[SRLA]

Hey guys, long time lurker, first time poster. My car just died on me, it'll be going somewhere to get sorted because it's still under warranty but I just wanted to understand what's going on if someone has heard of a similar issue on these. This is an e92 N55 335i with the DCT, today under acceleration the engine switched off and there was a strange smoke that smelled distinctively like burnt clutch. It had to be towed back to the house, it cranks but will not start (idrive shows limp mode message but it won't start at all).

I have a CAN cable and the BMW service tools so I quickly plugged in the laptop to get the error codes. The short list is:
- No comms with safety module/restraint system, fuel pump control module and MOST gateway
- Implausible signal on both camshafts, short circuit to B+ on both sensors, and air mass too low

I cleared the memory, tried again and only the 3 comms erros remain (S0180, S0098, S0376). Still cranks but won't start.

I'm thinking the signal faults were just because the engine switched off suddenly? These other 3 do they ring any bells?

[ptpending]

welcome to
https://www.e90post.com/forums/showt...513898&page=20

[SRLA]

Interesting, thanks for sharing. It didn't seem like a bearing issue to me because the engine does turn over (seemingly fine) it just doesn't start. Prior to failing there was no knocking or anything that would indicate a mechanical failure. There's no oil anywhere either the engine is perfectly clean so no holes in the block which is good!

At this point I'm wondering if it's an electrical issue like a burnt ECU (hence the error codes) or if it was something like the timing chain that went and the codes are just coincidental (although I did pull the error logs about two months ago and it was all clear, everything in the car worked perfectly until now).

I'll be arranging to have it taken to a garage this week, and fingers crossed it won't be anything too bad. The more optimistic part of me is hoping it's something stupid like a fuse or a poorly connected harness that just came off.

[SRLA]

If anyone still cares, it was the crank hub that slipped. The clutch smell was from the friction washer. Apparently this is a more common issue with the S55 but very rarely happens on the N55, I was one of the lucky few.

[Saif2018]

Originally Posted by SRLA

If anyone still cares, it was the crank hub that slipped. The clutch smell was from the friction washer. Apparently this is a more common issue with the S55 but very rarely happens on the N55, I was one of the lucky few.

Seriously, first time hearing about crank hub slip on a N55

How much did it cost to fix? 😣

[SRLA]

Still being fixed, the estimate is 4k but depends how many valves need to be replaced (they're like 20£ for intake and 30£ for exhaust each plus VAT!). Seems that earlier n55s were more prone and around 2012 BMW actually upgraded the friction washer. DCT cars are also more prone because of the quick shifts causing sudden changes in engine speed. Not many e90 n55 DCTs around so its not surprising we don't hear of this happening often.

[Saif2018]

Originally Posted by SRLA

Still being fixed, the estimate is 4k but depends how many valves need to be replaced (they're like 20£ for intake and 30£ for exhaust each plus VAT!). Seems that earlier n55s were more prone and around 2012 BMW actually upgraded the friction washer. DCT cars are also more prone because of the quick shifts causing sudden changes in engine speed. Not many e90 n55 DCTs around so its not surprising we don't hear of this happening often.

Ouch! 4k+?

[SRLA]

Yep about 2k for hub assembly, timing kit, valves and gaskets, plus another 2 for labour which is about 25 hours (that works out around 80 quid per hour which is actually reasonable).

Not gonna lie it is depressing but it's either that or scrap the car so not much of a choice at all, it cost me a decent amount of money and I rather like driving it.

[0l0dom0l0]

Ouch.
Interesting to know, I've been looking out for a late N55 DCT car so will bare it in mind.

[SRLA]

I thought I'd share my latest trials with this car. I had a knocking control arm so yesterday morning I replaced that, looked good and solid so put all the undertray covers back on and took it for a quick drive around a twisty road to check the steering and suspension.

Half way through engine coolant low light came on, I wasn't far and just drove it back very gently to find I had lost all my coolant. I took it apart again today and found one of the radiator pipes just came off completely, it looked fine so I reattached it, refilled the coolant, bled it and took it for a drive and it seems to be holding fine. Maybe this just wasn't clipped in properly when they put the engine back on or maybe the clip just isn't doing its job, I'll probably just go ahead a order a new one but yeah, long story short I very nearly burned through my brand new head gasket! I'm starting to think this car might be cursed, and the irony is I went for an N55 over an N54 because I wanted the more reliable engine

I was going through the technical info on ISTA while looking for the pump bleeding procedure and turns out BMW says if the coolant pipes are more than 5 years old we're supposed to just replace them all. These germans must think we're made of money, their idea of making a car reliable is to just consider everything that isn't the engine block a wear and tear item.