[TrueNutty1]

Fellow PWGer here... So, I just flashed to MHD E30 Stage 2+ today and did a couple of pulls. I was not scientific in my mixture and put 4gal of Shell E85 and the rest 91oct. I log quite a bit and have never had my rail pressure deviate from requested until today. It crashed 750psi at 4k until returning to normal for the rest of the pull. I know I need to be accurate with the E85 if I intend to continue to use this map but my question is if my HPFP can even handle it? Does the crash mean my HPFP is on it's way out? I've used 3gal of E85 before on stage 1 93oct without issue. Not sure how worried to be. Car has 73k miles. No codes have been thrown and I've never had one related to fuel pressure.

The first pull:
https://datazap.me/u/truenutty1/4th-...&data=17-18-19
The second pull (with crash):
https://datazap.me/u/truenutty1/4th-...&data=17-18-19

[thejeremyman9]

I looked at the log with the crash. The dip isnt totally catastrophic, but if it happens consistently, i would dial back the ethanol content. Maybe try 3.5 gallons instead of 4. The timing was super clean so you can probably get away with less. It looks like the DME closed throttle as a result of the HPFP dip, so that's a sign that the DME thought the dip was "too much".

A couple other things:

- Boost is quite high actually... a little surprised you are targeted 17psi in the beginning, but that could be because of the relatively high ambient temps and it seems like you are a bit of altitude.
- You are missing manifold boost from your logged parameters.
- STFT are quite high (negative high), and you are pulling more than 10% fuel throughout the pull. Thats surprising because if your ethanol content was higher than what the tune expected, it would be adding fuel (positive STFT).

Finally, i would note that you will definitely crash the HPFP if ambient temps/IATs are higher. You are at 90F and the fuel demand will only increase with colder temps (although boost should be lowered somewhat at the same time - the benefits of a load based tune).

The HPFP is mechanical so it is very unlikely it is "on its way out".

[TrueNutty1]

Originally Posted by thejeremyman9

I looked at the log with the crash. The dip isnt totally catastrophic, but if it happens consistently, i would dial back the ethanol content. Maybe try 3.5 gallons instead of 4. The timing was super clean so you can probably get away with less. It looks like the DME closed throttle as a result of the HPFP dip, so that's a sign that the DME thought the dip was "too much".

A couple other things:

- Boost is quite high actually... a little surprised you are targeted 17psi in the beginning, but that could be because of the relatively high ambient temps and it seems like you are a bit of altitude.
- You are missing manifold boost from your logged parameters.
- STFT are quite high (negative high), and you are pulling more than 10% fuel throughout the pull. Thats surprising because if your ethanol content was higher than what the tune expected, it would be adding fuel (positive STFT).

Finally, i would note that you will definitely crash the HPFP if ambient temps/IATs are higher. You are at 90F and the fuel demand will only increase with colder temps (although boost should be lowered somewhat at the same time - the benefits of a load based tune).

The HPFP is mechanical so it is very unlikely it is "on its way out".

Thanks for the advice. I've been weary of my fuel trims as I'm usually kinda rich. It is common for me to see up to -10 STFT at WOT on any tune except stock where it starts at a higher positive and ends on a higher negative. Need to check my injectors and clean my MAF. But I'm glad to know I can back off the ethanol and should be fine. I'll try that.