FCA tuning.

I have a 06 5.9 swapped into an Excursion. My dad gave me the motor. Long story short it has a Modified pump from Floor it. Other than the pump it is basically stock. The fuel pressure was fluctuating to a point where it was barely tolerable to drive at cruising speeds because of the surge. I tweaked the MA table and it is much better now but the pressure still seems like it fluctuates a lot. I am not sure if I should keep trying to fine tune the MA table or if I need to try tuning the PID parameters.

Attachment 23432

Looks like the FCA is running pretty close to the bottom end of its percentage range. If it was me I would increase the mA in the 1-10% range to try get the loop to run at a higher percentage and hopefully get it closer to a stable system or I would get a stock FCA and try that.

I would agree with Arin. However the data log has a lot of info that is missing like CMD and other helpful items.

i would suggest a new data log with more details.

Quote:

---

Originally Posted by tylerltr450

I would agree with Arin. However the data log has a lot of info that is missing like CMD and other helpful items.

i would suggest a new data log with more details.

---

Agreed, always grab EDA if you have room.

Do you know how oversized the pump is?

Sent from my SM-G935V using Tapatalk

I haven't done a whole lot with EFI so still learning. If I select the EDA1 entire group and CMDFUEL from the fuel balance rates, should that do it?.

Not sure on the size. I think my dad had told me that it was 30% but that was way back when. When I first put the engine in the FCA was sticking. I had a stock one in it for quite a while cause I didn't realize that the FCA was modded too. It's been a while but I'm pretty sure that it was the throttle hang that was the problem with the stock FCA. I took the floorit FCA apart and got it loosened up and put it back in.

I'll do a new log with the current setup and I'll see if I can get any better results adding MA in the 1-10% range and log that too

Thanks for the input!

It's been a long time but I finally got around to messing with this. I did What was suggested and seems to have taken care of the surging under most normal driving conditions so far (see log 0123). What I have noticed is that there is a noticeable lag at throttle tip in. It looks like rail pressure is dropping right at tip in and takes a little to recover. I am also noticing that when it goes to 0% throttle rail pressure drops then starts to slowly increase. (log 0123). At lower speed medium load it seems to have some of the "surge" type behavior. Is this a PID tuning issue at this point or could there still be some improvements made with the MA map?

Thanks for the help, I'm not sure how long it would have taken me to get this far. The MA map seems so counter intuitive to me.

I should also mention that I have a low stall torque converter so the pressure drop at tip in is probably exaggerated by the fact that the tighter torque converter doesn't allow as much rpm increase right off idle but it seems to happen even at cruising speeds

Again, it's been a while. I had made some good progress but got to a point where i couldn't really get much more improvement. Back in the beginning my FCA had been gummed up so I had it apart to clean. I decided to pull it out and check the retainer depth. It looked like it might be a little far in. I reset the depth with a depth mic to .025. On my first round of tweaking the map from stock I am already closer that I was before. Here's to hoping