Df20 running extremely rough

[lorenz19841]

Hello, anyone has an idea why the motor is behaving like this? Fuel pressure looks good and injectors seem to be clean.
looks like under load is worse than trying it out of the water, any idea?
https://youtu.be/m08MzD8O2iI

[Hoosmatroos]

Sounds like it's not getting fuel enough. The first thing you can do is check the complete fuel system from tank to motor. Change filters and check for leaks. Also check the high pressure fuel filter.

[lorenz19841]

I will try check that again but not sure it's something on the fuel line..

[Hoosmatroos]

Filters, specially the high pressure filter in the VST can be the culprit.

[lorenz19841]

I will change the low pressure fuel filter and remove the hp one (I cannot find where to buy a new one.. any idea?)
do you think it could have anything to do with the fuel pump malfunctioning?
for some reason after running the motor for a while it gets worse..
this motor had an issue with water in fuel but after that I fixed it and it was running perfectly for 2 trips and later it started having this issue.
one of the things I did when I fixed it was to take apart the hp fuel pump and completely clean it from water, and any small sign of oxidation, I also reopened the pump after the motor started showing this issue and all looked fine to me, small pistons where moving smooth and not getting stuck.

[artdf175]

sounds like the fuel problem may have returned
do you have a fuel/water filter installed?
drain the fuel from the high pressure fuel pump and see what you find
Art

[lorenz19841]

hello,
it's been a while since I couldn't test the motor, what I did to try fix it is replace the EFI fuel pump and replace the fuel filter but it didn't work. finally found out that the motor was running on 1 cylinder because one of the plugs was not working well. the replacement seemed to have fixed the problem, the motor was running well, just missing something sometimes while idling in neutral but that was it. after testing it for over 5 hours with no problem the motor started having a strange issue, basically 2/3 of the throttle where not responding, while I was turning the throttle the rpm where not increasing, motor is basically passing from idling to full speed, all the throttle positions in between are not responding.
do you have any suggestions? I already checked the throttle cable and that's not the issue.