I got 07 mini cooper (non-s) with 77k. I'm having idle problem since 6 months ago, I went to several mini specialist shop to find out what the problem is, however nowhere found out.. so I took it to the dealership (my final decision) for diagnosis. I spent $140 for diagnosis and they said my car has problem but it's hard to find out the problem in one hour!! wth? I just took it back and went home and checked the serivce statements. it said water pump need to be replaced. my question is that have you suffer idle problem as well because of water pump?
p.s no check engine light on..
this is what the service statement says
Possible ignition coils interrogated fault memory and found no faults in dme, checked spark plugs and found NGK spark plugs for N14, checked iginition coils, visually ok. performed compression test and found cyl 1 at 190, 2 at 190, 3 at 185, 4 at190, compression ok. test drove vehicle with isid connected and checked diagnostic query, found at times all cylinders misfire at different times. need more diag time to swap ignition coils and test drive again.
Water pump leaking.

 

First thing do you have a Droid or Iphone? Second, go get an OBD reader which if you have a Droid I have got a great tool to suggest. Third, most likely it is carbon build up. It seems to be the number one cause of idle issues. Suggestions are block the passenger PCV off or catch can that side. Also catch can the other side. If you want to spend some money but, want some added protection Water/Methanol injection prevents carbon build up all together.

 

You did not say specifically what your problem at idle is. Rough, low/high, does not idle/ stalls. My experience with nonS engines that don't idle smoothly is the engine oil level is usually very low. If you had a bad coil or plug you would have a misfire and a check engine light would be illuminated. Other causes of poor idle would be intake leak (to include loose oil cap or dipstick) would also most likely be accompanied with a check engine light. A problem I have seen that may or may not set a check engine light and may cause poor idle is a worn timing chain. This is harder to diagnose as the nonS engine does not rattle like the S engine when the timing chain is stretched. You must check cam timing. Lots of things can effect idle quality. May take more than an hour diagnosis.

 

Disregard what I said about the catch can and carbon build up that is a turbocharged MINI problem. Regardless though get a scanner it is a lot cheaper then the $140 a pop diagnosis that most places will charge you.

 

The n14 engine is the turbo, so you have the wrong plugs in the car. That can't help, but it shouldn't be the whole problem. It's good that your compression is good, that means that it is not excessive engine wear. I would get the right plugs and pay the dealer for another hour. Mystery part swapping can cost you more than the diagnostic fee.

Mike

 

After my car is warmed up and drove several miles, when fully stopped the car and accelerate 1-5mph then leave the pedal, idle goes down to 400-500 rpm with vibration and back to 700 rpm. it happens all the time. every morning when i start up the engine, engine makes unstable noise with rough idle and engine makes ticking noises(even after changed engine oil). It's really weird that there is no engine light on (that's what dealership said as well). I replaced spark plugs and cleaned up throttle body.
p.s cooling fan also operates everyday after driving 10-15 miles.

 

Ok lets start with the engine cooling fan. The engine cooling fan is activated under two circumstances. First engine temperature reaches aprox. 105 deg. C.. Second A/C is activated and refrigerant pressure triggers pressure switch. So your engine fan coming on after 10-15 mins may be normal. You may have an issue if your fan is coming on and you have not met one of these two criteria. Typically the issue is a coolant leak causing an air pocket to form around the temp sensor located in the thermostat housing. A tell tell sign of this is the engine cooling fan stays on for an extended period of time after turning off the engine.

As far as the noises you are hearing. Some noises may be normal. The n12 engine has a lot going on and isn't known for being a quiet engine. Unfortunately with out hearing what your hearing there is no way to tell you if they are normal or not. One noise that people commonly mistake as an engine noise is the fuel tank vent valve. It is activated shortly after engine start up and produces a loud ticking noise.

Finally, your idle issue. Most of the things I can think of that would cause this symptom would probably store a fault code in the DME. I will tell you that there are faults that are stored that you may not see if you are using an generic OBD scan tool and can only be seen using the factory scan tool. Especially if there is no check engine light. As I mentioned before about the only thing I've encountered that may or may not store a fault (depending on the severity) is the timing chain stretch issue. The DME can adapt vanos (Cam timing)to a certain extent but it may be slower to respond if the chain is stretched. I don't think spark is the issue. It is pretty closely monitored and would set a misfire fault. You may check crank case vent pressure. Maybe transmission adaptations if you have an automatic. Hope this helps!

 

Sadly the computer doesn't necessarily log any codes for rough idle - my `12 MCS ran rough, and hesitated occasionally for 1 1/2 years with BMW denying there was a problem before the car finally threw a CEL. It happened to be only #1 cylinder in my case and happened to be an injector... The OP said his missfires were on all the cylinders, so I would doubt an injector there.

This is a good one!

This makes me think either fuel pump related or a sensor (many could do this) miss reading. I bet you'll have to pay BMW for the diagnoses - good luck!
E