[creepy coupe]

I here my cars electric pump still running after switching off on a regular basis.even when I've just pulled in out of the garage.

[barbagallo]

This thread almost convinces me that nothing has to be done to the car, performance mod wise. Truly a work of mechanical art.

...but sometimes people just want, want, want....!

[Renus]

Just wanna inform post opener that, my 7 DKG 335i is running with MSD81 instead of 80 for engine management, anyway, very nice info. ^ ^

[DoPedUpM3]

Originally Posted by Shawn_speed

Personally and a number of forum members have experienced High Pressure fuel pump failures. There is a BMW SIB (SI B 12 55 06) that deals with symptoms and warranty work procedures. The Engine management PDF file has a great section and schematic of the pump as well as a great explanation of the role of the high pressure fuel system that makes the second generation DI system possible with precise fuel metering and up to 200 bar rail fuel pressure. It really helps to understand the role of the HPP and it's complexity that obviously caused the early pumps (N54's manufactured between 6/06 to 9/06) to be prone to failure.

Before my car's HPP was replaced, I experienced two episodes that were very different from each other. The first incident at 3500 miles was a case of RPM dropping briefly below 600 at idle and engine running very very rough. Since I was at a light when it happened, I pulled over, rebooted (stop engine, restart) and the problem went away.

The second incident happened around 3800 miles. I was coming up a long incline (6% grade over four miles) and the engine felt like a Honda's. It wasn't rough, just no turbo boost. Again a reboot made the problem go away.

Limp home mode is discussed on page 28 of engine management system which includes complete deactivation of the turbochargers via wastegate valves. I believe I experienced this up that incline.

Around page 8 of the Engine Management PDF file, the explanation of Bank 1 & Bank 2blow off valves give a great insight to another major reason for lack of turbo lag beside the bi turbos and because of the DI. The main purpose of the blow off valves are to prevent pumping action and fluid dynamic problems downstream of the throttle body when driver lets go of the gas pedal suddenly, but engine management also uses them for another purpose. When the engine is idling, engine management spools up the turbos but the additional boost is relieved through the blow off valves. When power is demanded, the blow off valves are closed and the boost is already there. Viola, reduced turbo lag. This would not be possible without DI. The intake manifold downstream of the throttle body has only air in it and no gasoline, hence the blow off of compressed air back to the intake system.

There is an ongoing discussion, which I don't know of the resolution about one or two oil coolers in manual vs. auto cars. Picus in Canada is especially ticked. It is interesting that the PDF files make no distinction between oil coolers in manual vs. auto cars. However, they do talk about two gear box oil coolers for the auto as well as a heat exchanger between the radiator and primary gear box oil cooler in auto cars.

Shawn
Phoenix

Very good infromation,
I too experienced Engine malfunction! Reduced power/ half engine light on an incline going 70MPH. Today my mechanic explained to me my engine was misfiring randomly on cylinders 3/4. He took a look inside of the block and caught a glimpse of some milky residue.. He said my car may have over heated and the turbos could have something to do with it. I will find out what BMW has to say on Friday when they check everything out. lmk what you guys think.

[pimple]

Great info in the documents in this thread. Are there similar documents available now for the N55, by any chance? I noticed a couple pages posted in the following thread that look like they are from the N55 literature:

http://www.e90post.com/forums/showpo...5&postcount=32

[jeamps01]

bump for previous post, any pdfs like this for n55?

[richb811]

Great read guys, thanks for posting

[///MIKE]

great information!! thanks op !

[Sakebomb]

Great Info!

[AlpineWhite335i]

nicely done ksfrogman ... nicely done!

[pHo_e92]

GOOD READ!

[GQ335i]

Fantastic! Thanks!

[GQ335i]

Great write-up!

[Boosted John]

awesome thread...

[Dilla]

great info! thanks!

[cisco002i]

Great Read, thanks

[pimple]

N55 document. Thanks to Kalud and others.

[kiteboy]

very interesting great !!!

is exist same file .pdf for N54 ?

thanks

[amclint]

Awesome post, great to print off and keep. Thanks OP!

[Used2335]

Fantastic write up. What a great piece of engineering!

[TheKuz]

thanks for the post!

[Padfan9]

Originally Posted by Panoz

There is also a BMW 3D-video presenting all of these things in an impressive way. Displays in 3D enviroment the fuel that travels through the pipes to the cylinders ,the "explosion" inside them and then the way to turbines ,and out to exhaust.

I'm trying to convice my friend who works on BMW to give it to me.
Then you know what will happens ,don't you?

How do you like your synapse BOV? I have a 2011 335Is and I am getting a BOV but I am not sure if I want the synapse, tial q or hks, everyone says the synapse is great...also how are your other mods doing?