Hi guys,
My 2006 base Mini 137k has a P3030, I took compresion readings 1,2,4 have 180 psi and 3 has 150 psi, is this difference too much?
Thank you
Pedro K.

 

rule of thumb, no more than 20% difference.
Do a leak down test, that'll give you a better picture of what's happening (ie. valves not sealing, rings, etc)

 

One of life's little mysteries is that the #3 coil connection always gets corroded, while 1 2 & 4 don't.
I think I'd clean that connector, plug wire & plug & run the car for a week or two. That might blow the cobwebs out of #3 cylinder.
Then re-do the compression test & see what you get. (I'm a bit suspicious of 3 identical readings; there's usually a few lbs difference).

 

Thank you guys,
Will do a leak test and also check if it's going thru a valve
And re-check again compresion, I clean the coil terminal without success, got an amazon cheap delphy but have my doubt's, now I'm waiting for a Beru.
Thanks again
Pedro