[graylens]

Hello everyone, I'm having issues with my 2008 BMW 335i E93 N54-engine that is testing the limits of my patience:

On April 6, 2020 at 92562 miles, I was getting problem codes P2B2C (High Pressure Fuel, plausibility, cold start) and P29F2 (High Pressure Fuel System, Fuel Pressure). Looked up on forums here & elsewhere, looked like it was the High Pressure Fuel Pump (HPFP). I replaced it with an OSIAS fuel pump from Amazon with a 3-year warranty here: https://www.amazon.com/gp/product/B07K7G9R35. Before I get the inevitable "you should have gone with the BMW OEM" comments, they're not helpful right now, and I can get a free replacement if this is still the fail part.

The following is provided as background just in case it could be related -- At 94176 miles on July 15th, she threw codes P0306, P0303, and P0300, but was able to limp home. These are misfires in cylinders 6 and 3. Ordered replacement coil packs and spark plugs from FCP Euro, and found out my standard spark plug removal plug was not thin enough. While I was waiting for the socket to arrive, I just replaced the coil packs and the issue/codes went away. Replaced the spark plugs anyways when my ATLIN Thin Wall Spark Plug Socket 12pt/14mm arrived with Bosch ZGR6STE2 plugs. Car ran buttery smooth until...

The following is provided as background just in case it could be related -- At 94407 miles on August 10th, I noticed a small coolant leak near the upper radiator hose. Yes, it was the classic crack at the upper radiator hose plastic connection. I tried JB Weld first, but ended up replacing the radiator. Really enjoyed doing that in the 114 F days Phoenix was going through at the time!

Just when I thought I was out of the swamp, I'm out enjoying the car at 95005 miles after the substantial work I've put into it, and it throws codes P142E (Low Fuel Pressure in High Pressure system, cylinder cut-out) and P302C (High Pressure Fuel System, Pressure falls below minimum threshold), and I get the reduced power/half engine light. No long cranks at start for awhile, but beginning to get them now. If I let it cool down and clear the code, she will run fine until I'm at full operating temperature and going up an incline, such as a freeway exit, then she'll throw one of those two codes. After throwing the code the car does not run extremely rough like it did when the HPFP went out in April, but it's definitely not it's normal accelerating self.

It's been less than 2500 miles since replacing the HPFP, did I miss an underlying problem? Why does the car need to be warm to cause the HPFP problem? Someone please help me before I swear off BMW's forever...

[BSM n54iS]

Were you having any drive-ability issues at 92562 with the original HPFP, or just the codes?

[graylens]

Engine drove EXTREMELY rough in April, like it was about to stall out all the time. Also, after replacing the HPFP it did drive like its normal awesome self, so...

[stewbets]

I'd bet your HPFP has gone bad again. There are several reviews of that one going bad in a short amount of time. Unfortunately I've had very bad luck with off-brand parts on this platform, but I certainly don't fault you for trying. I encourage you to download the MHD app and purchase the monitoring module if you haven't already. It's really useful for logging things like this and could certainly shed some light on your fuel pressure issues.

[graylens]

You don't think it could be the low-pressure fuel pump underneath the back seat with those last two codes? Shouldn't even a crappy HPFP make it past 2500 miles? I did contact the Amazon seller of the HPFP to find out what the process is to get a new replacement...

[stewbets]

It's always possible, but I'd put my money on the HPFP. With that said, I wouldn't own this car without having a way to log it. A log would clear this up immediately and it's so easy to do with MHD. Are you stock or tuned?

[graylens]

I'm bone stock. I've seen that app in the YouTube videos by Vehicular DIY, how much is it? I have an Android tablet I could take out to the car.

[stewbets]

https://mhdtuning.com/collections/mhd-flasher-n54

Looks like it's $84 for the monitoring module. You also need a K+DCAN cable to connect to the car and an OTG cable to connect to your device. And after you've resolved your issue, the obvious next step is to FLASH A TUNE ALREADY! Then come the bolt-ons and more aggressive tunes and the never-ending quest for more power! This is N54 life.

[graylens]

I'll settle (for now) for the two complex fuel pumps to deliver the go-juice to my stock setup reliably for now. If I can go over 5000 miles with no problems, then I'll consider messing with her some more to buff her up some...

[Aceway]

I've tried many eBay hpfps. They're all junk. I'd recommend getting one from BMW. There's a lot of things you can use eBay parts but hpfp is not one of them. Good luck.

[BSM n54iS]

Well, actually get one from FCP Euro I'd say for the lifetime warranty. If you wanna save some money for right now ECS usually has genuine parts for less and great customer service too.

But ya water pumps, hpfp (unless you're upgrading) stuff like that you really do wanna stick with oem or oem supplier. Things like engine mounts or control arms or that kinda thing that isn't so sensitive so to speak you can safely get other suppliers and save on the BMW tax. IMO

[graylens]

If I’d known about FCP Euro in April, I would have gone that way. However, for the next three years, at least in theory, I can get a new HPFP if they continue to fail from OSIAS/Amazon. Personally, it torques me off that any single part from BMW gets up around $500, especially when they fail like this!

[Vivek.]

Originally Posted by graylens

If I’d known about FCP Euro in April, I would have gone that way. However, for the next three years, at least in theory, I can get a new HPFP if they continue to fail from OSIAS/Amazon. Personally, it torques me off that any single part from BMW gets up around $500, especially when they fail like this!

Frankly, the BMW part is unlikely to fail this easily. These parts from unknown suppliers are by and large horrible quality. They don't last as long as they should, simply put. To you earlier comment of, 'shouldn't it last more than 2.5k miles?'--not necessarily at all. For an unknown electrical pump getting 3 months or so out of it sounds just about right. Especially when even the legit ones are known to be not-super-reliable.

You can go ahead and keep replacing it under warranty for 3 years but at a certain point I'd hope your time is worth more than the money saved.

[rjahl]

Originally Posted by Vivek.

Frankly, the BMW part is unlikely to fail this easily. These parts from unknown suppliers are by and large horrible quality. They don't last as long as they should, simply put. To you earlier comment of, 'shouldn't it last more than 2.5k miles?'--not necessarily at all. For an unknown electrical pump getting 3 months or so out of it sounds just about right. Especially when even the legit ones are known to be not-super-reliable.

You can go ahead and keep replacing it under warranty for 3 years but at a certain point I'd hope your time is worth more than the money saved.

I'd never throw parts at a BMW problem without logs. Crazy way to spend money and time.

If OP does not want you go MHD, just simple diagnostics in INPA could help. He could even log these parameters using TestO and it's free. Just need a good cable.

My two cents anyways.

[graylens]

INPA cable & software sounds great — it only works with BMW’s? Thanks for all the advice so far. No one with expertise thinks it’s odd that my 335i is throwing completely different codes than when the HPFP first went out in April?

[rjahl]

Originally Posted by graylens

INPA cable & software sounds great — it only works with BMW’s? Thanks for all the advice so far. No one with expertise thinks it’s odd that my 335i is throwing completely different codes than when the HPFP first went out in April?

Yes, BMW specific software.

[BSM n54iS]

There is also the Foxwell NT510 or Schwaben scan tool which can be used on mini and Rolls with the same unit. Easier (not the best) ui and can test pump functions and all that stuff, another alternative that is more expensive but not as involved of course.

[graylens]

The new HPFP is on its way to me from Ontario, California. I'll post my results once I put it in, again...

[graylens]

UPDATE 10/12/20: The new warranty replacement HPFP has cleared the codes, and I've had about 200 problem-free miles, until:

2FBE/30FF in October (Fuel pressure after engine stop, Turbocharger, boost pressure too low)

Dunno about the 2FBE, but I probably pinched a hose on the driver's side replacing the HPFP. Code only throws once at full operating temp, and even when the half engine light is one it drives fine, so I bet it's a small leak. Can anyone with experience guess before I take Layer One off to get to all the turbo hoses?

Thanks again for all the information and help so far!

[Saif2018]

Originally Posted by graylens

UPDATE 10/12/20: The new warranty replacement HPFP has cleared the codes, and I've had about 200 problem-free miles, until:

2FBE/30FF in October (Fuel pressure after engine stop, Turbocharger, boost pressure too low)

Dunno about the 2FBE, but I probably pinched a hose on the driver's side replacing the HPFP. Code only throws once at full operating temp, and even when the half engine light is one it drives fine, so I bet it's a small leak. Can anyone with experience guess before I take Layer One off to get to all the turbo hoses?

Thanks again for all the information and help so far!

2FBE

https://bmwtuning.co/bmw-n54-common-...h%20the%20LPFP.

Have a read through this.

30FF is most likely a boost leak,

https://bmwtuning.co/bmw-n54-30ff-en...-repair-guide/

[graylens]

Those pages on each problem code are an awesome resource! Thank you!

[Saif2018]

Originally Posted by graylens

Those pages on each problem code are an awesome resource! Thank you!

No worries, I found it helpful as well.