Frp

[killerbee]

Trying to bring new attention to an issue known years ago, but to the best of my knowledge, never resolved. This thread describes it.

http://www.duramaxdiesels.com/forum/showthread.php?t=69479

In short, FRP tables do not predictable alter FRP. Hopefully this stays on course.

[GMPX]

Well I will quote the post prior to yours....

"Sorry Mitch, but there was a work around I was told in private. If the guy wants it known publicly, he can post it here. I'm not going to share someone else's work though."

I'm willing to look in to it at some point but what I'd really appreciate is some hard facts....which OS's are ok, which are not. Is there one particular area of the tables that don't respond? Is it like this on stock trucks or only on very modified trucks.
It is hard for me to drop what I am doing to go back to a platform I haven't worked on for many years, half my day will be spent trying to remember how it all works so any information you can provide will be a big help.

Thanks,
Ross

[IdahoRob]

I may be able to shed some light on this Ross. Working on the fuel pressure tables on the standard LMM DSP5 OS 52628594. Comparing the base fuel pressure tables with the dsp pressure tables, the RPM scaling doesn't match. The LMM with that OS, any of the base and dsp fuel pressure tables, do not work for adding rail pressure at idle (600-1000rpm and 5-20mm3) This is really only needed when adjusting idle pressures for big injectors. I'm not sure if the scaling is correct for any of them and the reason the idle pressure is not affected. I brought these things up years ago but understand that things fall through the cracks, so figured out other ways to achieve the results needed.

[GMPX]

Working on the fuel pressure tables on the standard LMM DSP5 OS 52628594. Comparing the base fuel pressure tables with the dsp pressure tables, the RPM scaling doesn't match.
Ok, that might be a simple labelling issue, I can check that easy enough.


The LMM with that OS, any of the base and dsp fuel pressure tables, do not work for adding rail pressure at idle (600-1000rpm and 5-20mm3)
Which probably means at least for the LMM there is a specific idle mode RP table (I'm guessing).


I brought these things up years ago but understand that things fall through the cracks, so figured out other ways to achieve the results needed.
Yes unfortunately things do fall through cracks, lots of Emails always.

[killerbee]

Thank you Ross. My recollection from way back, is that I was not getting predictable "desired pressure" after significantly altering the main FRP table. On logs, the desired FRP did not match that predicted after zeroing the various compensation tables. I think I gave up back then after trying to surface the problem.

[GMPX]

Michael, I have a million projects on the go at the moment and it is very difficult to switch back to Bosch mode. I'm just saying this to convey that I am not about to drop everything to look at this, it'll be in the list of to do's somewhere.

[Monster50iii]

I pulled my hair out trying to get the correct desired frp. Once I figured it out, I laughed about it. Its not 'right', but isn't impossible to figure out. Just need to think outside the box a bit. It is predictable once you get it figured out. It does exactly what you want it to (outside of idle conditions).

Something else that isn't quite correct is the description on the timing correction values. In the description, it states that a value of '1' is equivalent to 1degree of change to main injection timing. This is true in areas other than the idle areas. Seems that a value of '1' equals .1deg of change in idle areas. Maybe there is something else in the background making the values less than what they should be.