[Mangler]

My 08 335i with 50,000 miles bone stock is exhibiting symptoms that the Dealer cannot resolve and I am wondering if anyone else has had this or has found the cause.

Symptom: sputtering acceleration (like a lean misfire) then SES light and codes for mixture control, lean conditions....etc

The Dealer has replaced all the injectors, all the coils and all the plugs with no change. I would think it would be an vacuum leak but with ALphaN and not MAF load input a vacuum leak shouldn't really matter? A boost leak would show up as a code and if it was the turbos there would be more noise and such.

Anyway, any ideas? I am open to all suggestions.

T

[Beemw335]

Have then perform walnut shell blasting and clean your valves then if not they coded the injectors wrong.

[Zebra99]

Originally Posted by Beemw335

Have then perform walnut shell blasting and clean your valves then if not they coded the injectors wrong.

Was just gonna say...
Injectors need to be coded and maybe you need a good old valve cleaning. Damn dude...after this you'll be brand new again lol

[Mangler]

Do they have to pull the head to do the walnut blasting? Would it drive fine for a while then drive like this if the injectors were mis-coded the whole time?

T

[badass335]

I had lean readings bank2 only. They did a smoke test on car and found turbo inlet hose didn't seal. Replaced $20 clamp, and no more lean codes. I believe others had same issue which caused misfires. Worth to look in.

[Jeff@TopGearSolutions]

Originally Posted by ///M_US_E30

Do they have to pull the head to do the walnut blasting? Would it drive fine for a while then drive like this if the injectors were mis-coded the whole time?

T

Walnut blasting only requires removal of the intake manifold.

If you are getting lean codes its not necessarily safe to drive the vehicle. That is a major concern in fact.

[achien]

if you are sure it is a lean mis-fire, check of leaking air at the head gasket, or intake manifold.

I had the same problem with the X5 and it took three visits for the BMW dealer to fix (even though I told them to look at the intake manifold every time).

Could also be the O2 sensor, but check the in-take manifold first.

Originally Posted by ///M_US_E30

My 08 335i with 50,000 miles bone stock is exhibiting symptoms that the Dealer cannot resolve and I am wondering if anyone else has had this or has found the cause.

Symptom: sputtering acceleration (like a lean misfire) then SES light and codes for mixture control, lean conditions....etc

The Dealer has replaced all the injectors, all the coils and all the plugs with no change. I would think it would be an vacuum leak but with ALphaN and not MAF load input a vacuum leak shouldn't really matter? A boost leak would show up as a code and if it was the turbos there would be more noise and such.

Anyway, any ideas? I am open to all suggestions.

T

[Mangler]

Originally Posted by Jeff@topgearsolutions

Walnut blasting only requires removal of the intake manifold.

If you are getting lean codes its not necessarily safe to drive the vehicle. That is a major concern in fact.

Not driving the car. Its been at the dealer for three days.

T

[Mangler]

Originally Posted by achien

if you are sure it is a lean mis-fire, check of leaking air at the head gasket, or intake manifold.

I had the same problem with the X5 and it took three visits for the BMW dealer to fix (even though I told them to look at the intake manifold every time).

Could also be the O2 sensor, but check the in-take manifold first.

Going to talk to the shop foreman today to see what the deal is. I doubt they even know what the smoke test is.

T

[bryce]

i'd recommend a few fairly cheap and easy procedures to help diagnose:

-compression test
-ecu test (could be a failing ecu)
-full fuel system check (lines, sensors, etc)

[bryce]

Originally Posted by achien

if you are sure it is a lean mis-fire, check of leaking air at the head gasket, or intake manifold.

I had the same problem with the X5 and it took three visits for the BMW dealer to fix (even though I told them to look at the intake manifold every time).

Could also be the O2 sensor, but check the in-take manifold first.

+1 would be worth checking intake manifold


head gasket could be checked with a compression test, see above post

[Mangler]

Update:

Just talked to the tech at length and there is something wrong with the ECU and it will not let them get in to update. Someone tried to install the alarm software upgrade without installing the modules and until they find some modules to install in the car the software will not let it go any further.

It runs fine, it pulls hard under full throttle, smooth idle but the part throttle steady state studder is still there.

New injectors (6), new plugs (6),new coils (6), vacuum lines replaced, smoke test performed, fuel system pressure tested.....etc

The lead RTI? guy will be back Friday from a BMW event in Vegas and says he can get around the alarm coding issue to reinstall the cars original order. They can then update the firmware from there.

T

[Mangler]

So I'm driving the car around today. All seems fine except for the part throttle (more than 50%), steady state, acceleration stumbling (will not throw a code). The dealer says that the car has not had a software update since early 2010, but the maintenance records shows the injector and HPFP recall done early this year. Would they replace the HPFP and injectors and not update the software?

Dropping it off in the morning so they can do whatever they say they need to do to the ECU.

T

[Mangler]

Took the car back in last Friday and they still have it and have opened a PUMA case on it. They have reloaded the original order, when the car was built, back into the ECU and they still have a problem? They can't (or won't) tell me what the issue still is just that they are waiting on BMW for something. Are they really this lost? How can BMW not be able to remote into the car and troubleshoot it? Hell I pull over on the side of the road and remote into peoples servers/systems all the time and fix/troubleshoot stuff and BMW can't do this in 2012? WTF?

T

[Zebra99]

Originally Posted by Mangler

Took the car back in last Friday and they still have it and have opened a PUMA case on it. They have reloaded the original order, when the car was built, back into the ECU and they still have a problem? They can't (or won't) tell me what the issue still is just that they are waiting on BMW for something. Are they really this lost? How can BMW not be able to remote into the car and troubleshoot it? Hell I pull over on the side of the road and remote into peoples servers/systems all the time and fix/troubleshoot stuff and BMW can't do this in 2012? WTF?

T

I don't want to scare you, but if they are waiting on BMW maybe they are waiting on approval?

Have they mentioned anything about a master tech or possible approval for replacement? Maybe the turbo seals or something are shot I dunno? :s

[Mangler]

Originally Posted by Zebra99

I don't want to scare you, but if they are waiting on BMW maybe they are waiting on approval?

Have they mentioned anything about a master tech or possible approval for replacement? Maybe the turbo seals or something are shot I dunno? :s

There is an open PUMA case. They have now done the following:

New DME and original car order loaded and then all updates avail
New plugs
New coils
New injectors
smoke test
all iffy vacuum connections and hoses replaced

Same problem. Steady state part throttle acceleration has major studder (like lean misfire).

They are waiting on the RTE to get back to them for the next step. They are looking at the dual mass flywheel now?

Any ideas would be great at this point. They have had the car for 3 weeks.

I know that with my E39 M5 that there is an MAF test that you can do in the OBD service menus. In doing the MAF test and then replacing items that affected that engine, the fuel filter was a major item that hinders performance. Is there any need to check and replace the fuel filter on the N54 setup regularly like with the S62? I remember changing it out on the M5 and the difference was night and day.

T

[JamesM3M5]

I think I read somewhere that a crank sensor fixed similar problems.

One issue with diagnosing a misfire by O2 sensor readings is that any misfire is going to read LEAN no matter what. The O2 sensors pick up on excess oxygen, and whether it's because the injector(s) did not fire or the mix just did not combust, there will be excess oxygen in the exhaust. You can't point to the lean condition as the CAUSE of the misfire, merely the RESULT of unburned oxygen in the exhaust.

[Jeff@TopGearSolutions]

Originally Posted by Mangler

So I'm driving the car around today. All seems fine except for the part throttle (more than 50%), steady state, acceleration stumbling (will not throw a code). The dealer says that the car has not had a software update since early 2010, but the maintenance records shows the injector and HPFP recall done early this year. Would they replace the HPFP and injectors and not update the software?

Dropping it off in the morning so they can do whatever they say they need to do to the ECU.

T

The HPFP and injectors normally require coding and software update.

[Mangler]

Originally Posted by JamesM3M5

I think I read somewhere that a crank sensor fixed similar problems.

One issue with diagnosing a misfire by O2 sensor readings is that any misfire is going to read LEAN no matter what. The O2 sensors pick up on excess oxygen, and whether it's because the injector(s) did not fire or the mix just did not combust, there will be excess oxygen in the exhaust. You can't point to the lean condition as the CAUSE of the misfire, merely the RESULT of unburned oxygen in the exhaust.

Yeah, the lean misfire has been ruled out. There is something else going on. They ran it open loop and the condition was still there. It is very odd and hard to describe. The best description is if you are used to tuning your own stand alone EMS, the ragged edge of lean burn steady state cruise misfiring. It does not occur under WOT, nor standard driving and going through the gears. Only >50% steady state part throttle acceleration. Once the turbos kick in it starts to studder through the RPM band. Very annoying.

T

[DSe93]

I believe I have been experiencing the same issues with my 08 335i e93... I took it in 4 days ago and they diagnosed 2 misfiring cylinders. The next day a specialist took a look at it and they found that the turbos have gone bad.. they're not holding boost pressure like they are supposed to... I believe they are gonna replace my turbos...
I don't really know the exact details of what's going on but I'll have them explain what they've found when I go to pick up my car some time soon and maybe I can post an update... But in your case, have them look into the turbos I guess.
I've had HPFP replaced twice before, I've had all my fuel injectors and what not replaced at different times... it's crazy and annoying...

[MilehighM3]

A few possibilities come to mind here. First of all, it's possible you a plugged cat (or cats) causing excess back pressure.
It's possible that either one, or both, turbos are on their way out. There could be play in the turbos and the compressor wheel is lightly hitting the housing.
Another option is the recirc valves may be opening causing an internal boost leak. Maybe they should swap them of a known good car and see what happens prior to digging into the turbos.
Definitely keep us updated

[Mangler]

Anyone reading this, can you go out and test this for me:

start in 3rd gear at 2500 RPM. Make sure you have enough room to get all the way into upper 5000 RPMs. press the gas until over 50% but less than 75% and hold it there through the RPMs. Is is smooth all the way or do you feel a studder through the revs?

T