Ms6 fuel rail pressure loss past 5000rpm

[Rogi]

If your pulling the itfp you should change the filter sock too

Filter sock was replaced with a 3x15” hydramat

 

[Enki]

Well that *should* be enough flow. Lol

 

[Rogi]

Well that *should* be enough flow. Lol

yes it should haha, was more expensive than the fuel pump itself so it better. thinking about it now it’s going to be a pita to remove it with the basket and reinstall if it ends up being the fuel pump.

 

[Enki]

You just put a new pump in though right?

 

[Rogi]

You just put a new pump in though right?

No, just new hydramat. The in tank Fuel pump has some miles on it from another project. The hpfp internals are the ones that I just installed a new set in.

 

[Rogi]

update- i got an amazon special hpfp for research purposes that came in today, did not touch anything except the retaining nut/seal screw for the piston, swapped that out with my old autotech internals ( the one that has slight discoloration, uploaded pictures in this thread on page 1) primed the pump with redline and installed it. here are 5 data logs, consistently better fuel pressure all the way up but it does dip below 1600psi here and there, but not as crazy as previous datalogs. now for the 1500psi dips im thinking it could be the old autotech internals or be it that its not an oem hpfp or even both. am going to put the new autotech internals in just to see if itll make a diference. Did not get a chance to install a mechanical gauge on my fuel pressure regulator, but will hopefully tomorrow just to rule that out aswell. this is pointing more towards that the other two hpfp are defective or i have screwed something up when rebuilding them.

 

[Rogi]

update- swapped out the internals for my new set of autotech internals in the amazon hpfp, this time i swapped out the internals with the retaining nut/seal screw from one of my oem pumps, didnt touch anything else. took some data logs and it looks like the fuel pressure loss at high rpms is back. here are some logs. am going to take the pump off one more time and swap the internals into the retaining nut that the amazon hpfp came with just to confirm before purchasing an oem pump. also i hooked up a mechanical gauge to my fuel pressure regulator, it rose to 55ish psi and stayed there until i let off. @Enki have you ever seen or encountered a faulty retaining nut? i know it seems odd but based on logs this is what its pointing at. maybe i could have damaged the retaining nut or deformed it by overtightening it.

 

[Enki]

Can't say I have. Maybe pull the X ring out of it and see how the internals cycle within the nut; should be smooth and easy.

 

[Rogi]

Can't say I have. Maybe pull the X ring out of it and see how the internals cycle within the nut; should be smooth and easy.

will do, ill report back tomorrow and hopefully finally have this headache resolved.