I just finished a compression check trying to figure out my stumble problem. The test was done with the engine cold and the TB blades wide open with about 10 revolutions. Both the ICM and the fuel INJ fuses were unplugged. Each cylinder was tested 3 times. All 8 cylinders came in at between 130-135 psi. My question is, is this about right for a 9.0:1 motor under these test conditions? Thanks

 

As long as the highest reading cylinder and the lowest are within 10% of each other,it should run fine.The PSI isnt quite as important...You want the consistancy..if that makes sense to you.