Losing fuel pressure. EKPM?

[Deleted member 2204]

Hi gents!

After 2 days of spirited autobahn driving with lots of 100 to 200km/h pulls, just as i was almost leaving the autobahn, i could no longer ask for any power.
With more than ~20% throttle, the car starts misfireing and if i don't back off quick enough, the car goes in limp mode.

I quickly got my odb cable and MHD app i started realtime logging. When i pressed the pedal, the lowpressure fuelsystem starts to lose pressure and the hpfp follows.
I then ran a log; https://datazap.me/u/ballistic/bmw-n54-335i-e91-autobahn-driving-no-fuel-pressure

I recently upgraded to a Walbro 450 lpfp but stuck with the EKPM3 thats in my car. At this moment i am blaming a fried EKPM so i already purchased a 2nd hand from Ebay.
I let the car cool for a few hours but the problem stays.

What do you guys think? Is this typical fried EKPM behaviour?


E91 N54 2010
MHD Stage2+ Flexfuel
Walbro 450 bucket (EKPM coded to avoid idrive fuelpump fault)
No ethanol in tank during the problem.

 

[135Pats]

When my EKPM went out low pressure fuel would rise to 80-90PSI under WOT (i'm guestimating that figure, it was several years ago), and wouldn't come back down into the 72PSI range until I restarted the car. It behaved normally under anything but full throttle. The car drove fine but it was an odd behavior that I wanted to fix ASAP; wonky fuel pressure isn't something to ignore. Replaced the module and all was well.

 

[Deleted member 2204]

Thanks for the input!
My hpfp is also crapping so the pressure really is dropping. Thats why i don't suspect the lowpressure sensor. So either the EKPM is fried or the new Walbro 450 already gave up. We will know soon!

 

[Deleted member 2204]

I hooked up ISTA to the car and let the fuelpump run in all 3 possible test modes. You hear the pump stable.
Issue is still there, even with cold EKMP. So i took another log;

datazap.me | Ballistic | BMW N54 335i E91 Autobahn driving - No fuel pressure

datazap.me

It shows decent low pressure. It's the hp rail that loses pressure as soon as i ask for fuel. Maybe the HPFP is a goner. As soon as shut off the car, the hp rail drops to ~70psi pretty much instantly. The lp stays at 72+ for a long time. I can't remember if this is normal or it should stay at 500psi+ for a while.
I have no long crank issues

 

[Jeffman]

It sounds like your HPFP is crapping out. I’ve never seen rail pressures below 900psi even idling. Good thing HPFPs are relatively cheap and easy to replace.

 

[PFS]

HPFP!

 

[Deleted member 2204]

Thanks, i think so too. I ordered 13517616446 yesterday at my local BMW dealer (i'm in the Netherlands) and got a call right away. "This part isnt for your car. It looks like a USA part. We can't guarantee it will fit and we have to get it from Germany. Maybe they don't accept the order" bla bla

They ordered it anyway and hopefully it will be here in a couple of days as this part nr only costs 400dollars. A new one costs almost 1000 dollars here.

fyi; a friend with same car verified; rail pressure dropping off quickly after shutting down car is normal.

 

[Jeffman]

Anyone in need of one of these HPFPs 13517616446 should order quickly. I just checked online and they seem to be out of stock on many sites. ECS / Turner still lists them for $509. The dealers who have them are charging $900+.

 

[Deleted member 2204]

Solved with a new 446 HPFP after all. Thanks for the input!

A new HPFP is very expensive even after the ~200bucks you get back for you old pump.