but I know that isn't possible on a diesel. Plus I can see in the logs where fuel goes from a steady "155mm3" commanded to about 60-70mm3 commanded then goes right back up to 155 (which is max in the desired fuel @ tps table). So *SOMETHING* is telling the ecm to pull fuel for a few MS.

This truck is stock minus some "exhaust weight reduction" lol. I guess I'm going to turn it down a few hundred uS and see if anything changes. It wasn't complaining on the dyno but I also never ran it in 2nd/3rd.

It will blow the tires up in 1st if you smash it and it acts fine in the top of 3rd and 4th gear @ WOT and will hold full fuel. It doesn't feel like its slipping (though i'm sure a few percent you wont be able to feel but the TCM can definately see that) and I would think it would be more likely to slip in the higher gears.

I read in another thread about converting to a manual OS to ignore the torque management from the TCM but that scares me on this guys stock truck lol

[computerjlt]

The only "limiter" I still have active is B9904 and the D0511 is set to "Minimum" I was told by an early diesel tuning mentor of mine to never turn that off. He didnt really specify why when I asked so i'm not certain how or if this has anything to do with this.

I'm still fairly new to the diesel tuning world, so i'm trying to take small steps. I've been tuning turbo gas motors for over 10 years and these common rail diesels fascinate me so i've been trying to play more and more with them!

[2007 5.9]

09 autos all do this...needs the tcm to be tuned to solve the issue. There must have been a tcm logic change in 2009...all my 2007.5-2008 are perfect with no tcm tuning, but EVERY 2009 Auto has required the tcm to be tuned to remove the shift-de fueling.

[computerjlt]

But there's no way to mess with tcm settings with efi live yet correct?

[2007 5.9]

Correct, I use H&S to tune the tcm

[computerjlt]

well crap :(