First 6.7 Tune, looking for advice.

[2007 5.9]

You may put those tables back to stock, and log actual vs desired rail (not DC) and I bet you don't have much issue hitting target rail.

Simply making the assumption that based on visuals that rail is limited without logging, may be causing you unnecessary tune changes and issue.

[computerjlt]

thats where i first noticed the problem was in rail pressure... let me find some logs

actual vs. desired rail pressure wasn't hitting thats when i noticed duty cycle. made some small changes and now it hits.

it could be coinincidence that all the trucks have factor lift pumps and old filters. you're probably used to trucks with nice lift pumps and or new filters

[computerjlt]

here are screen shots from the last truck i did. 07.5 6.7 stock fuel system with intake turbo back and deletes.

the initial run was pretty short but it still didnt hit rail pressure. the next run was longer but almost instantly hit desired rail pressure and held pretty well. the only change i made was adding about 20% to the base duty table. I didnt touch the max duty like i thought i had.

[2007 5.9]

Well to be fair in the first screenshot you were commanding 180MPa and the in the second you were commanding 167MPa...that alone will provide a better chance of achieving target rail when your running a 2800uS pulse on a stock fuel system.

[computerjlt]

this is true. but even then it never hit it in the first log.

i'll do more testing the next time i have a 6.7 on the rollers and see what happens