Hi everyone,

I am tracking down a misfire that isn't spark, fuel, or air.... The cylinder with the misfire has no compression... I took the valve cover, and rocker arms off thinking maybe I could find or see a broken valve spring. Do I need to remove the springs to tell if they are broken? They all "look" good from what I can see... I am hoping to avoid pulling the head but am not opposed to it if I need to.

Any help or suggestions would be appreciated. This is a 2004 JCW R53 with 130k on the clock.

Thanks!

 

If you check the valve springs closely, you can see if the springs are broken or not.
I think that a burned valve is a more common issue.

 

To verify the valve(s) are the problem, do a leak down test.

 

Thanks for the tips. I have inspected the springs very closely and they appear to be just fine. I will do a leak down (well, have someone do a leak down test). Thanks for the help!

 

In case it helps, I just discovered a broken intake valve spring only after looking at it several times. It is broken right at the bottom so it was hard to see. It has worn a little hole in my spark plug tube which is what got me looking. Strangely I have not had any major symptoms.