[335idle]

Hello,
Car is at 41,8xx still under warranty. Started to notice this issue after my last visit to the dealer.
When I slow down the rpms spikes/car shutters a few seconds. Also when I come to a complete stop traffic or parking. The car lurches forward or feels as the brakes were slipping. Maybe it's just the rpm spiking as well?
Also get the same feelings bf shifting from R-D
Any ideas thanks !

[BMB063]

Sounds like spark plugs. I have a similar issues and plan to do them in the next couple of weeks. If you haven't had plugs done it sounds like it's time!

[D0Z3R335i]

Originally Posted by BMB063

Sounds like spark plugs. I have a similar issues and plan to do them in the next couple of weeks. If you haven't had plugs done it sounds like it's time!

are you getting any misfire codes? it could need a walnut blasting, left un-modded these cars usually dont need plugs till around 75-80k and coils around 100k.

[BashShah]

1+ on walnut blast.
Check your in brake ports via a borescope with pictures.

DN

[Bavarian Tech]

situation
Intermittently, the engine idle speed may fluctuate up and down or cut off under any of the following circumstances, without any relevant faults stored in the DME memory:
•While driving off throttle (coasting) and braking at speeds below approx. 10 mph

•While idling, low-speed maneuvering such as parking, or if the steering is turned to the full-lock position



cause
Unfavorable DME software

Perform diagnostics using ISTA/D and work through the recommended test modules found using the path below:


Activities / Function Structure / 01 Engine / Engine electronics / [!] Current fault patterns / Engine stops/problem starting engine



Depending on the vehicle and engine variant, program the vehicle using the latest version of ISTA/P only if the current integration level is lower than what is listed below.


Car needs programmed to latest I-level BTW N55 dont need walnut blasted

[BashShah]

Originally Posted by Bavarian Tech

BTW N55 dont need walnut blasted

Just for us noobs here..... Can you explain this last statement as to why a n55 does not need walnut blasting?

DN

[BMB063]

Originally Posted by DarkNemesis

Just for us noobs here..... Can you explain this last statement as to why a n55 does not need walnut blasting?

DN

+1 Id like to know too. Nice to know I won't need it!

[Bavarian Tech]

N55 have a completely different valve cover design.

[D0Z3R335i]

Originally Posted by Bavarian Tech

N55 have a completely different valve cover design.

Yea but it has the same intake manifold and cylinder head, as well as same direct injection system, so what would the valve cover have to do with the n55 not needing it. I have personally seen n55 engines that needed it done have it done and it fixed the issue.

I was a BMW technician for 2 years, and at no point did they tell us not to perform walnut blasting/carbon cleaning on the N55 motor. As a matter of fact, according to BMW, regardless of the software version running in the DME, ALL BMW models equipped with the twin turbo or twin power turbo system require or will require at some time to have the carbon cleaned. Just recently saw a 2013 X3 4 cylinder need it done.

[robthewrench]

Regarding the N55 need for walnut blasting: This has been discussed on several other threads. The general opinion has been that most N55 motors have had fewer problems associated with carbon buildup in the intake. Note that this does not mean you will never see this problem in an N55.

Two reasons why the N55 seems to have less carbon build-up:
1) The N55 has not been in service as long as the N54. This means we may not be seeing N55's that have carbon issues simply because the engine have fewer miles. Time will tell.

2) The oil separator on the crankcase vent of the N55 is very different from the N54. The N55 does a better job of 'cleaning' oil out of the crankcase gases that are recycled into the intake air. This reduces the amount of carbon that builds up in the intake of the N55. I'll see if I can find one of the related threads and post it here.

[Bavarian Tech]

Originally Posted by D0Z3R335i

Yea but it has the same intake manifold and cylinder head, as well as same direct injection system, so what would the valve cover have to do with the n55 not needing it. I have personally seen n55 engines that needed it done have it done and it fixed the issue.

I was a BMW technician for 2 years, and at no point did they tell us not to perform walnut blasting/carbon cleaning on the N55 motor. As a matter of fact, according to BMW, regardless of the software version running in the DME, ALL BMW models equipped with the twin turbo or twin power turbo system require or will require at some time to have the carbon cleaned. Just recently saw a 2013 X3 4 cylinder need it done.

N55 does NOT have the same cylinder head as a N54. Not even close..As a tech, I would assume you would know the difference, nor do they have the same DI system. Matter of fact their two completely different systems. N54 and N63/N74 may need de-carb service at some point. But an N55 or N20..Rather unlikely

N54,N63,N74 are all equipped with Piezo fuel injectors
N20/6,N55,N63TU are all with Bosch solenoid fuel injectors

[D0Z3R335i]

Originally Posted by Bavarian Tech

N55 does NOT have the same cylinder head as a N54. Not even close..As a tech, I would assume you would know the difference, nor do they have the same DI system. Matter of fact their two completely different systems. N54 and N63/N74 may need de-carb service at some point. But an N55 or N20..Rather unlikely

N54,N63,N74 are all equipped with Piezo fuel injectors
N20/6,N55,N63TU are all with Bosch solenoid fuel injectors

11127588249 (n54 cylinder head) 11127646131(n55 cylinder head) different heads but same intake port size, as well as same type of carbon buildup issues. to say that an N55 engine wouldn't require carbon blasting is an absurd and not knowledgeable thing to say.

As far as the DI systems go, they may be different but a Mini R56/57 engine is completely different however they also require blasting, any direct injected car will over time accumulate carbon buildup, due to emissions standards, all of the cars are having their PCV systems geared towards less emissions more maintenance. If you know so much, why dont u tell the over 5,000 people with N55 that have had their engine blasted they wasted their money on an unnecessary service.

[Bavarian Tech]

Originally Posted by D0Z3R335i

11127588249 (n54 cylinder head) 11127646131(n55 cylinder head) different heads but same intake port size, as well as same type of carbon buildup issues. to say that an N55 engine wouldn't require carbon blasting is an absurd and not knowledgeable thing to say.

As far as the DI systems go, they may be different but a Mini R56/57 engine is completely different however they also require blasting, any direct injected car will over time accumulate carbon buildup, due to emissions standards, all of the cars are having their PCV systems geared towards less emissions more maintenance. If you know so much, why dont u tell the over 5,000 people with N55 that have had their engine blasted they wasted their money on an unnecessary service.

Alright, Alright..What anyone wants to do with their money or car is up to them...

[BashShah]

I am getting the feeling that a n55 still may require a walnut blast, but maybe not as frequent as a n54.
If 50~ for a n54.
Then 80~ for n55.....total guess here.

DN