[beanster64]

Hi all,
The response during acceleration has changed drastically, where there was once a linear power delivery now it is slow to react and feels restricted, its also hangs onto gears (its a DTC)

Diagnostic software has been used to identify any faults and nothing has flagged that would indicate any issues.

has anyone else had a similar fault?

thanks
Beanster

[Phil325i]

Don't know what diag software your using, but based on my experience, I would seek out a BMW Indy who has the latest BMW diagnostic software. I had a mystery hesitation that I couldn't cure. My Indy's software showed the low pressure fuel pump controller was shot. Replacing the controller cured it immediately. I'd never have spotted that myself...

[beanster64]

Hi Phil,
good to know, thanks, im in the S,E too, who did you use?

cheers

[Phil325i]

Originally Posted by beanster64

who did you use?

Probably a bit too far east for you:

http://www.bromspec.co.uk/

[Russbmw]

Reckon it needs the intake walnut blasting.

Had similar on my 2009 335i at motorway speeds if you nailed it, it'd splutter a bit and be hesitant or simply refuse to accelerate in proportion to what my right foot was requesting!

No fault codes either.

I use TWG automotive in Camberley.

Did a write up of it too.....

https://drive.google.com/file/d/0B_j...ew?usp=sharing

[Ruster82]

Mine was doing what sounds like the same thing, hesitation below 3000revs, no codes thrown up, turned out to be an injector leaking. Must have been enough to make the engine fight against it before boost took over and powered through but not enough to cause a big miss fire.

Agree with getting the walnut blast done too, or have the manifold off and clean the valves with intake cleaner.

[Smokey33]

Originally Posted by Ruster82

Mine was doing what sounds like the same thing, hesitation below 3000revs, no codes thrown up, turned out to be an injector leaking. Must have been enough to make the engine fight against it before boost took over and powered through but not enough to cause a big miss fire.

Agree with getting the walnut blast done too, or have the manifold off and clean the valves with intake cleaner.

Thats a bit of a worry that it was leaking but didn't throw a code.

[Ruster82]

Yeah it was through process of elimination that I found it.

I originally decided maybe it was carbon build up on the injector tips since the inlet valves were so dirty, so I removed them all and number 6 was wet on the tip(the rest all had a small amount of carbon on them so was worth taking them all out)

The spark plug for number six was bone dry when I checked them before so not sure if that is a reliable way to check a leaky injector.(Maybe if it is bad enough to throw a code the plug would be wet?)

[beanster64]

Thanks to all for the input, the fault has been sorted, she now runs like a dream!
im sure bg44 helped in the cleaning of the fuel system and from now on I will be only using Shell V power