2007 Mini Cooper S R56 Idling Problems

[Minified]

Hello all,

This is my first post, l have recently purchased a 2007 Cooper S R56 Chlli for my wife. We have had it a couple of weeks and noticed that when the motor is warmed up and running under normal temperature it starts hunting or dropping revs when it is at idle in park and more so when in drive. I have read a lot of the forums and people with similar problems have not actually re posted what they did to fix the problem.
The reason i am after an opinion here is you might have had a similar problem and if i can give the mechanics a hint rather than them just troubleshoot and charge me a fortune.
Just a little bit more information, I am running 100% octane and i have put a fuel injector cleaner through it. It has been to the mechanics and they put the computer on it and it didnt register any faults or sensors problems. The mechanic cleaned the air box and looked for any obvious vacuum problems. He handed the car back to me saying he doesnt know what is causing the problem.
Any help would be much appreciated.

[Mattstorm]

My Mini does this, once warmed up and leaned off at idle the rpm should be around 800rpm, mine sometimes is and rock solid, other times it dips down to 500rpm and you feel the shudder through the car then the ECU kicks in and pulls it back up to 900rpm then it settles back to 800rpm. It seems to do it when I come to a stop. Bit weird really and always done it through the 7 months I've owned the car!

[JoehartyR56]

Hi all, iv got a mini cooper R56 i too am having this idle problem and it seems to have been getting worse over the last few months. Also when cold started it can sometimes rev up and then drop right down to a stall. My mate who is mechanic thought it could be the cam tensioners but not too sure. I was wondering id any1 has experianced the car compleatly packing in because of this problem?

[samuir1974]

Quote: Originally Posted by JoehartyR56 (original)

Hi all, iv got a mini cooper R56 i too am having this idle problem and it seems to have been getting worse over the last few months. Also when cold started it can sometimes rev up and then drop right down to a stall. My mate who is mechanic thought it could be the cam tensioners but not too sure. I was wondering id any1 has experienced the car completely packing in because of this problem?

Anyone else seen this issue.

My 2007 MCS does this on cold start occasionally. Then it can be fine for days then it comes back.

Symptom is that it starts tries to hold cold idle revs and fails then stalls. can do it 4-6 times then will eventually idle but lumpily or with a hint of a misfire.

Changed plugs and air filter for now... tried different petrol selection too. Still the same....

HELP!!!

[karlos9191]

If it's when the engine is warm it may be due to carbon build up. Possibly get some redex or bgk 44 to clean the system out. I have seen a few people mention these engines suffer from carbon build up and it can present itself in th way you have described. For £20-£30 it's worth a try and at the very least if it doesn't resolve it you know you have ruled it out for a cheap method and cleaned up the inside of your engine :-)

[Dermottdog]

Hi

Heard a lot about BKG 44. My problem is this. An engine gets carboned up over many, many years and miles. When an adititive such as BKG is added, where does all the carbon go?

It worries me that small bits of hardened carbon will drop directly in the the cylinders and cause damage. Any thoughts ?

[karlos9191]

Not at all :-) and understand your worry.
Basically engine additives loosen and break up the particles and they flow out of the normal exhaust system in tiny pieces throughout the 400ish miles you do with the tank.
Have a little read up on the products if you want and you will understand how they work better and how they won't just clog your cylinders up with all that carbon.

[samuir1974]

Quote: Originally Posted by karlos9191 (original)

If it's when the engine is warm it may be due to carbon build up. Possibly get some redex or bgk 44 to clean the system out. I have seen a few people mention these engines suffer from carbon build up and it can present itself in th way you have described. For £20-£30 it's worth a try and at the very least if it doesn't resolve it you know you have ruled it out for a cheap method and cleaned up the inside of your engine :-)

Thanks for your comment. No issues with the car when warm - holds idle fine.
I think there is some sensor issue somewhere and the car may generally be running lean.

The carbon build up is also a background concern for all Mini owners i guess.
Not a great fan of additives - i prefer to stick with Shell V-power and it has worked well on my Skoda VRS TFSI and VW R36.

[Poprin]

I've been trawling these forums for a while and I can suggest two possible issues. Excuse me if I get the wording wrong here feel free to correct me I’m no mechanic!

It sounds like issues people have with either a) engine coking up which people have already mentioned. b) the exhaust gas recirculation system, sometimes oil can get in the return pipe and as you open the throttle oil gets into the combustion chamber and makes the car run like pants. c) or from my own personal experience an issue with fuel pump, mine used to have a real issue when it was cold and power delivery was lumpy as hell until it got replaced.