[N55lif3]

I keep having my rail pressure crash on me during WOT on an E30 ps2 tune.

My high-pressure is brand new. I just got my LPFP upgraded to a warlboro 450 (just pump) thinking it was just the LPFP but it changed absolutely nothing. The rail pressure still crashes the exact same way as it did before and every now and then my car stalls on cold starts (like before aswell)

I have some people telling me it could be my EKP but I get absolutely no codes in regards to it.

On my E30 tune the car violently backfires/sputters during peak boost cutting out power and then continuing. The weird part is that the next day the car can be running perfectly fine on back-to-back WOT with no timing corrections.

On my regular daily driving map which is set at 11psi, the rail pressure spikes up and down on WOT. Jumps from 2900 to 2100 to 2900 to 2100 etc and slowly steadies.

[cookiemontis]

Is your hpfp the older rotary style pump?

I had phantom stalls due to the ekp overheating after upgrading to a walpro 450lph pump, would coast to the side of the road, wait 5 minutes and start and run fine. Then it might do it again the next day or 4 days later. Was very intermittent, and only happened after 2 years of use, so the normal shadow codes I got since day one of the install were dismissed.

I ended up buying a used one on eBay, then purchased a 3/8 aluminum plate to put between it and the mounting plate to help disapate heat. Never had the issue again.

So it is something to look at, since you recently replaced both pumps and your car is still exhibiting the same behavior.

[xxMike61]

my 2 cents. Had a similar problem after upgrading my lpfp to stage 2. ended up swapping the fuel pressure regulator and hpfp and everything turned out fine. I have a couple logs for you to look at.

I was also experiencing the same cut off/ backfire during full boost. Mainly happened when i was on the mhd stage 2+ tune and not at all with the 1+ tune. Everything is fine now even running the mhd e50 tune.

Prior to all of this I was having the 0bde? fuel shadow code for at least a year. In hindsight I think the fuel pressure regulator was fine but I kept it in because it was a pain to get to

https://datazap.me/u/xxmidnite/fuel-...-16&solo=10-15

[jlegelis]

N55lif3 for the later N55 cars, you need an upgraded / higher capacity HPFP, either XDI or Dorch. With a PS2, the LPFP is not the problem. Can you post a log? Here's mine before the XDI upgrade: https://datazap.me/u/jlegelis/wedge-...&solo=11-12-24 , and after: https://datazap.me/u/jlegelis/v12-xd...&solo=11-12-24

Wish I had better news, but for 'late' E9x N55 the stock HPFP is a serious barrier to bigger power.

[N55lif3]

I dont have the late HPFP. I have the early N54 pump. And I've changed it twice now just because of the sputtering and its still doing it with only E30 blend. Keep in mind that one day it'll do it and the next it wont (with the same IAT and MAF g/s)

Warlboro 450 LPFP upgrade did nothing aswell.

I'm also having some stalling issues on cold starts every now and then.

I got a shadow code in regards to fuel pressure right after one of the cold start stalls even with the new hpfp. The car starts right away, it just begins to stall and die out unless I give it steady gas for 5-10 seconds and it'll be fine again.

I found a video that perfectly describes it:

[N55lif3]

Originally Posted by cookiemontis

Is your hpfp the older rotary style pump?

I had phantom stalls due to the ekp overheating after upgrading to a walpro 450lph pump, would coast to the side of the road, wait 5 minutes and start and run fine. Then it might do it again the next day or 4 days later. Was very intermittent, and only happened after 2 years of use, so the normal shadow codes I got since day one of the install were dismissed.

I ended up buying a used one on eBay, then purchased a 3/8 aluminum plate to put between it and the mounting plate to help disapate heat. Never had the issue again.

So it is something to look at, since you recently replaced both pumps and your car is still exhibiting the same behavior.

Unfortunately the car doesn't stall when its warm. It only does it right when its cold every now and then. I think overheating EKP would mean that it would occur after driving the car for a while.

[cookiemontis]

Do you have the newer style or older style hpfp. Do you have any logs of the issue occuring?

[N55lif3]

Originally Posted by cookiemontis

Do you have the newer style or older style hpfp. Do you have any logs of the issue occuring?

Older Style HPFP.

Misfire/sputtering on e30 log:
https://datazap.me/u/n55rei/misfire-e30?log=0&data=4-13

Rail Pressure odd behaviour on 12psi map:
https://datazap.me/u/n55rei/log-1615...og=0&data=4-13

[jlegelis]

What are you seeing for codes?

[anjuna]

e30 log - Is nobody going to address the fact that the car is running so GD rich that the lambda sensor is crashing into "this is so fucking rich that I cannot read any richer?"

12psi log - Yeah, your tuner is calling for crazy fucking high HPFP pressures. I've seen this before. The fuel mass per injection to pressure ratio is stupid. You should not need that sort of pressure for that level of power. For reference, I run 2350psi at WOT and I run 21psi. I have a 2011, so yes, old style pump.

You need to contact your tuner and educate them on the pressure vs consumption curve. When you don't have crazy high fuel consumption, you don't require such high pressure. With these types of pumps, it is true that volume can be increased by pressure, which leads people to believe that they MUST have high pressure to meet their fueling "requirements" for their power.

HOWEVER, by cranking the HPFP to over9000, the tuner is effectively changing the spray duration and window for the injector for it to meet the same fuel mass. Yes, it will take a longer spray time at a lower pressure, but the spray window is met. Unless they changed injection timing, which I HEAVILY doubt.

When the HPFP is set to very very very high PSI, the injectors are essentially spraying the entire fuel mass at the very earliest part of the injection window, which makes performance shit. This is almost as detrimental as retarding ignition timing a large amount. Every event in the "bang" cycle must be timed correctly (valvetronic, VANOS intake, injection timing, injection duration, ignition timing, ignition dwell, VANOS exhaust, etc.)

[N55lif3]

Just want to let anyone who was interested know that it was in fact my EKP module crashing. I upgraded to an EOS.

I was getting stalls on cold starts and sputtering on certain days at WOT. I got an EKP code one day and finally realized that it couldn't handle the current of the LPFP.

Thanks

[Ode2logo]

Originally Posted by N55lif3

Older Style HPFP.


Rail Pressure odd behaviour on 12psi map:
https://datazap.me/u/n55rei/log-1615...og=0&data=4-13

N55lif3

Did you fix these HPFP spikes ? I get the same issue. tryed to reduce the fuel pressure ( fuel pressure target table) but it didn't change anything. Don't know what to do at this time

Single barrel VTTO
Walbro 295

https://datazap.me/u/ode2logo/fuel-t...1&data=3-21-22

Thanks

[N55lif3]

Originally Posted by Ode2logo

N55lif3

Did you fix these HPFP spikes ? I get the same issue. tryed to reduce the fuel pressure ( fuel pressure target table) but it didn't change anything. Don't know what to do at this time

Single barrel VTTO
Walbro 295

https://datazap.me/u/ode2logo/fuel-t...1&data=3-21-22

Thanks

EKP Module! Replaced with used one and ordered EOS