I have a 09 R56 N14 with 98K that is throwing misfire codes for cylinders 1,3, and 4. This is my wife's baby and she is distraught with the idea of not driving this thing. As for me I'm 74 and have lost a lot of my interest in wrenching (I recently changed out the thermostat housing and hoses which resulted in a lot of blue words).

So to begin I checked the plugs and coils which were recently changed. They looked good. I then did a compression test on both a cold and a warm engine. I also performed a wet test on the warm engine. During the wet test, I tightened the adapter in 2 and 3 which then gave me slightly higher readings. I was considering performing a leak-down test but don't know if it's necessary at this point. Any help with diagnosing this misfire I would greatly appreciate it. (I can't believe the wife wants a new mini ??)

Cold engine

Cylinder 1 2 3 4

178 150 178 176

180 160 176 176

Warm engine

170 160 174 165

172 160 168 165

Wet test

162 156 155 175

162 160 165 175

 

Swap coil pack 1,3 or 4 with #2 and see if it follows. Misfire is the only code or is there some hidden / manufacturer specific codes?

 

Carbon building or timing chain are good candidates.

Timing can probably easier checked than carbon buildup.

 

I swapped out the coils and still got the same misfire on 1, 3 & 4.

 

I'm beginning to feel like it's the timing chain. Some rattling noise near the front of the engine. It appears to be a tough job for DIY, and the costs of $1,000+ are high. Do the compression results indicate the engine is worth doing the work? Thanks for your reply.

 

How has the oil consumption been?

I bought a '10 MCS with 124k mi this summer. It was burning oil at about a quart/500 mi. I did a compression test and my numbers were nearly identical to yours (not terrible). I also did a leakdown test and saw a range of 10 to 35%. My Matco leakdown tester shows 40% or lower in the green "Good" range, so I (in hindsight, foolishly) decided to install new valve stem seals and call it good. Oil consumption decreased slightly with new stem seals, but piston #3 had a literal meltdown at 127k mi. It was evident when I tore into the engine that I had bought someone else's disaster (piston #2 didn't match the other 3), so your mileage may vary.

I've since rebuilt the engine and it's back on the road. But, if I were in your shoes and had no intention of turning wrenches on the car, I'd probably sell it and move on. I think a leakdown test would be a good idea before making a decision. Good luck!