Losing fuel pressure. EKPM?

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Deleted member 2204

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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

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Nov 17, 2016
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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.
 
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Deleted member 2204

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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!
 
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Deleted member 2204

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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;

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

Major
Jan 7, 2017
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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.
 
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Deleted member 2204

Guest
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

Major
Jan 7, 2017
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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+.
 
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