Ok, patient is my wife's 02 WRX, 100% stock, purchased a year ago with 92k. Car has had all the misfire codes (all cylinders) come an go for the last year but has run well with the exception of a slighty rough idle. Car has not been using oil. Fast forward to Thursday when wife complains of very rough running at all engine speeds, a flashing CEL and little power. Car now has ~97k. Code thrown is 0302 cylinder 2 miss and it obviously is not firing or contributing at all. I run a compression check and find cylinder 2 is only about 90psi on the first check and the others are ranging from 120-130 (engine is only slighty warmed up so I would expect a bit higher readings if it was at oper. temp.) I decide the check compression on #2 again and this time I only get 20-30 psi Max (WTF?) I will now try a cylinder leakage test to try and pinpoint where the lack of seal is. Anyone have any ideas what to look for? burnt valve? valve adjustment? head gasket? any known problem areas? I should also note the wife does not drive the car hard and is not into the boost much. Again, no mods, 100% stock. thanks, Tim
could it be something with the spark plugs? like maybe they are loose or somethign cuasing misfires, and low compression.
I had the exact same thing on my WRX, same cylinder, same code, same runability, It ended up being a cracked piston ring land.
Well just pulled the cam cover so I could rotate the crank and see that both intake and exhaust valves were in the closed position, applied air pressure to the cylinder thru the plug hole and now I can hear a massive leak out the exhaust. Valve clearance on those exhaust valves is only .003"... factory spec is .010". I"m thinking burnt exhaust valves. How often does the valve clearance need to be checked in these motors?
Update on the misfire- cylinder leakage test reveals plenty of leakage into the exhaust, valve clearance on the offending cylinder exhaust valves is only .003"- way under the factory spec of .010" I'm thinking burnt exhaust valve (s). I thought the valve clearance on these motors was good for 100k? looks like this one should have been checked much sooner.
Well sorry to jump in late here. I am going to have to say that this would be a detonation failure. Yes the valves are burnt but it is from det. My guess is that piston looks like the face of the moon.
Are detonation problems common on these motors when stock? We've been running 92 or 93 octane since we bought it, though who knows what the previous owner(s) ran in it. I'm hoping I can get by with a head rebuild, we'll know soon enough when I get it torn apart.
