Can I do a compression test without the wiring connected? I installed a cylinder head and what to check compression before adding everything back on. The starter main wire is hooked up. Wire ground to the head is hooked up, next to the battery. Fuel relay is out. Coil is not connected. There a large green wire in front can't remember were that goes I think to the bottom of the starter for the wiring 2nt ground. The intake is not on. Does the psm come into play to turn the engine over for test ?

 

Why a compression test, out of curiosity? The only things it tests are the cylinder rings.

 

Thanks for the reply. I found a burnt valve on number #2 cylinder. The compression test on the original head was 185,80,185,175. On the replacement head I get 185,80,80,70. I used new head bolts, clean out the bolt holes. The head was decked to. ???????

 

I got 80 LBS on cylinder 2. I pulled the head off I found a burnt valve. So along with a burnt exhaust valve I could have bad cylinder rings to.

Why wouldn't the test check how the valve seal to?