Quote Originally Posted by jerry clayton View Post
When you are comnecting to a schrader valve, you need a compatible coupling that will compress/open the valve or you won't get any reading----
I'm using an actual fuel injection pressure test kit that included the adapter for the Ford shrader valve. I haven't tried it since the truck started but prior to that, it would show around 42psi when cranking but immediately go back to zero when the cranking stopped.