[Joshinator99]

Originally Posted by carbon fibr

Hi all.
2021 Camaro ZL1, LT4 engine, Manual Trans. Mods: 2" Headers, Intake, Cat delete, DSX flex fuel Sensor.

Curious if anyone has come into issues with a failed High Pressure Fuel Pump (HPFP) after doing an E85 tune.
Got my car up to 55% Ethanol, did a few pulls and after the last pull my HPFP dropped right off to 50psi. Codes: P228C - Fuel Pressure Regulator Control Performance - Low Pressure, P0089 - Fuel Pressure Regulator Performance.
I was dialing in my last tune, verifying if my low-pressure fuel could supply up to 50-60% Ethanol. I didn't expect my HPFP to break; Curious if it could be related to my tune? I'm scared to run E85 now.
FYI: I just ordered a Fuel pump voltage booster & a new stock LT4 HPFP.

Any help greatly appreciated.
I can provide the log if anyone's interested in giving me a second opinion

If your low side drops off, it will then let the high side drop off. When the HPFP cannot keep up, it loses it big time! The rail pressure will simply fall off a cliff…. What was your low side holding at? What did your IPW look like? E55 seems like a lot for a stock fuel system LT4.