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Discussion Starter #1
Hi

Just alittle update on the fist months of ownership of the M6.

The car is running great, no oil consumption during the first 1600 miles at all and its a joy to drive. I have become good friends with the SMG as well. I actually like to caractheristics. Its not ideal of driving in heavy traffic, but I never do that anyway.

But I have 1 problem I need some input on.

WHen I drive full power over some time, full on 3rd until redline, and/ or rull in 4th the engine goes in limp mode. I seems to happend at around 7500 rpms ++.

According to the diagnostics the report is that the fuel pressure is to low. I had 3,2 Basr at 7700 rpms against 6,x bar that should have been the pressure.

The error message has sometimes disapeered after a few start/stop, but the last time it did not go away.

On the latest diagnostic I got this errorcodes:
2786
2787
2788

The fuelpump and fuelfilter was changed before I bought the car. Also the pressure sensor is new.

Does any of you tech guys have an idea where the problem is hidden?

Erik
 

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There are 2 fuel pumps in fuel pump housing. The second one activates under high load or demand. Without looking up those codes you posted, it sounds like the second pump is not activating at high rpm. On the M5 there are 2 fuses, one for each pump. F30 in the glove box and F72 in the boot. Check to see if you have a blown fuse.
 

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Discussion Starter #3
Thanks, I did not know that, I will check. Can it bee this simple?

It seem to me like the car has full power during WOT, my tech support asked me to drive the car for 400 km and do let the engine work hard all the say from low rpm and as far as I risked doring. ( We have a 55 mph speed limit with serious punishment if ignored)
The reasson for this was that they wanted to check/compare something I belive was the adaption values.
It turned out this reading was well inside the limits.
'
Let me know if you find time to check the codes,

Erik
 

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Discussion Starter #4
Not much input here.

The tech support has not yet been able to pinpoint exactly what cause the problem I am having.
Last test was some kind of leakage test, I believe it was used some kind of smoke with color to check for leakage. Everything was OK.
Next step is to order a new Airmassmeter ( Npt sure if that is the correct english term) In german I believe it is called LuftMengeMesser???
The tech at BMW AG has an idea that it is some kind of clogging in the fuel system, and have suggested to change all lines and hoses from the fuel tank to the engine.

Any thoughts?
 

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I went out and did a cold start while taking a video of my fuel pressure gauge. This checks both pumps and confirms no leaks. I would at least start here and get a gauge on your car to check. As you can see, both pumps run on start up and when the cold start map is done, the secondary pump shuts down and the pressure drops to 40 psi. Also notice when the car is turned off, the fuel pressure spike up and should stay there for a while. If it decreases on shut down then you have either a leaking injector or the one way check valve in the pump is faulty. My pressure stays up there for hours. I would make sure yours mimics mine before they replace all the lines etc. Maybe they already have.

https://www.youtube.com/watch?feature=youtube_gdata_player&v=yBL8VLXPJSI&app=desktop
 

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Discussion Starter #6
I went out and did a cold start while taking a video of my fuel pressure gauge. This checks both pumps and confirms no leaks. I would at least start here and get a gauge on your car to check. As you can see, both pumps run on start up and when the cold start map is done, the secondary pump shuts down and the pressure drops to 40 psi. Also notice when the car is turned off, the fuel pressure spike up and should stay there for a while. If it decreases on shut down then you have either a leaking injector or the one way check valve in the pump is faulty. My pressure stays up there for hours. I would make sure yours mimics mine before they replace all the lines etc. Maybe they already have.

https://www.youtube.com/watch?feature=youtube_gdata_player&v=yBL8VLXPJSI&app=desktop
Tanks a lot. Nothing has been done yet. I Will check This with my guys on monday.

Erik
 

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Good call on the bleed down check Bill, never trust these injectors...make sure the rail holds pressure without it falling when the engine shuts down.
 

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Discussion Starter #9
any updates erik?
Not yet. They Are Working on the Car When they have some spare time.

The problem is that we Are not 100% sure what cause the problem is. BMW Germany telts us to change all hoses and theys hold have some experience, but it does not feel right.

All relevant testmoduls has been done, but no 100% conclution Can be made?
 
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