When I came back from work, i put my car in sport mode, it was like 2 month I did not try the sport mode. I make the turbo spool a litle bit but after 15min of running at cruising speed i got 3 cel, p304 p300 p303 . P304 came often and some p303 (mise fire cyl4 , mise fire cyl3 , multi mise fire) , the car was weaker but when I reset the ecu , the power came back but the code came after. When I get hame , the car was vibrating at idle so I shut down the engine and reset the ecu. Start the engine againt for 10sec and it was running good as usual , good idle. Remove all the plug and found oil on the electrode of the cyl4. Test all plug and they are all good.

Is it posible that it is time to change my valve cover? It is now at 100 000km without changing the valve cover? I belive the pcv valve not working properly and shoot oil in the intake so cyl4 suck the oil in and this give me the mise fire on cyl4 and 3 with the oil on the plug.

 

Seems like you're on the right path as engine oil can also leak into the spark plug holes in the cylinder head, contaminating the ignition coil boot. Thoroughly inspect the valve cover gasket and look out for oil residue. The R56 is also known to have issues with the valve cover cracking and leaking. You can see the residue by the coils on the photo below (ignore the arrows). You're also about at the mileage for a carbon clean up. Has that been done yet to your MINI?



Valve cover gaskets here: http://www.pelicanparts.com/catalog/..._pg1.htm#item0

 

Bad news!
I just run a compression test and got 148-148-150-30 , yes 30lbs in cyl4. I will be able to run a leak-down test maybe friday. Can it be carbon buildup on cyl4 intake valve? I made the walnut blast in may 2015 and the valves was not that much dirty. Also I run a inspection cam in the hole of cyl4 and the piston don t look broken

 

That's no good. Carbon could have a part of it yes, but if you don't see any build up it probably wont be your cause. Yes, definitely do a leak-down test on cylinder #4. Check out this thread for some really good info: https://www.northamericanmotoring.co...n-cyl-4-a.html

 

I recieve a PM from ridinDirty and I was not able to answer it becaus is mail box is full, so I decided to give my reply here because it may helps other with similar situation


QUOTE=ridinDirty]Did you get the DashDyno SPD ?
does it read oil temp and pressure ??[/QUOTE]

yes I have it, maybe the best tool I got for my mini. What do you suggest. Looking at oil pressure to see if I have a oil pump faillure? I know at this time , I have 3 healty cylinder. I recieve my leak-down tester gauge, and I will look further this sunday , it will help me to figure out where the pressure is lost.

 

Finaly there is a 80% leak by cylinder 4. So I belive I got piston failure. I have batle tune stage 2 and I often feel a hickup around 2500rpm when accelerating. No code by the ecu so I was beliving that the trouble was a bad sparkplug (miss fire) so I did not investigate further, maybe it was a sing of knock.

Now , I will probably switch the pistons for some cp 10.5. I whant to know if we have full access by the oil pan to change the 4 pistons without removing the head? I whant to remove them by the bottom to see if I need to oversize the engine , If I have no choise, I will remove the head .