Last night on my way home from work I decided to open it up just a little a coupe miles from home. When I say a little i mean 75Mph top. Just enough to feel the boost. When I pulled in at home i hear a little tick coming from engine with a very slight stumble at idle. no CEL but definitely somehting wrong. So I open my OBDlink to look for problems and the CEL pops up and i get a P0302 code. I pulled the coils and plugs inspected them and reinstalled in different cylinders to see if codes change. I clear codes and drive on errands today. No more codes but still get the noise at idle and power Might feel a little low. So I run a compression test. It comes out not good. #1- 110 #2-100 #3-110 #4-40. so I pull the cam cover to check for cam/follower/valve problems. nothing presented as wrong. So now I'm asking for your thoughts. please help me think of something other than a new/rebuild engine. because honestly i'm on the verge of pawning this thing off with all the problems i've had to fix. The Mini stealership replaced the high pressure fuel pump a couple months ago and maybe the injector is leaking somehow? Any thoughts at all welcome this is my daily driver and have to get it fixed. thank you

'08 MCS

 

How was your oil level? I'd do a leak down test on cylinder 4. How many miles on your MINI?

Not exactly your issue, but some good advice. https://www.northamericanmotoring.co...n-cyl-4-a.html

 

Any visible smoke from the tailpipe?

 

CR readings around 100 can be obtained with a hose that has large ID or is too long. Your problem is with #4. Take pelican's advice, do a leak-down test, then decide what to do.

 

oil was down 1/2qt. topped up. 122,000 miles. but previous owner had to have the whole top end done from catastrophic timing set failure so it has all new up top. followed the link and after i posted this thread last night i got to thinking about carbon possibly fouling a valve. i hope its that easy. going to do leak down this weekend and possibly scope the cylinder. no smoke that i can see. but getting a oil fuel mix smell from it .

Thanks Pelican,Mini, and Old will try to remember to post what i find.

 

Other possibilities, in a worst case scenario, would be low compression caused by a broken ring / damaged piston / or maybe a valve issue.

Perhaps an inspection with a borescope might shed some light. If you can't find a mechanic with one locally, they are available on Amazon.

 

leak down was inconclusive. going to get a hold of a bore scope and see if i can find that way.

 

Inspect the oil and coolant. Look for mixing between the two, and for "milkshake" that indicates such mixing.

Hopefully you don't have any, which would indicate a cracked head, or block, or a leaking head gasket.

 

what were the numbers from the leakdown for each cylinder?
pull the intake out and look at the intake valves, could be that #4 intake valves are so fouled that it is causing a low compression,...
let us know what you find

 

+1 Yes, what did you get from the leakdown? I'd also be curious about the build up seen on the valves.

 

Hotrod,
What did you find out?
Thanks!