I'm beginning to suspect my engine misfire may be due to either one of two things, carbon build up or the LPFP sensor. I plan on removing my intake manifold and cleaning it over the weekend while I'm replacing my LPFP sensor since it has to be removed anyway and hopefully one of these will fix the issue.

Are there any steps that can be taken or products that will help deal with carbon build up? I'm kind of on the edge about using products like seafoam...too sketchy for my liking.

 

Manual blasting with walnut shells or some type of bristle brush is the only effective method for carbon removal.

 

From what I have read on the direct injection systems, Jim165 is right on. Apparently it is well worth it if they are junked up. I would however use a bottle of Techron before you go that route. It is the only fuel system cleaner that BMW approves and uses. I understand that this doesn't touch the intake but it has been known to show improvement on DI cars for all components downstream. I used it for the first time recently and can tell you that after a tank i am a believer now. Most products are placebo in my opinion.

 

It also seems like the addition of a catch can for the oil vapors circulating from the crankcase will drastically reduce the need to clean the carbon deposits in the future. Just do a quick search on the catch can for the n54...I think its only a $20-$30 item...

 

Yeah I had a $30 Ebay Catch can which was a horrible mess, it would leak from the bottom plug and from the retarded tube on the side that shows oil level. Will either look into a better designed OCC or make my own next time, I'm still not willing to pay $200 for one like some companies offer.

 

I hear ya, best of luck...

 

bg 44k run a couple cans through you have no idea how much this stuff clears up carbon realted problems this stuff is magic snake oil.. seriously though BG Company

 

On direct injection engines such as the N54 (535i), do cleaning solvents still get put in through the gas tank or does it require another method?

 

So I got around to removing my intake manifold while I wait for my low pressure fuel pump sensor to arrive, and I took a look inside. It is completely black and caked and all 6 ports pretty much look this way. I'm gonna take the opportunity to clean it out while I have the manifold off. I've heard of people getting it walnut shell blasted but I'm probably gonna have to research a bit into another approach since I don't wanna spend $500-$800 for walnut blasting.
Link of someone that got walnut blasting on their manifold here REVIEW: Cleaning of intake valves with BMW walnut shell blasting tool - BMW 3-Series (E90 E92) Forum - E90Post.com
And heres my hideous intake manifold



If anyone has any suggestions on approaches for cleaning feel free to throw it out there.

 

http://www.n54tech.com/forums/attach...3&d=1344569400
U can diy it- looks fun doesnt it???