Hey all. New member, but been lurking around on here for a bit.

I've had a 2010 non-s mini hatch for about 6 months. Around a month ago it started throwing a camshaft position sensor code so I replaced that.
Then a day later it started through misfire codes on cylinder 1 & 3. Just to be safe I replaced the spark plugs and coils on all four cylinders.
That didn't fix anything and I'm still getting the same specific and random misfire codes.

I'm concerned there could be an internal issue, potentially a valve issue due to the camshaft position sensor.
Also, I have read through searching on here that carbon buildup on the intake valves can also lead to these misfires.

Wondering if I am going in the right direction or if anyone may be able to help point me to something else I should be looking into.

Thanks in advance for any help.

 

Well since you have an N12 engine, you don't need to worry about carbon build up. It's no a direct injected engine. Before you throw more parts at the car, take it to a good indy shop and ask them for a diagnostic ... the'll put the car on the scope and see what each cylinder, fuel injector, ignition coil, etc are doing in real time. Then you can change the defective part. I had a similar situation to yours, and my indy shop found the #2 fuel injector was intermittent. That's a hard thing to find without a scope.

 

It is also symptoms of timing being out, cam position and misfire. Could your timing chain require a change out? Ask them to measure the wear using a dummy tensioner. They should have one if they are used to Mini repairs. Compression test and oil pressure depending upon milage before you go throwing more money at it as said above.

 

Thanks for the tips thus far guys. The car only has 75k miles so I was really hoping it wasn't a timing related issue, I did a lot of reading on the common timing chain issues with these cars before purchasing this one since its technically my wife's DD.

I spoke to a local indy shop yesterday that works on minis and they told me to start by simply double checking all my work and giving everything a once over, then if necessary bringing it in for a leak down, so that's where I'm at now.

 

75K is bang on for a timing chain. Some go earlier if not maintained. Mine was beyond specification at 48K miles.

 

Curious, what maintenance can be performed on the timing chain, and where did you find the wear specification? It's weird for sure (bad at 48K) ... mine was like new at 125K miles, only .003" wear across 10 segments.

 

https://www.pelicanparts.com/techart...eplacement.htm

The technique is detailed in this article (and other sources), number 4 gives the correct length. The maintenance I mention is keeping the oil level at the top mark on the dipsitck, there is no other way to protect the chain but low oil will most definitely shorten the life.

 

Ok. I see, they are attempting to measure chain wear by measuring the extension on the tensioner tool. The problem with that is it doesn't account for wear of the guides. Still, this makes sense; you could change just the guides, but that's not very smart. The only way to properly measure chain wear is to measure the center to center distance (pin to pin) across a minimum of 10 segments while the chain is under tension. I have yet to come across a specification (percentage) of allowable chain wear.

Thanks for sharing!

Agree with the oil level bit, the best way to lubricate chain is for the chain to pass through an oil bath. This allows oil to wick into the pin to link joints and keep wear to a minimum. So, if the oil level gets too low, the chain starves and wear will rapidly increase.