One Cylinder Running Rich

[rtoomey641]

Hi 5.7GSIPWTR Had a misfire checked heads had 3 bad valves had them replaced as well as seals and guides and machined both heads. New plugs,wires,cap, and rotor. Engine not running right plugs look ok except 6 is carbon fouled. Compression 170 on all cylinders. Leakdown on 6 is 35% and on 1 is 30% used a tester from Harbor freight had 12psi going in the numbers were in the green area still. What should I look at next?

 

[alldodge]

If you have 30% leak you have some bad issues. A new motor would be in the 5 to 8% range, and a motor with some hours in the 10 to 20% is acceptable. Seeing carbon build up would have me looking at the rings since the heads were just done.

You did have each piston at TDC when getting test results?

 

[rtoomey641]

Yes

 

[alldodge]

I'm thinking you have ring issues. Try increasing your pressure to 80 psi to get a more accurate reading, 60 psi is minimum