[Dmacc]

So I had been getting a pesky misfire that started over 6 weeks ago, and had continuousy been bringing it in to bmw to get them to fix the problem, but even after they replaced all the plugs and the injectors, there was still a misfire on cylinder 5. Two days ago I brought the car in for the 4th time to see if maybe it was a coil pack that was causing it. Today I got a call from my adviser saying that they had opened a PUMA case with bmwna, and that when they took off the intake manifold, they were able to see plenty and plenty of carbon build up.
He told me that he's just waiting on word from bmwna if they can go ahead and walnut blast my engine. All of this will be covered under warranty.

since below 1k I've been tuned, so that's one reason why I assume I have such bad build up at such a low mileage. As far as I have searched on e90post, I haven't seen a thread of someone with below 30k miles on the car that had to deal with carbon build up? I just wanted to let you guys know that these cars build up REEEEEALLy fast with carbon, so if there are some unsolved misfires that keep reoccurring out there and you think you've tried everything, don't forget to consider carbon build up!

My mods I've run in the last 26k miles are just DCIs, cutback exhaust, procede v5/jb4, and downpipes.

I'll update this thread when I get a call back from my SA but I wanted to open this up for discussion if anyone is seeing similar things happen to their low mileage n54.

[obert]

This is very common with these motors. It will have to be done again so just keep that in mind. I think milage will vary from case to case.

I will be doing the cleaning really soon on mine.

[e90328i]

Wow, mine hasn't been looked at or cleaned ever in 65k miles lol. Did you experience any misfire on stock map? prior to blasting or was it only under heavy boost?

[Dmacc]

Originally Posted by e90328i

Wow, mine hasn't been looked at or cleaned ever in 65k miles lol. Did you experience any misfire on stock map? prior to blasting or was it only under heavy boost?

One of the main symptoms that started appearing was one that you get when you get the code for the coolant sensor gradient. all of a sudden on the freeway, you will just lose power randomly with no warning lights or ses lights popping up. So you have to pull over, restart the car, and everything is fine again. Every time it kept losing power, I would hear the radiator fan come on full blast. And this happened even when I was on the stock map.

[Dmacc]

Originally Posted by obert

This is very common with these motors. It will have to be done again so just keep that in mind. I think milage will vary from case to case.

I will be doing the cleaning really soon on mine.

I plan on getting mine checked again around 60k hopefully if I can hold out that long

[e90328i]

Originally Posted by Dmacc

One of the main symptoms that started appearing was one that you get when you get the code for the coolant sensor gradient. all of a sudden on the freeway, you will just lose power randomly with no warning lights or ses lights popping up. So you have to pull over, restart the car, and everything is fine again. Every time it kept losing power, I would hear the radiator fan come on full blast. And this happened even when I was on the stock map.

Never had a coolant code, but i have lost power under high boost and have heard the fan on really loud. Im not paying 800 for a walnut blast considering I have warranty till 100k so ill have to wait until it causes power loss on stock maps.. only happens with jb4 so far... Should look at the valves anyways at 65k they are probably disgusting.

[benzy89]

Could be that the crap gas out in CA is clogging the valves up faster. There's no way to 100% prevent getting them cleaned eventually, but running Meth/E85 and an OCC can help fight off the carbon build up

[vfeng]

which dealer do you go to that offers walnut blasting? just wondering cuz i asked fremont and they only do the chemical method

[Dmacc]

Originally Posted by vF335i

which dealer do you go to that offers walnut blasting? just wondering cuz i asked fremont and they only do the chemical method

BMW of Mountain view, formerly known as Allison BMW. They're great there!

[Dmacc]

Originally Posted by benzy89

Could be that the crap gas out in CA is clogging the valves up faster. There's no way to 100% prevent getting them cleaned eventually, but running Meth/E85 and an OCC can help fight off the carbon build up

I was running 50/50 e85 with 91 and would notice whenever I started the car in the morning that the cold starts weren't ever able to find a consistent idle, shiv had directed me towards a hardware issue as opposed to a software issue, and turns out he was right!

[Tony_Touch]

I had mine blasted with walnuts at 37K and the car is stock except for bms intake.

[mave198]

At 55k mine were pretty badly caked up. Still in the air how much a oil CC helps.

She is happier now with clean intake valves ...

[Jeff@TopGearSolutions]

I believe it. The OCC is not really for carbon build up in the sense that it will eliminate all carbon build up. With the best OCC in the world this car will still build up carbon on the intake valves because it is a characteristic of DI motors.

The OCC simply reduces the amount of intake in your intercooler and charge pipe and reduces the amount that gets to your valves from blow by. One should expect no matter what they do that around 30K there valves will need a cleaning.

[nafoo]

Pics or ban!

[benzy89]

I'm at 35k now, thinking I'll get it done in the next month

[e90328i]

lol bmw should just make the walnut blasting at an interval of 30k miles for free!!!

[Dmacc]

Originally Posted by e90328i

lol bmw should just make the walnut blasting at an interval of 30k miles for free!!!

It's just a matter of time before another law suit is started for misfires due to rapid carbon build up, or at least an attempt at a law suit haha

[JYohay]

Did ou remove our downpipes and exhaust before you brought it in?

[vasillalov]

Originally Posted by benzy89

Could be that the crap gas out in CA is clogging the valves up faster.

Sigh, yet again for 1 MILLIONTH time: the N54 is a direct injection motor. There is no fuel going into the intake manifold. It is injected directly into the combustion chamber and therefore it has absolutely no contact with the intake valves.

Even if you somehow were able to get the N54 to run on lard, the intake valves would not be in any worse condition than if you ran on European 103 octane jungle juice.

[Dmacc]

Originally Posted by JYohay

Did ou remove our downpipes and exhaust before you brought it in?

I was stock when I went in.

[JamesM3M5]

What oil? The cheap BMW "synthetic" is crap.

[Dmacc]

Originally Posted by JamesM3M5

What oil? The cheap BMW "synthetic" is crap.

Cheap bmw synthetic it was.