I've got a 2005 Cummins with 12mm cp3 and 100% injectors both from s&s stock fca being fed by a fass 290. also has stock turbo and a fmvb where i turned 'auto trans off' in the tune file. I'm having trouble dialing in my fca part of my tune where my frp will surge from 14kpsi to 17kpsi when I am accelerating between 1300-2100rpm. This is especially with my torque converter unlocked.
I need to resolve this issue as it will sometimes surge so bad that it starts accelerating even when I let off the accelerator. Gets pretty sketchy when there's snow on the road and am in traffic.
I've got a log file and the tune file attached so you can see whats going on. if needed i can add a video of what it sounds like.
any help really appreciated as this issue has been getting on my nerves
in all honestly, fix that insane timing you have going on and fix the pulsewidth table. if you are using a timing calculator to set your timing table, get rid of the timing calculator. you are dumping large amounts of fuel in super early with what you got going on in this. you have oversized injectors and you crank up majority of the pulsewidth table even more. the issues lie in the time tables, pulsewidth table and rail pressure tables.
Last edited by Jim P 2.0; 2 Weeks Ago at 12:23 AM.
Highly suggest putting everything and I mean everything back to stock except for the necessary changes for the fmvb before you find yourself picking up connecting rods or something up off the street.
would you have any other suggestions for op? I have similar mods and my log looks similar to his. desired vs actual fluctuates anywhere from 200-800psi. only happens when desired is steady like on cruise control. started after cp3 was installed. thank you
Fluctuations are normal, actual will not follow desired right down to the decimal point. A difference as low as 200psi isn’t even something to think about to be honest. It’s a rotary piston pump, it inherently has fluctuations and when you start factoring in latency time for electro to mechanical response, sudden increase or decrease in fuel demand and the time to respond to those changes, there will always be some fluctuations. And that log above, only one spot I see in it that showed abnormal rail pressure fluctuation and believe me no amount of FCA adjustments will fix that. That entire tune is an absolute mess.
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