Also, what would be typical for the leak down figures? Finally, how much differential between cylinders would be considered OK? For example, if all cylinders had one compression reading and one was 10-15% lower than the other 5. Same thing on the leak down numbers. I am just trying to determine if the PPI leak down and compression numbers are good or not. Thanks for the feedback.

Pat

 

Pat,

As I recall compression numbers should be 160psi and deviation of any cylinder result should be no more than 10% max.

demosan

 

15% = problem. Put a little (15-20ML) of oil in the cylinder, pull the fuel pump fuse, crank it over a few times and try again.

if it keeps reading that low, you got a problem.

 

General rule of thumb is 18 -20 times your compression ratio on a good and warm engine.