I am just finishing my install. It is a 05 LS6 from a CTSV into a Jeep if it matters. I had it running for 1 min then it shut down and will not fire again and I am getting a back fire through the intake. I thought a tiing issue so I checked and I am dot to dot. I have not been able to check the crank position sensor yet but I found another issue

I put a compression tester on Cyl 1 and got nothing I mean nothing then I checked all on the Drivers head and no compression on any of them. could this be a head gasket issue? Im not sure what else. I did not have the heads off this motor but it looks like I am going to pull one.

Compression on the other side it fine.

 

do you have an air compressor? put some air in a cylinder and listen for the air leaking,that'll help narrow it down

 

yes I can and will try that, thanks any other ideas?