What kind of pressure are you seeing on your LPFP?

[FoMoCoSHO]

Just curious what others are seeing on their LPFP when logging or monitoring with one of the OBD programs.

I see 75psi to 85psi normal driving and 110@WOT.

 

[ajpturbo]

Sounds about right...although i dont think i remember anything over 100...been awhile since i looked at low pressure...it was just always consistent even when the high pressure dropped to 700 psi so i elominated it from my logs and stopped looking

What prompts your question?

 

[FoMoCoSHO]

It seems like some cars seem to hold pressure better than other and am curious what the differences could be.

Gen 4.1 cars have a different pump as well so I'd like to see what they hit.

 

[ajpturbo]

So I'm looking at an older log of mine. At about 200kpa or 15 psi during a 3rd gear sweep from 2k to redline I am commanding between 80-90 psi and actual low pressure fuel matches that. Fomo, I don't think you are getting 110 psi because you are commanding that but rather because when you are WOT and then lift, the throttle closes and there is no longer a high demand for fuel and the system dead heads. No where for the pressure to go and it spikes.....My log show low pressure fuel at about 108 when I lift at the end of the WOT

Also on WOT upshifts, right at the shift when the RPM's are falling it looks like there will be a brief pressure spike in the low fuel pressure...Must be because the HPFP is not eating the incoming fuel from the low pressure lines because engine RPM's are falling