N55 engine went into limp mode

[Ejpatch]

My car went into limp mode this morning . It would not drive. I had to have it towed to the dealer. I thought it might be HPFP. This happened to my 335i with the N54 engine. The dealer is claiming there was un burned fuel in the valves. They say this is caused by driving it a short distance than parking it. Has anyone heard anything like this?

[shah269]

hu?

[Ejpatch]

Should make more sense now

[lastMleft]

hu?

[wadny]

Um, no, I've never heard of anything like that. There is absolutely no reason why you should have any problems driving the car for short trips. It doesn't do the car much good, since it doesn't give the battery a chance to recharge, or give the engine time to warm up, so long term it's not a good idea to drive it like that all the time. But I've been working on cars (including race cars) for over 40 years and I've never even heard of "unburned fuel in the valves" - I don't know what that's supposed to mean.

[MaDoNiOn]

Tell your dealer that, that answer doesnt even autofill when typing it into google lol!

i wonder if there is even a bmw error code for this? or did they strip the engine to find out there was fuel in the valves?

[Ejpatch]

I'm not sure I am going there on Wednesday, I will see what they say. As for "short trips" I didn't take any I did my normal driving the day before the car went into limp mode.

[Newby]

N55 engine is direct injection, fuel is injected directly into cylinder. Unburnt fuel on valves makes little sense. More info is needed, inlet or exhaust side? Manifold or combustion chamber side of the valves? How did they come to this conclusion?

[135Pats]

Your dealer is making very little sense....driving short distances won't let condensation evap from the oil, and isn't great for the car, but it's absolutely not going to lead to a limp mode just because you drove it half a mile then shut it off. That's absurd. Ask them to pull up the codes the car is throwing, i've never heard of the problem your dealer is claiming.

[Ejpatch]

Picked up my car. They are saying the code said all cylinders miss fired causing the engine to flood. That it " should be fine" we shall see ... It's running nice right now

[135IS]

[SAM135iAM]

My commute is about a mile. I only reach about 50 mph tops. Is this bad on my n55 DCT 135i? I have been having some issues with idling and it has stalled twice. I have searched the forums and found a lot of people with this issue, none have spoken about only driving short distances though.

[Scoobs]

^ my N55 did that. BMW diagnosed it as the dreaded HPFP. Swapped out under warranty and as sweet as ever since

[Ejpatch]

I thinks it's the HPFP also, but they are saying it is not...

[loesch]

This happened to a Mazda3 I used to have. Maybe it's the same phenomenon? It's a surprisingly easy fix if it is. Try to start the car with the gas pedal mashed to the floor. I know it sounds crazy but at least in my Mazda it opened the throttle body which allowed the gas in the chamber to be evacuated. Car started right up. Of course you'd let of the gas immediately when the car starts.

[chrisko]

This thread is making me worry since my commute is about half a mile... Maybe I should walk but I like the extra sleep time haha.

But back to topic, sounds like the dealer is giving a BS reason.

Was the HPFP not resolved with the N55 motors?

[Scoobs]

^ apparently not. Quite a few reported cases of HPFP failures in the N55 ( incl mine )

My symptoms were not long cranks - but random stalling / rough idle when pulling up to lights. Haven't had the issue since it was swapped out.

[VMRWheels]

Originally Posted by wadny

Um, no, I've never heard of anything like that. There is absolutely no reason why you should have any problems driving the car for short trips. It doesn't do the car much good, since it doesn't give the battery a chance to recharge, or give the engine time to warm up, so long term it's not a good idea to drive it like that all the time. But I've been working on cars (including race cars) for over 40 years and I've never even heard of "unburned fuel in the valves" - I don't know what that's supposed to mean.

It's pretty common on rotories. You'll need to fully warm the car before moving it and turning it off. It'll flood the rotors with fuel and you can't restart it unless you pump it all out. Normal cylinders, not so much.

[chrisko]

Originally Posted by Scoobs

^ apparently not. Quite a few reported cases of HPFP failures in the N55 ( incl mine )

My symptoms were not long cranks - but random stalling / rough idle when pulling up to lights. Haven't had the issue since it was swapped out.

Yikes.. Do you know if the replacement is a more permanent fix and won't go bad like the rest? Or is it just a matter of swapping out with a functioning one?

[kettasii]

Yes, N55 HPFP still fails. Just got mine replaced after 30K. Now I have 13-51-7-616-446 instead of the original 13-51-7-613-933 HPFP. The bright side is gas mileage and drivability are improved.

[P1]

Originally Posted by SAM135iAM

My commute is about a mile. I only reach about 50 mph tops. Is this bad on my n55 DCT 135i? I have been having some issues with idling and it has stalled twice. I have searched the forums and found a lot of people with this issue, none have spoken about only driving short distances though.

My wife's 135i w/ DCT transmission has stalled twice now. Once was in traffic w/ the AC on and once was in a parking garage, also with the AC on. I see the RPMs drop when the AC is on, then it stalls. Never happens with the AC off though. The car has about 12K miles on it.

[bbbbmw]

I have an old 318 (1997). If I drive it in/out of the garage (like to wash it) the next time I go to start it, it's more difficult. If I do several of those, it almost won't start - I think for the same reason. It's been like that since new.