Runs with the can sensor plunged out

Hello I have seen other people with similar problems but I haven't seen a defenate solution for this one. The pt it was overheating and I changed the head gasket and cut the head. It drove for about 2 weeks then wouldn't start.I am not getting a injector pulse when the can sensor is plunged in. I changed the can several times and crank also checked it with a multimeter. The timing lines up perfectly or do u have a diagram for the correct timing as some people have it off a cupple degree. Other people are saying its the timing do u have a solution for me.