I was comparing desired fuel rail pressure to actual rail pressure. took a freeze frame of a power lull problem.
1st run
170 ACT FRP (MMa)
177 DES FRP (MMa)
2nd run
172 ACT FRP (MMa)
179 DES FRP (MMa)

these are WOT runs and the freeze frames were taken during my power drop off in the 1-2 shift.
clueless to what these numbers mean

It means your actual fuel pressure is about 7 Mpa lower than commanded. It typically happens on high pulsewidth tunes near the shift (high rpm). Check the fuel pressure tutorial in my signature for ways to help it. Be sure you have the most recent updates from EFILive.com to access the necessary tables.

If the tune you're running is not a very high HP tune, there may be fuel filter issues or other diagnostics necessary. Need more info on the logged run to nail down the issue.


:)Nick

It means your actual fuel pressure is about 7 Mpa lower than commanded. It typically happens on high pulsewidth tunes near the shift (high rpm). Check the fuel pressure tutorial in my signature for ways to help it. Be sure you have the most recent updates from EFILive.com to access the necessary tables.

If the tune you're running is not a very high HP tune, there may be fuel filter issues or other diagnostics necessary. Need more info on the logged run to nail down the issue.


:)Nick

sorry didnt fully describe the issue in this thread...i was just using a scanner...i dont have efi live i just figured that you guys dealing w/these numbers would know how to read it, so thats why i posted here.

these are the other threads i have that is dealing w/ the problem and the purpose of using the scanner was to confirm that I need a lift pump for my higher tunes on the 6-gun. levels 6 and 7

The 1st and 3rd post in this thread explain everything that is going on.
http://www.dieselplace.com/forum/showthread.php?t=201815

the runs are being done in what is supposed to be roughly a 140hp extra Rwhp tune. The filter is new about 1000 miles on the filter.

That's not a bad drop at all. Looks like it's calling for about 25,500 PSI and it's getting about 24,500 PSI, so about a 1000 PSI drop. That's great for no lift pump. I don't think it's enough to cause your problem. If you really want to see if you need a lift pump, find a good place you can safely go faster than 70 and run it up through 4th gear at WOT. Where I normally see the biggest drop in rail pressure is at the top of 4th and 5th gear. It should be calling for 180 MPa. I like to see at least 170 MPa on all my tunes. I think it would be beneficial to keep yours there as well, but you can probably still do alright as long as it's above 160.

do the newer trucks run higher fuel pressures from the factory? My fuel pressure table for my LLY tops out at 160 MPa. LBZ and LMM trucks must come with a stronger CP3?

do the newer trucks run higher fuel pressures from the factory? My fuel pressure table for my LLY tops out at 160 MPa. LBZ and LMM trucks must come with a stronger CP3?Yes and yes.

well im not really concerned with my higher gears because it runs fine all the way to 100 mph. did a couple 1/4 miles.

What other values on the scanner should i look at to see what is going on when i get the power cut?

Torque reference or requested torque (could be named either) and main injection fuel quantity. If those drop you are defueling because of programming either in the TCM or the ECM/Banks module.

alright for the mean time i have solved my problem and the truck runs better than ever. I lowered fueling in first gear from 100% default to 65% and raised 2nd gear fuel to 80% from 60% default. This prevents fuel starvation in first and gives 2nd gear a little more power. I may even pull that number back a little because it almost pulls too hard and im afraid of tranny going boom. probably will put it around 70%-75%.