Updated: Help: Cutting out..!

[RJS-Z4]

Hi team,

So the most reliable car I've ever owned has developed its first real fault. Started yesterday and now does it rather consistently.

When pressing on, not necessarily wide open throttle, when it gets to about 5k in the rev range it just dies.

I get a barrage of warning lights and it restarts just fine.



I also noticed once tonight that the revs were going mental on the Rev counter, just bouncing around.

All help appreciated, as I'm pretty mechanical but this has me stumped :-(

 

[RJS-Z4]

Ok so a little more digging has found me a fault code, well a number of fault codes, but the one that has a frequency that corresponds with how many times I've had the fault (about 5) is the code '28DD air mass system'

To me this says likely MAF? Anyone else had any experience with this code? Do I remember @machine monkey having this issue once?

 

[AndyBeech]

Try looking for vacuum leaks. A split hose somewhere would lead the DME to believe the MAF is giving an incorrect reading when it's actually the air escaping (or drawing more than it should) somewhere downwind of the MAF. Potentially the MAF itself, if it's never been changed, at that mileage it could certainly benefit from a clean I imagine. I would say something about the DISA valves on your engines but I don't know enough about them to know if that would be an issue or not.
Either way it looks like an air intake issue which shouldn't be too difficult to pin down or expensive to address. Good luck!

 

[Smartbear]

Bouncing tacho could also be a fubard crankshaft position sensor :?
Rob

 

[enzed4]

Judging by the photo, I would guess the fuel pump is cutting out when you're driving upside down?
Sorry - hope it's an easy fix (MAF clean or split intake hose).

 

[RJS-Z4]

Ok so I dug a little further more and found a split on the intake boot. Great, but I don't believe this is the route cause.

I cleaned the MAF, temporarily taped up the split, but nope, it's still got issues. I'm fairly certain now from a days driving about that it's the crank sensor. Got a new one and will give it a go in the coming days as well as replacing the boot.

Thanks for the help so far all.

 

[EdButler]

If it does it consistently, try unplugging your DISA and MAF, that should help eliminate those if faulty. The DISA should open at 4500RPM and if the MAF doesnt detect a flow change, it will likely throw a code.

I'm inclined to agree with AndyBeech however thinking it must be an air leak of some sort - MAF issues are usually caused by air leaks. Make sure you check all the vacuum pipes in the engine bay. Also make sure that your Oil Cap and Dipstick are sealed tightly.

Edit: Not sure why it would be the Cam sensors, that would usually make the car completely cut out and often not start again, not idle poorly. Also tape wont stop an intake boot leak - try Silicone Sealant for a test.

 

[AndyBeech]

If it does it consistently, try unplugging your DISA and MAF, that should help eliminate those if faulty. The DISA should open at 4500RPM and if the MAF doesnt detect a flow change, it will likely throw a code.

I'm inclined to agree with AndyBeech however thinking it must be an air leak of some sort - MAF issues are usually caused by air leaks. Make sure you check all the vacuum pipes in the engine bay. Also make sure that your Oil Cap and Dipstick are sealed tightly.

Edit: Not sure why it would be the Cam sensors, that would usually make the car completely cut out and often not start again, not idle poorly. Also tape wont stop an intake boot leak - try Silicone Sealant for a test.

Yup, I can't see it being the crank sensor. If it was giving funny readings out of tolerance that were giving issues it would surely throw a fault code. The throttle cutting off at 5k rpm isn't a small failing that the DME wouldn't detect and ignore, the air mass sensor fault code surely can't just be a coincidence. INPA would really help here as it would tell you exactly what the car was doing when the fault code was registered, ie. at what revs the engine was at which would probably give a much clearer indication.
EdButler knows more about the DISA stuff than me so I would certainly give that a try. I would always do the simple obvious stuff first before chucking money at parts you may not need. Just my opinion of course, hope you get it sorted.

 

[RJS-Z4]

If it does it consistently, try unplugging your DISA and MAF, that should help eliminate those if faulty. The DISA should open at 4500RPM and if the MAF doesnt detect a flow change, it will likely throw a code.

I'm inclined to agree with AndyBeech however thinking it must be an air leak of some sort - MAF issues are usually caused by air leaks. Make sure you check all the vacuum pipes in the engine bay. Also make sure that your Oil Cap and Dipstick are sealed tightly.

Edit: Not sure why it would be the Cam sensors, that would usually make the car completely cut out and often not start again, not idle poorly. Also tape wont stop an intake boot leak - try Silicone Sealant for a test.

Yup, I can't see it being the crank sensor. If it was giving funny readings out of tolerance that were giving issues it would surely throw a fault code. The throttle cutting off at 5k rpm isn't a small failing that the DME wouldn't detect and ignore, the air mass sensor fault code surely can't just be a coincidence. INPA would really help here as it would tell you exactly what the car was doing when the fault code was registered, ie. at what revs the engine was at which would probably give a much clearer indication.
EdButler knows more about the DISA stuff than me so I would certainly give that a try. I would always do the simple obvious stuff first before chucking money at parts you may not need. Just my opinion of course, hope you get it sorted.

If it does it consistently, try unplugging your DISA and MAF, that should help eliminate those if faulty. The DISA should open at 4500RPM and if the MAF doesnt detect a flow change, it will likely throw a code.

I'm inclined to agree with AndyBeech however thinking it must be an air leak of some sort - MAF issues are usually caused by air leaks. Make sure you check all the vacuum pipes in the engine bay. Also make sure that your Oil Cap and Dipstick are sealed tightly.

Edit: Not sure why it would be the Cam sensors, that would usually make the car completely cut out and often not start again, not idle poorly. Also tape wont stop an intake boot leak - try Silicone Sealant for a test.

Thanks chaps, so I've gone further done some work and bed using INPA on it.

Now I'm not sure if it's my inpa skills, or if it's just a bitch of an issue.

So here's what I've done, sorry for the essay but I really appreciate the help.

Ordered a new lower intake boot, after finding a split in mine. Ordered a seimens crank sensor because it's right next to the above boot, so whilst I've got it all out I may as well change it.

Before I fitted them, I did a code read, the only one of note:

28DD air mass system

So, yesterday I fitted both of those, got rid of the vacume leak just lovely and it fired first time with the new crank sensor. Good stuff.

Cleared the faults with INPA and thought I was done with it.

Took it for a 20 minute test drive, beautiful.

Then, went to use the car, got up the road, cut out at a junction idling. Wouldn't restart straight away but did, then it did this five or six more times and I limped it home. The cutting out now has no rhyme or reason, slow moving, fast moving, approaching a junction, whenever.

Got it back with the help of the AA, wouldn't start on the drive, and if it did, it wouldn't run for long.

Fault codes were:



I think the top one is due to him trying to connect and failing, and I've always had the oil one due to fitting a non genuine oil level sensor years back.

So basically as far as I can tell, nothing that should be making the engine turn over and not fire?

I cleared these and then the engine started, but running for a little while, it cuts out again.

I then started playing with the test stuff in INPA, but I was a little bit clueless, changing vanos values and such like. A few things made the car cut out, but it seemed to be when setting the highest value was I wasn't surprised.

So, then I start getting this code:



And then this one.



Now, at the moment the car is starting every time, but I haven't the balls to take it for a drive. As if it cuts out sometimes it just won't go again and I'll be stranded.

For reference, I've also tried starting it with the MAF unplugged when it hasn't been starting and this changes nothing.

Who's the technical masters on here? Because I'm stuck as buggery.

 

[AndyBeech]

That's a bit of a mess buddy

Doing a quick bit of googling doesn't make for good reading, ie: DME failure. The RAM error is certainly not common and to be honest I don't think that has anything to do with the AA chap not being able to connect as such, more that he could connect but the DME couldn't access it's RAM on it's self test which I believe is where all the maps, parameters for the engine are stored. I could be slightly off with that but either way it's critical to the car functioning properly, if the car can't access that data at a certain point for some reason then it would stand to reason the engine would cut out, much like a computer would crash if it had faulty RAM.
It seems rare but entirely possible the DME has developed a terminal fault. Here is a bulletin from BMW that seems to point to that as well:
(Your DME is included in this bulletin)

SI B 12 49 06
Engine Electrical Systems April 2007
Technical Service
This Service Information bulletin supersedes S.I. B12 49 06 dated
November 2006.
designates changes to this revision
SUBJECT
DME MS45 - FC28B2, 28AA, 28AC; Internal RAM Faults
MODEL
E46 M54 with MS45.1 from 9/00 to 7/06
E83 M54 with MS45.0/MS45.1 from 9/03 to 9/06
E85 M54 with MS45.0 from 10/04 to 1/06
E60 M54 with MS45.1 from 9/03 to 3/05
SITUATION
Customers may complain about a crank/no start or a rough start situation.
The "Service Engine Soon Light" or the DSC light is illuminated, and one
of the 3 scenarios may apply:
FC 28B2 "rpm limiting reset " is stored in the DME together with one, or
more of the following faults which are caused by the 28B2:
FC 28AC - "nominal torque",
FC 2796 - "throttle flap: adaptation wrong",
FC 27A1 - "throttle flap: start check",
FC 2869 - "DME self diagnostic: RAM check failed".
FC 28AA "idle speed regulator" is stored in the DME.
FC 28AC "nominal torque" is stored in the DME.
CAUSE
Fault codes 28B2, 28AA and 28AC indicate an internal DME RAM fault.
PROCEDURE
Perform the appropriate DIS/GT1 test modules for the 28B2, 28AA or 28AC.
Replace the DME if prompted by the DIS/GT1 test module results.
Important: Do not replace the throttle body for the throttle faults,
stored in conjunction with FC28B2, even when the test plan recommends to
do so.

It may not be this but your symptoms are very similar. Think it's time to get a dealer/specialist involved or if you can, as a start, find someone with DIS on a laptop and follow the procedure listed above and see what happens.....BMW would charge about £70 to go through the diagnostic procedure I believe and would at least give you a definitive answer.

 

[EdButler]

Eek well found AndyBeech, it does look like an ECU issue as stated in the bulletin

 

[RJS-Z4]

That's a bit of a mess buddy

Doing a quick bit of googling doesn't make for good reading, ie: DME failure. The RAM error is certainly not common and to be honest I don't think that has anything to do with the AA chap not being able to connect as such, more that he could connect but the DME couldn't access it's RAM on it's self test which I believe is where all the maps, parameters for the engine are stored. I could be slightly off with that but either way it's critical to the car functioning properly, if the car can't access that data at a certain point for some reason then it would stand to reason the engine would cut out, much like a computer would crash if it had faulty RAM.
It seems rare but entirely possible the DME has developed a terminal fault. Here is a bulletin from BMW that seems to point to that as well:
(Your DME is included in this bulletin)

SI B 12 49 06
Engine Electrical Systems April 2007
Technical Service
This Service Information bulletin supersedes S.I. B12 49 06 dated
November 2006.
designates changes to this revision
SUBJECT
DME MS45 - FC28B2, 28AA, 28AC; Internal RAM Faults
MODEL
E46 M54 with MS45.1 from 9/00 to 7/06
E83 M54 with MS45.0/MS45.1 from 9/03 to 9/06
E85 M54 with MS45.0 from 10/04 to 1/06
E60 M54 with MS45.1 from 9/03 to 3/05
SITUATION
Customers may complain about a crank/no start or a rough start situation.
The "Service Engine Soon Light" or the DSC light is illuminated, and one
of the 3 scenarios may apply:
FC 28B2 "rpm limiting reset " is stored in the DME together with one, or
more of the following faults which are caused by the 28B2:
FC 28AC - "nominal torque",
FC 2796 - "throttle flap: adaptation wrong",
FC 27A1 - "throttle flap: start check",
FC 2869 - "DME self diagnostic: RAM check failed".
FC 28AA "idle speed regulator" is stored in the DME.
FC 28AC "nominal torque" is stored in the DME.
CAUSE
Fault codes 28B2, 28AA and 28AC indicate an internal DME RAM fault.
PROCEDURE
Perform the appropriate DIS/GT1 test modules for the 28B2, 28AA or 28AC.
Replace the DME if prompted by the DIS/GT1 test module results.
Important: Do not replace the throttle body for the throttle faults,
stored in conjunction with FC28B2, even when the test plan recommends to
do so.

It may not be this but your symptoms are very similar. Think it's time to get a dealer/specialist involved or if you can, as a start, find someone with DIS on a laptop and follow the procedure listed above and see what happens.....BMW would charge about £70 to go through the diagnostic procedure I believe and would at least give you a definitive answer.

Thank you so much for taking the time mate, I really appreciate it. Good find with those codes etc.

I'll get it into Bmw and see what they have to say.

 

[2dogs]

Had the same symptoms as you, its turn out to be the TB new one fitted 3 year ago and all good
May help!

 

[RJS-Z4]

Had the same symptoms as you, its turn out to be the TB new one fitted 3 year ago and all good
May help!

Interesting.

I've unplugged the MAF and it seems to run better, hold idle moderately well and it doesn't ALWAYS cut out about 5k, sometimes it catches itself. Bet a new TB was expensive?

 

[Mike6]

No expert on this problem but how old is the battery. If its fairly old might be worth replacing or at least disconnect the battery for a while and see if fault still exists when reconnected.

 

[RJS-Z4]

Well, it's resolved. At a massive cost.

I did everything possible, found an air leak and fitted a new part to resolve, fitted a new crank sensor just incase, then started driving everywhere with the laptop running to try and diagnose....

And yep, in the end the chap above was right, the DME unit had given up. Sad times.

However it's all sorted now.

 

[EdButler]

Glad it's sorted. Shame it was such a major part

 

[vester86]

i'll share my experiences with this same fault in my 2002 Z4 2.5i

i've had the same start problems for months (starting in oktober, gotten worse in december) when the weather turned colder this winter, and decided not to change my DME/ECU but to give my ECU an software update through the dealer. faultcode in my situation 28AC nominal torque / Internal RAM Fault
i updated the DME at the end of january this year (2017) and the problem never occured again.

i'll guess that this problem is gonna be more common in the future, as the car's getting older and one or more "bits" inside the DME tend to fall over, so for future reference: try updating your DME first before spending lots of money on a new DME.