EKPM Saga - JB4tech.com

FastForAnN55 · **EKPM Saga -** 03-02-2022, 02:58 PM

Hi all
So I have been having an issue that seemed like a problem with the EKPM. Car starts and idles for a few minutes then, first throws EKPM voltage too low and current too high (6292, 6293), then within another minute, it goes into limp, then dies. I don't even have to drive it for this to happen.
I replaced (and reprogrammed) the EKPM. Exact same issue is still happening.
Using a scan tool, I watched the voltage, current and flow rates at the lpfp and hpfp.
The voltage at the pump does seem low at ~10.5v. The pressure at the lpfp remained at 87, never fluctuated. The pressure at the hpfp starts at ~7.5 and drops quickly as soon as the first code is thrown.
Given this, it seems like a bad hpfp. I've done some reading and it seems like there are other plausible items, e.g. fuel low pressure sensor.
Thoughts?
Thanks
Car:'11 E90, Pure stg2, BEF, port-inj, all the bolt ons

RVA_N55_Fan · 03-02-2022, 05:18 PM

Have you upgraded hpfp or lpfp?

FastForAnN55 · 03-02-2022, 05:25 PM

Fuel-It Sgt2 bucketless

RVA_N55_Fan · 03-02-2022, 09:21 PM

How long after you put the lpfp in did the issue begin?

FastForAnN55 · 03-03-2022, 07:39 AM

lpfp had been in for a couple years. Car has been in current config for a couple years. Car has been parked with this issue for several months. And just to be sure the lpfp was the first thing I replaced after this issue started. (I forgot to mention that. Also has a new battery.)
So to me it seems like it's either something else electrical/some sensor or the hpfp. But I am open to other ideas.

Steve @ BMS/Fuel-It! · 03-03-2022, 11:48 AM

LPFP "pressure" is a false reading as there is no LPFP sensor on the N55. The LPFP is also PWM controlled so the voltage will read lower at idle and cruise.

FastForAnN55 · 03-03-2022, 12:17 PM

Thanks Steve. Good to know.
So the only thing left is the drop in pressure at the hpfp... unless I got 2 bad EKPMs... seems doubtful. Maybe years of ethanol just fried the hpfp?

RVA_N55_Fan · 03-04-2022, 01:11 AM

Still have OEM lpfp? I'm no expert but may be worth reinstalling for troubleshooting. Hpfp is pricey to not troubleshoot all other variables.

Steve @ BMS/Fuel-It! · 03-04-2022, 11:43 AM

E85 won't have any affect on the HPFP.

FastForAnN55 · 03:48 PM

Today I replaced the hpfp. Problem still exists. I did note that as I was sitting there letting idle that just before the car dies, I could here the LPFP shut off. Is there something electrical down there with the LPFP that could be failing?
Just to review: New battery, new LPFP, new HPFP and "new" ekpm (not brand new but an ebay replacement).
Also, FWIW, after the car died, I felt the EKPM and it was just warm, not hot.

RVA_N55_Fan · 03-06-2022, 04:01 PM

Yes lpfp has power connection. If any are loose, then it will shut off.

FastForAnN55 · 03-06-2022, 04:06 PM

Yes, I checked the connections, they are good. Wiring looks good too.

RVA_N55_Fan · 03-06-2022, 04:16 PM

Fwiw I've read somewhere these but I'm not certain: the pump may have been impacted if there was an issue via ekpm issue. Longshot but there may be a fuse in the trunk (though I'd think it wouldn't cut in at all if this was the issue)

FastForAnN55 · 05:30 PM

I took the cover off the ekpm and used laser thermometer to check temps of components while the car was idling. I mainly kept an eye on the 3 items circled in the attached pic. At no point, even when the LPFP shutdown, did anything get over 175F. I don't know what a normal operating temp range is for these ICs but that doesn't seem excessively hot.

RVA_N55_Fan · 03-06-2022, 05:32 PM

Will need others to offer thoughts or replace the lpfp pump itself...Walbro 450/525/535?

FastForAnN55 · 03-06-2022, 05:36 PM

It has a new Fuel-It stage 2 bucketless

FastForAnN55 · 03-11-2022, 09:54 AM

Update: I bought a new OEM BMW EKPM. That seems to have fixed it.
The lesson, for me anyway, is don't buy used electronics off of evil-bay ;-)

RVA_N55_Fan · 03-11-2022, 08:05 PM

Nice work man.