Did a carbon cleaning after 70k miles and there was a limited amount of buildup, really no big deal. I also replaced all four injectors and the HPFP. Unfortunately, that didn’t cure the rail drop issue.
This log was taken with the brand new parts installed and you’ll see that rail pressure drops 900 psi below the set-point and there is some knock only on Cyl 1. I’ve boroscoped the cylinder… while the amount of knock on Cyl 1 in the log isn’t particularly high, it’s clear that it’s lean as there are signs of detonation on top of the piston.
It stands to reason that Cyl 1, furthest away from the HPFP down the rail, is not getting enough fuel when the rail pressure drops. This only happens at WOT, there are no issues driving normally and there are no other drivability issues. I’ve also never gotten a code for rail pressure too low, which is kind of puzzling, but it’s definitely not following the set point.
Process of elimination here… the Injectors and HPFP are new, known good parts. I’m prepared to replaced the LPFP next. Am I leaving out any other possible cause?
I’m curious as to where others on pump gas tunes, particularly from EQT, see their LPFP duty cycle % at WOT. Mine sits at 92%, which from my understanding is maxed out.
@Diggs24 , what would you say is a safe LPFP duty % range for a pump gas is38 tune?
, what made you get your oil tested?
