Is my HPFP failing? (Logs + Video)

[G82 Jesse]

I was at the drag strip tonight, and something new happened with my car that I haven't seen or experienced before. There was this bizarre stuttering sensation past ~5500 rpms, as if I'm bouncing off an endless amount of hidden rev limiters. You can hear it in the video, especially in 3rd gear.

The issue actually got substantially worse throughout the night (Genius move, continuing to do runs after hearing that.... I know..). I thought my E50 blend maybe wasn't mixed well and I'm suffering from knock, so I flashed a 91 tune and went home.

On-ramp on the highway, I tried to get into the gas a bit, and was shocked when this stutter still happened. I grabbed a quick log, and it appears that my 'HPFP target' vs 'HPFP actual' are wildly off.

Is my engine simply starving for gasoline? This issue is brand new as of tonight. I've been running this tune just fine for a bit with zero issues until now.

If the high pressure fuel pump is indeed the culprit, what am I looking at for upgrades? Cost, anyone else who has done it, etc? Thanks very much.

LOGS OF IT HAPPENING: https://www.bootmod3.net/log?id=6190...729b0b5ed8345b

[TopJimmy]

Please log again including the LPFP, not a hard run, and stop soon as you catch the stutter. You are correct that the HPFP Actual is dropping far from the Target but it's not clear if the LPFP is falling short on supply or if the HPFPs have a problem.

Also need real good details of what you're running...mods, tune, etc.

[G82 Jesse]

Got it, I'll get that done ASAP. For now, my mods are:

Pure Stage 2+ Turbos
CTS Turbos Intakes
Catless Down Pipes
Upgraded Charge Pipes
E50 Custom Tune through Paul Johnson
Stock fueling system

[TopJimmy]

If it's a Paul Custom E tune you probably forgot to set HPFPs to Original (not OEM). Double check that.

[G82 Jesse]

Oh, yeah I am INDEED on 'OEM' and not 'Original'. By the way, with logging, how to I log the low pressure fuel pump? Is that under the advanced settings? The only option I see in the Datalog Config is 'Other Channels' -> LPFP Act. (Raw), and LPFP Sensor Voltage.

[TopJimmy]

That's it. Having HPFPs set to OEM instead of Original does that with a Custom tune. I didn't know when I got my first rev from Paul and the same thing happened. Setting to OEM will pressure HPFPs for a gas tune, since there are no OEM alcohol tunes.

Yes, LPFP is now under Other Channels. Get both WGDC 1 & 2 from that list too, skip WGDC 1 on Default Channels.

[G82 Jesse]

Originally Posted by TopJimmy

That's it. Having HPFPs set to OEM instead of Original does that with a Custom tune. I didn't know when I got my first rev from Paul and the same thing happened. Setting to OEM will pressure HPFPs for a gas tune, since there are no OEM alcohol tunes.

Yes, LPFP is now under Other Channels. Get both WGDC 1 & 2 from that list too, skip WGDC 1 on Default Channels.

TopJimmy You probably just saved me $3500 on a Spool fuel kit, or at least a fair amount of headache. When swapping burble settings at the gas station the other day, somehow I went to "oem" on the HPFP settings. This is the first time I got a revision from Paul, the base supplied map was fine all week when I had a chance to run it and data log. I changed it to "original" and flashed tonight and the car is running like a dream all the way to redline!

Seriously, such a simple tip made all the difference. Thank you!! Too bad I didn't have the correct settings running at the drag strip, maybe I could've broken into the 10s for the first time

[TopJimmy]

Happy to share the love


Now you can

[Wanted_M]

You owe Jimmy a beer