Rough Idle

[rerenatorizlnatoizla]

I have a 2005 RHD Euro spec Mini Cooper S That has 3,000miles on the clock. The vehicle runs fine other than a rough idle that happens occasionally. Recently I upgraded the cylinder head to a complete JCW kit with additional modified camshaft, vibration damper, exhaust header & a throttle body. The car runs great but the rough idle is rougher and if I have to stop quickly the engine stalls but not all the time. The rough idle I can deal with but the stalling sucks. What happens sometimes while waiting in traffic the engine is idling normal and then the rough idle kicks in and the engine stalls and again this does not happen all the time. I thought that the modified throttle body could have caused the engine to stall. I put back the standard throttle body and now it is even worse. Now with the standard throttle body while driving and slowing down the engine will stall before getting to a complete stop. Please advise if anyone has this problem.

Thanks

[RAP]

Hi,

My 13 month old (9,000 miles) unmodified Hyper Blue MCS does exactly the same.

I will wait until the service and get the dealer to sort it.

Regards,
RAP

[ButtonIt]

Same here, my October 2004 build MCS has a rough idle sometimes, normally in hot or warm conditions and in traffic.

[twouptons]

Our stock 2005 Cooper has started playing the rough idle game in the past week.

I'm currently blaming it on the rotten gas we've been getting in Atlanta since Katrina...

-Eric

[MiniService]

There is no fix for your concern, Mini is aware of it and working to correct it, it is due to the untimely activation of the evap purge solenoid, mainly in hotter weatherr. and dont blame mini, many other manufactors went throught the same EXACT thing, just happens to be Minis turn to deal with it

[rerenatorizlnatoizla]

I fooled around with the purge valve by disconnecting it, blocking the intake suction side to the manifold and leaving the other hose free. you don't have to disconnect the plug so that your check engine light does not come on. I will test it tonight to see what the outcome is.

[rerenatorizlnatoizla]

Disconnecting the purge hoses worked vehicle had not stalled or even idled rough. I am very happy. Now I have to wait for BMW to sort out the DME problem.

[xTRUE_BLUEx]

i have a mini cooper s 54 Hyper blue (7400 miles) I have noticed with my car too. You drive on a motor way at 70mph then come to a stop then suddenly the engine will start to shudder and the rev counter will adjust it's self slightly. When i got my car i never really noticed this problem, then i had a new clutch fitted and i noticed this happening, though i don't know if it has been there since day one. I also have a theory that it may be something to do with coasting. If for exaple you put the car into nutral and glide for a while then come to a stop. Then suddenly it kicks in. I'm going to mention the fault when i take my mini in for a service if it gets worce ill take it down straight away

[MiniCooperS+]

Hi,

I have just refused delivery on my MCS+, on idle the engine had a slight tapping, I noticed and passed on the info to the Tech in the workshop. He said he had found the fault and it was the V-belt tensioner, I new this not to be the case but I let him fit a new one. I took a trip down there today and the car is doing exactly the same thing. The car taps and every now and then the engine will hunt (move forward and backward (Starved of air or Fuel)) It also causes some vibration in the car. After convincing BMW to let me put the car on the ram and have a play I’m convinced the Fuel regulator (located under the Super Charger) is shafted in turn this has screwed the fuel pump. The inner vibration I believe is caused by the regulator shutting off and sending a shock down the fuel lines making them vibrate on the car body. I listed to a few other used cars and it seems it is a very common fault but ppl seem to not pick up on it until it gets very bad.

Ill let you know the out come when the car has the new bits on.

Stevie

[MiniService]

there is a fuel regulator under the intercooler, not under the supercharger

[MiniCooperS+]

sorry intercooler!