Horrible misfire, low compression in 5 and 6

1SLOMK3

New Member
Dec 4, 2010
214
0
0
Arizona
So Ive been Daily driving my car with a boost controller set at 10psi and would occasionally hit fuel cut if I went passed half throttle. Got tired of fuel cut so I took out the boost controller and set it back to stock. I went for a little drive, did a small pull getting on the free way. Boost stayed at 8psi pulled pretty decent. As soon as I pulled off the car was misfiring horribly, sounded like a lawn mower. I limped the car home to find oil flooding the spark plugs in 5 and 6.

ajuqepy6.jpg


I figured that was the cause of the misfire so I cleaned out the oil and installed new plugs. Didn't change a thing. Car still ran like hell so I thought I should check the compression.

Results

160 140 152 160 65 62

anu3u5eg.jpg


The motor was built in 2010 .20 JE pistons, cometic HG with ARPs. Has less than 12K miles. I rarely beat on the car since it is my DD

The car doesn't smoke at all, never has. It has never over heated or ran low on oil. Do you guys have any ideas what it might be? I don't have a leak down tester or an air compressor..
 

atmperformance

New Member
Sep 17, 2013
757
0
0
San jose
put oil on top of the piston and run the compression test again, if it improves you can bet it's rings if it's the same you head is leaking and it's time for another headgasket job
 

super51fan

New Member
Jul 28, 2010
497
0
0
Indianapolis
Your cylinders are probably washed down with fuel causing the low compression. Caused by misfiring. Repalce the plugs and oil soaked wires and clean out the oil. Btw make sure your core plugs have gaskets on them and tighten down your cam covers. If they are not loose replace the gaskets with OEM gaskets. Then drive the car a while and retest compression. Good luck.