No compression on cylinder 1. Sticky valve or piston ring?

Hello guys, I’m in need of some input here. The other day I was driving home and suddenly noticed a dramatic loss in power. I was still miles from home but managed to limp it home on 3 cylinders. Today I did a compression test on the engine and found exactly the results I was expecting…
So I know I lost compression on the cylinder but I’m trying to figure out if its in the top or bottom end. I pulled the valve cover off and turned the motor over by hand so I could physically inspect the cams moving the valve springs and everything appeared to be functioning correctly although I don’t know if it would be something I could see or not if the valve was staying open. Any ideas for me? Things to test? Questions? I’d like to diagnose what needs to be replaced so I can make a decision on whether to repair it or part the car out. Any help would be appreciated. Thanks!

do a wet compression test…squirt some oil into the cylinder then see what number you get… that will tell you if your piston ring is blown/cylinder wall…or iff your valves are sticking

Thanks! I’ll give that a try

If the wet compression test doesn’t change the reading then I would suggest turning that cylinder to TDC and blowing compressed air into the cylinder (you will have to hold the crank). You may begin hearing the compressed air escaping through the exhaust or intake depending on which valve is burnt.


Craftsman makes a very good compression testing kit that will not only test your compression and do the leak down test but also has a hose you can thread into your spark plug hole and hook an air compressor into in order to help determine the issue with your motor.

This is how I discovered a burnt valve on my Saturn. I had air coming out of my exhaust.