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Discussion Starter #1
hi,
im having another unsuprisng issue with my 2009 n54 535xi! :mad:

rough idle (more than occasional)
and long crank startups ( occasional)

other people on the forum claimed dreaded HPFP so i went to dealer for evaluation (because of 100,00 mile warrenty on the pump) , they said it was the low pressure fuel sensor not the pump, the pump looked as it was replaced before because the part number was the one they were replacing the hpfps with) there price was ridiculous so i took it to a bmw specialty shop.

So i paid the specialty shop for the evaluation, they said they didnt find anything wrong but there was a code for the fuel sensor, and recommended a valve cleaning (walnut blasting)
$800 later got my valves cleaned and the sensor replaced, STILL DOING THE SAME THING :(

Called up the dealer i originally went to and told them the story, the service advisor was also confused on what the issue was so hes going to talk to the tech tomorrow and let me know?

Does anybody have any idea what the hell this issue could be? :cry:

could this be related to:
valve cover gasket,
sticky throttle,
bad gas,
or the valves?
 

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could this be related to:
?
valve cover gasket: No, unless there is a huge hole, but never seen anything like that
sticky throttle: Not sticky but maybe you could clean it. Any sign of rich mixture? (reading the oxygen sensor data)
bad gas: too much E85 in gas?
or the valves: No, they are happy and super clean now

Injectors? any sign of clogged injectors? like running lean (again reading the oxygen sensor data)
Spark plugs? I replace mine every 60k miles
 

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N54 - Rough Idle & Long Cranks...

Try pushing it to redline after its fully warmed up, basically you're looking to force a misfire. Check codes, hopefully that's what you get. Also pull your plugs and inspect them to see if they're soaked in fuel. I'm personally a BMW tech and just replaced my injectors having the same issues you do. I've had my 535 for about three years now, after replacing my injectors I now know what a smooth idle is...lol
Also these injectors really don't clog, in fact I've never heard of them clogging. They leak, like crazy.
 

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Discussion Starter #4
Try pushing it to redline after its fully warmed up, basically you're looking to force a misfire. Check codes, hopefully that's what you get. Also pull your plugs and inspect them to see if they're soaked in fuel. I'm personally a BMW tech and just replaced my injectors having the same issues you do. I've had my 535 for about three years now, after replacing my injectors I now know what a smooth idle is...lol
Also these injectors really don't clog, in fact I've never heard of them clogging. They leak, like crazy.
Thank u for the tip, I will hear what my advisor has to say once he's spoken to the tech, and ill talk to him about the fuel injectors and get his opinion, u dont happen to know howuch would a fuel injector replacment would cost on the n54 would you?
 

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Discussion Starter #5 (Edited)
There weret no codes for oxygen sensor or any misfiring issues, as far as the computer knows everything is reading normal.
And I just had my coils and plugs changed, slight oil leak but nothing major, no changes, and what I meant by the gas is maybe the previous owner had been running on regular gas instead of 90ish octane the car is supposed to take.
 

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There weret no codes for oxygen sensor or any misfiring issues, as far as the computer knows everything is reading normal.
And I just had my coils and plugs changed, slight oil leak but nothing major, no changes, and what I meant by the gas is maybe the previous owner had been running on regular gas instead of 90ish octane the car is supposed to take.
You could give it a try with a Chevron Techron fuel system cleaner. It helped with my "clogged" injectors.
 

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Try pushing it to redline after its fully warmed up, basically you're looking to force a misfire. Check codes, hopefully that's what you get. Also pull your plugs and inspect them to see if they're soaked in fuel. I'm personally a BMW tech and just replaced my injectors having the same issues you do. I've had my 535 for about three years now, after replacing my injectors I now know what a smooth idle is...lol
Also these injectors really don't clog, in fact I've never heard of them clogging. They leak, like crazy.
On my older car that doesn't have direct injectors I had clogged injectors, but in my case they couldn't fully close due to being dirty so they leaked into the intake manifold and the rpm went high after every start. One bottle of the Chevron Techron solved my problem.
 

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Discussion Starter #8
Try pushing it to redline after its fully warmed up, basically you're looking to force a misfire. Check codes, hopefully that's what you get. Also pull your plugs and inspect them to see if they're soaked in fuel. I'm personally a BMW tech and just replaced my injectors having the same issues you do. I've had my 535 for about three years now, after replacing my injectors I now know what a smooth idle is...lol
Also these injectors really don't clog, in fact I've never heard of them clogging. They leak, like crazy.
BTW if I replace the fuel injectors myself, is there any special coding required afterwards or is it just a plig and play, im not really a specialist persay so im limited to a toolbox full of metric sizes lol
 

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BTW if I replace the fuel injectors myself, is there any special coding required afterwards or is it just a plig and play, im not really a specialist persay so im limited to a toolbox full of metric sizes lol
they need adaptation
 

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Hey whats up man.... I was having the same exact issues you are having. I replaced the HPFP, the low pressure sensor, and then I had the injectors done. The only thing that I had to pay for was the sensor and line. The injectors and pump are under warranty. I would try another dealer if the one you are dealing with is giving you a hard time.

Jason
 

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N54 - Rough Idle & Long Cranks...

The injectors are piezo, which is a mineral that eventually deteriorates. So injector problems are a given, especially if they are the older index injectors. Customer pay, all six injectors prolly somewhere in the 2k range I think? I know my price is $1400 for 6.
To do the job you would need a 17mm open end, 14mm open end, small pick, 8mm 1/4 socket, 13mm 1/4 socket, T20, and something to pull the injectors, tool company sell em for about $60, it's basically a small slide hammer.
You can adapt the injectors yourself if you buy the software and cable to connect to your car. There's ton of info on this entire procedure all over these boards.
Also I believe the injectors are covered up to 82k and the hpfp to 120k
 
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