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Discussion Starter #1
I have a 2007 R56 Cooper 1.6 n/a with 116500 miles on the clock, bought as a general runabout a couple of years ago. It has done about 20k miles in my family and generally runs fine. Apart from the usual oil leaks (being addressed hopefully) and a new radiator and plastic coolant pipe it has been reliable.
However, over the last couple of months it has developed a misfire on cylinder 1, only on idle and only when warmed up. The P0301 misfire code gets thrown and engine light come on intermittently. Car starts well and idles smoothly from cold, also seems to pull fine without misfire when off idle. Misfires only when its warm and left to idle.
So far trouble shooting and attempted fixes include:
  1. Swap out #1 plug and coil pack with #2., #1 plug a bit black and possibly oily after misfire but works OK in another cylinder, problem only in #1 so does not apper to be spark hardware related
  2. Switch #1 and #2 injector - same problem occurring so I'm assuming the injector is OK
  3. Compression test - all cylinders very close with about 10 bar on compression, certainly #1 within 5% of other cylinders.
  4. Fit new PCV - there was a very small hole in the diaphram, and hose to intake manifold looked a bit oily, but new PCV has not changed anything. I had read on web that excess oil into intake could cause rough idle.
It seems like when engine is fully warm and idling either the injection or spark on #1 is getting shut down. Could this be a wiring issue? I think unlikely as engine pulls OK on all cylinders when off idle, and a wiring problem would likely give misfireat all temperatures, revs and load. Next step might be to aquire some noid lights to confirm if signal reaching injector or coil during misfire.
Carbon build up on a #1 intake valve? I would expect the problem to show when cold as well as hot and compression test when warm was fine.

Any ideas from those more familiar with this engine would be appreciated.
 

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I have a 2007 R56 Cooper 1.6 n/a with 116500 miles on the clock, bought as a general runabout a couple of years ago. It has done about 20k miles in my family and generally runs fine. Apart from the usual oil leaks (being addressed hopefully) and a new radiator and plastic coolant pipe it has been reliable.
However, over the last couple of months it has developed a misfire on cylinder 1, only on idle and only when warmed up. The P0301 misfire code gets thrown and engine light come on intermittently. Car starts well and idles smoothly from cold, also seems to pull fine without misfire when off idle. Misfires only when its warm and left to idle.
So far trouble shooting and attempted fixes include:
  1. Swap out #1 plug and coil pack with #2., #1 plug a bit black and possibly oily after misfire but works OK in another cylinder, problem only in #1 so does not apper to be spark hardware related
  2. Switch #1 and #2 injector - same problem occurring so I'm assuming the injector is OK
  3. Compression test - all cylinders very close with about 10 bar on compression, certainly #1 within 5% of other cylinders.
  4. Fit new PCV - there was a very small hole in the diaphram, and hose to intake manifold looked a bit oily, but new PCV has not changed anything. I had read on web that excess oil into intake could cause rough idle.
It seems like when engine is fully warm and idling either the injection or spark on #1 is getting shut down. Could this be a wiring issue? I think unlikely as engine pulls OK on all cylinders when off idle, and a wiring problem would likely give misfireat all temperatures, revs and load. Next step might be to aquire some noid lights to confirm if signal reaching injector or coil during misfire.
Carbon build up on a #1 intake valve? I would expect the problem to show when cold as well as hot and compression test when warm was fine.

Any ideas from those more familiar with this engine would be appreciated.
yep thats how they end up all do it at some point link below for insight to it all
 

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Discussion Starter #3
So internals probably....... I have checked the cam chain strech and within spec, but I can't really be bothered with a chain change let along a full rebuild. I may try and get it through its MOT next month, but if it fails on emissions (likely given misfire), it will be off to the scrappy I fear.
 

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So internals probably....... I have checked the cam chain strech and within spec, but I can't really be bothered with a chain change let along a full rebuild. I may try and get it through its MOT next month, but if it fails on emissions (likely given misfire), it will be off to the scrappy I fear.
i do a lot of these on all kinds of cars with this engine in it form mini to Citroen to Peugeot all do it think its down to how hot the run as well and super heats the valve stem seals then this leaks oil on to rear of valves,, have seen cars with 50k on them with same issues then add the timing chain stretch,, ive been doing a fixed price on them as got them down to fine art now £850 all in includes timing chain piston rings and stem seals head gasket and bolts etc,, as a engine refresh with after market parts, or £1300 with genuine parts, but chances are the cat and 02 sensors will need replacing as oil kills them off
 

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10 bar shouldn't it be around 130? buying a new coil might help. But I would not suggest anyone to waste their money.
I remember buying a run of 4 coils and over the years and kept the originals. I found out pretty quick after owning the car that it does not need 4 new coils at a time. So I have replaced them over the years steady. I think I have one coil left that sits on a shelf whenever I have misfire issues. And when I need it I order a new one the same day.
Spark plugs it will usually give a red engine light if they get to bad. Red being the worse of the two engine lights. Orange being the lesser. Noid lights are good. carbon build up is something to think about. I would check the intake Vanos for broken parts or clogged up or the exhaust Vanos also if you have it.
I saw a mini cooper for sale last month that had 236,000 some miles on it. It is not impossible for the car to reach that mileage. I would just rebuild it. At that point you have a clean slate with the car under your guise.
Of course I am a professional upholsterer and if the interior is bad it only sets me back a week or so. I have a large enough inventory to re do that. It takes some of the bite out of the quality of the car going bad.
You may have to take it to the yunkyard.
 

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1-bar is 14.7psi ie what we breath at sea level , 147psi ie would be about right for age and wear and on non turbo would be good pressure
 
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