Technical Possible High Flow Fuel Pressure Issue

RabbitOLychee

Private
May 23, 2022
36
2
0
Hey Team

I have another thread showing some images of my injectors out of my E90 335i (I had thought they were going faulty) but in my troubleshooting efforts I have noticed something a bit peculiar with the high flow fuel pressure reading on my data logs.

I notice everyone seems to get around 2800-3000PSI fuel line pressure even at around 12psi but I have noticed on my logs (which I posted on the other thread) that I am getting around 1900-2000 MAX PSI even at 16psi boost at WOT, this seems about 1000PSI lower than many of the other logs I have looked at today from other people.

Just wondering if anyone thinks this could be the source of my issue, is it possible my perceived injector problem is really a High Flow fuel pressure issue.

NOTE: I have put 3 rounds of Liquid Moly injector cleaner through it over the last couple of weeks to try and solve my issue.

Here is my log for anyone that wants to have a look:

Thanks in advance :)
 

RabbitOLychee

Private
May 23, 2022
36
2
0
Yes, HPFP is falling short or target. Time to replace it.
Hey NoGuru,

Thanks for sharing that, I'll replace that very soon!
By any chance, because the HPFP is failing, does that cause bank 1 injectors to go bad or is that another whole problem? Because my bank 1 injectors are full of carbon and bank 2 injectors look great..

Should I replace HPFP and Injectors or just HPFP? Only reason why I say that is because I got super knock code on cylinder 3 and combustion misfire on cylinder 1 on MHD.

Reason for that is because way previously I had a blocked cat in bank 1 and I ran it like that for ages thinking it was fine but it caused lots of carbon on everything..

Cheers mate, highly appreciate you coming back to me 😁
 

NoGuru

Captain
Jan 9, 2018
1,177
556
0
Just North of Detroit
Ride
BMW 335is
I would just replace the HPFP for now and see if that resolves the issue. The HPFP is over $1000 and same for injectors so just do one thing at a time. The injectors might clean up over time.
 

Griff500

New Member
Sep 29, 2020
2
1
0
For my learning, how are you diagnosing a faulty HPFP here NoGuru?

I see the LPFP struggling and lots of throttle closure events but I can’t see what you’re seeing with regard to HPFP not meeting target. Rail pressure isn’t dropping below 1700psi when under load - I thought this was ok?

Guidance appreciated
 
  • Like
Reactions: turbohugh

RabbitOLychee

Private
May 23, 2022
36
2
0
I would just replace the HPFP for now and see if that resolves the issue. The HPFP is over $1000 and same for injectors so just do one thing at a time. The injectors might clean up over time.
Alright sounds like a plan.. Having bad injectors being the worst thing, it won't damage the new HPFP?
 

NoGuru

Captain
Jan 9, 2018
1,177
556
0
Just North of Detroit
Ride
BMW 335is
For my learning, how are you diagnosing a faulty HPFP here NoGuru?

I see the LPFP struggling and lots of throttle closure events but I can’t see what you’re seeing with regard to HPFP not meeting target. Rail pressure isn’t dropping below 1700psi when under load - I thought this was ok?

Guidance appreciated
No, you are right, LPFP is not keeping up. I should have noticed that. I would start by replacing that. Upgrade it if you can.

Sorry @RabbitOLychee , I should have caught that. Replace the LPFP first and see what happens.
 
  • Like
Reactions: turbohugh