Compression Issues

[Liamsggp]

I have a really nice 2008 Explorer. with the 4.0 liter engine. When I got it, I knew it had engine problems. Code scan shows #2 injector, and a couple of misfire cylinders. I started with compression check, drivers' side, # 4 120 PSI, #5 140 Psi and #5 150 Psi. Passenger side cylinders all 180 Psi. Should I go any further. Do I need to find another engine. What is acceptable compression for this engine? Thank You.

 

[94Eddie]

You have a wide spread of compression values that are likely too far out of spec to allow the engine to run properly. It looks like something happened on the drivers side that affected all cylinders on that bank to some extent. I would find another engine and replace the chains and guides before installing it as some insurance against them failing not long after installation.

 

[Turdle]

With all plugs removed, crank engine over. Do you hear tapping noises as it cranks?

 

[Blackhawkxx]

I would do a leak down test.