[redz06]

Yesterday I had my BMW 335i sport package on a road course to do some driver instruction for my granddaughter. The 335i is not normally driven on a road course and is not prepared for same. It also has 95k miles on the clock, but it has a manual transmission, which is the main reason that I picked it for a teaching experience.

For my driving, I pushed the car a bit and after a couple of sessions, the dash showed me a half engine warning light, so I immediately pitted. A borrowed OBDII reader showed me a problem with low fuel rail pressure, so my suspicion was targeted on the HPFP. The code was erased and we proceeded home at a reasonable pace, never exceeding 94 mph with no further warnings. Although my car is a N55 and I have been told that the HPFP problems were resolved with earlier cars, I have to say that I have had a HPFT failure before. As the car was out of factory warranty, the cost for the replacement was shared between me and BMW.

So am I about to experience another HPFT failure on my N55, or is there something else going on?

Another issue that I have with my N55 is that when the engine is idling, from time-to-time it will die. Restart is no issue, but it never used to exhibit this behavior. The engine never did this before. During extending idling in a traffic jam it died at least 10 times in one hour.

[Hoody007]

Could also be the low pressure pump or fuel pressure regulator in the tank.

What is the build date of your 335i? The later N55s got a revised and much cheaper HPFP in early 2012.

[redz06]

I believe the build date on my car would have been in late August/early September 2011. It was a European delivery car, built at the Munich plant. It no longer has the original HPFP in it as this was replaced by a BMW dealership after the original warranty ran out, so probably in 2016 or later.

Since the original HPFP replacement, I have never gotten the half-engine warning light until last Wednesday. As I mentioned before, I was running the car on track when the light appeared. Not full out, but not easy either. Normally the car is a daily driver.

If the new pump is cheaper, it is hard to tell that from the pricing I am seeing at independent parts houses. $1100 to $1400 for the part? Yikes!

[Hoody007]

Originally Posted by redz06

I believe the build date on my car would have been in late August/early September 2011. It was a European delivery car, built at the Munich plant. It no longer has the original HPFP in it as this was replaced by a BMW dealership after the original warranty ran out, so probably in 2016 or later.

Since the original HPFP replacement, I have never gotten the half-engine warning light until last Wednesday. As I mentioned before, I was running the car on track when the light appeared. Not full out, but not easy either. Normally the car is a daily driver.

If the new pump is cheaper, it is hard to tell that from the pricing I am seeing at independent parts houses. $1100 to $1400 for the part? Yikes!

Ah. We have a very similar build date (mine is October 2011). Even with my car being from the very last week of production for the E90, I have the HPFP shared with the N54.

However, the newest revision came out in our original production timeframe anyway, so hopefully it isn't your HPFP. Any long crank issues? Do you remember what codes specifically were logged?

[redz06]

Originally Posted by Hoody007

Ah. We have a very similar build date (mine is October 2011). Even with my car being from the very last week of production for the E90, I have the HPFP shared with the N54.

However, the newest revision came out in our original production timeframe anyway, so hopefully it isn't your HPFP. Any long crank issues? Do you remember what codes specifically were logged?

I do not remember the specific code that was logged last Wednesday. There were no long crank issues at all. I brought my N55 to the pits and shut it down while I went to borrow an OBDII code reader and this showed the low fuel rail pressure. The code seemed to resolve itself. With that result, I drove my BMW home, and there were no further issues. I drove the car today and it was issue free.

But both of these circumstances were less stressful on the engine than what I was doing on track, to be sure. Overall, it is disappointing that my BMW cannot be driven on track without having a serious engine alert such as what happened to me.

[lowrydr310]

Originally Posted by redz06

There were no long crank issues at all.

It might just be a bad fuel pressure sensor. I'm not familiar with the N55 but I had one fail on my N54 which was giving all sorts of weird readings.

[OMEGA412]

Do you have access to any sort of logging software? If we could see the low pressure fuel PSI, as well as your rail PSI, you can determine which of your pumps is failing, but if you didn't have any low pressure fuel pump codes it would most likely be the high pressure. It could be as simple as a clogged fuel filter as well, you really should change those every 30,000 mi at most, I would start with replacing that, if it's like the n54 it should be under your rear driver side seat.

[Hoody007]

Originally Posted by lowrydr310

It might just be a bad fuel pressure sensor. I'm not familiar with the N55 but I had one fail on my N54 which was giving all sorts of weird readings.

So here’s the thing with the N55. It doesn’t have a separate fuel pressure sensor like the N54, it’s built in to the fuel pressure regulator. That assembly also contains the fuel filter. For 09/2011 N55s it’s only available from the dealer, but very reasonably priced, thankfully.

I’d start with that and see if the issue persists. Fixed a separate issue for me, but I never had a 1/2 engine light come on, and had full power at WOT.

[redz06]

FCP Euro has them in stock for $163. Will probably go there vs dealership.

[Hoody007]

Originally Posted by redz06

FCP Euro has them in stock for $163. Will probably go there vs dealership.

Depends on the dealer, but mine was $121. Though parts does like me, something to do with all the money I’ve spent on parts over the years 😂.

If you order the repair kit (16117313791) it will come with two new seals for the fuel pump and filter caps.

[M-technik-3]

Having a corporate account at dealer helps but their prices and everyone else's prices have gone through the roof.

[redz06]

Originally Posted by M-technik-3

Having a corporate account at dealer helps but their prices and everyone else's prices have gone through the roof.

Yes, I will need to check this out. My current plan is to go ahead and use my 335i Sport as daily transportation to see whether this code ever occurs again. It is not a track car and I have a Corvette C6Z06 for that duty, which is already absorbing major funding. I would be amenable to trying the fuel filter/pressure regulator part replacement if I ever have a recurrence of the half-engine warning. I will be carrying an OBDII reader in my car in case this event recurs.

[redz06]

I will add that my expectations of my dealer ever giving me any favorable pricing is very low. Being forced to buy any part from the dealer is always painfully expensive. Without going into long stories, I will just say that if my only recourse was to use a BMW USA dealer for service, I would have sold the car years ago.

[lowrydr310]

Originally Posted by redz06

I will be carrying an OBDII reader in my car in case this event recurs.

Just make sure it is one capable of reading BMW-specific codes. The generic readers don't work beyond basic stuff like giving you a general idea of the faults and clearing codes. BMW specific data gets you a lot more helpful information.