Hello people, I posted the below in the Mini2 forum, have had 270 views, but no one has responded with any hints so I was wondering if anyone here may be able to shed some light.
Many thanks in advance,
Matt

HI All,
As you will see I am new to this forum, but I want to share my story so far, and also to see if anyone can shed light on what might be happening.
In summary, I bought MCS 2 weeks ago tomorrow, which is the second gen but on a UK 56 plate. (Build was Dec 2006 but registered 12th Jan 2007).
The story is that when I viewed the car there was a lack of power. Trader assured me this would be fixed. Told that it was temp sensor and was replaced. Test drove, fault still there. Then told was the coil which were replaced. I collected the car and drove home. On the way home, started hesitating badly and the EML came up saying fault. (Bare in mind that the above was over a 2 week period before I bought the car and had been without a car for 3 weeks prior).
Anyway, took it to a local diagnostic who said super knock code showing. Booked in with Rybrook Mini Stratford who have been amazing, for a walnut shell de-coke. Car felt 1000 times better, but the hesitation was still there. Advised to change coils and plugs which I did. Fault still there, but then warning came up after hard accelerating from a t-junction. "Engine Fault: Reduced Power". This it certainly did. Felt like 50%. On the phone to Rybrook Mini again and took it to them that afternoon (last Wednesday). This time the fault was Boost Pressure. Parts were checked and all found to be ok. This time an ECU update was advised as this had not been done on the car since leaving the factory. Told to leave with them as can take some time. Picked car up Friday morning, and feels a lot smoother, but still a slight hesitation, like its trying to deliver power, but changes its mind. On a gentle accelerate is seems to be fairly smooth . Overall the power now feels like a normal non turbo Cooper; as if someone has removed the turbo.
The hesitation thing is still present despite new Bosch coils, NGK plugs, a decoke, new OIL and an ECU update.
Has anyone got any ideas about this? I have now spent £700 on this and am really losing patience and money.

UPDATE:
Been doing some varying degrees of exploration with this(and I am no expert at all).
Found that the cooling system had a few "large" air locks. When I say large, I mean bleed screw spluttered air (mostly) and spits of water for around 4-5 minutes after a 60 mile drive. The overflow tank, as expected, was full, but drained rather quickly. Am still checking the bleed screw after pretty much every run.
Have noticed that the car is less hesitant now, but there still seems to be a lack of "oomph", and a little bit of jerkiness.
Will a coolant change help? Have added some more antifreeze stuff, but the original in there was a reddish colour, and also a it rusty looking. Any ideas?

Update Friday 7th March
Car going back to Rybrook Mini Stratford to be checked on Tuesday.Been reading that it could be to do with the timing chain. I don't seem to have any rattle, but could this be the cause of the lack of power? Best way to describe is: Foot flat down, seems to take a while to accelerate. Foot half way/slowly pushed down, more torque and feels more powerful, accelerate more quickly. Double dipping the accelerator peddle seems to give more power too. Any suggestions I can take to the garage with me?? Anyone (really, i mean anyone at all!) have any suggestions?

Update: Saturday the 8th March.
You really couldn't make it up. Engine light on again during moderate acceleration. "Engine Fault: Reduced Power". Now at this point, I thought "Really? Doesn't feel any different to me."
Anyway, got home started tinkering on my own again (thanks for the tonne of suggestions guys, will certainly recommend your pointers to any friends that might need forum advice ), and discovered that the air pipe running from the intake box to the turbo (all stock afaik), is perished/buggered at the point it joins the turbo. I should mention that on Friday I discovered a bit of very hard rubber, just inside said junction, caught in a recess just inside (near, i am guessing a sensor of some description??).

 

First time I see this thread.

Sounds to me like you're getting unmetered air post MAF. As you have indicated, the piping that is attached to the compressor inlet has an issue (although it is not entirely clear from your description what this is exactly - perhaps a picture of the area would help).

Without additional information, I am guessing that the rubber seal that attaches the intake piping to the compressor inlet has deteriorated/disintegrate which could be one possible explanation for the presence of the foreign object you descibed in your last paragraph.

Note that unmetered air entering after the MAF could induce the symptoms you describe (this would explain the boost pressure and super-knock faults). I will add that you should also examine the PCV outlet and piping for possible damange in addition to the condition of the MAF sensor.

When was the last time the coolant was changed on this car? If it is rusty, I recommend having it changed. Does your coolant level remain constant over time?

What is the condition of the oil in this car? Specifically, does it appear to be of a milky consistency?