Please help. My daughters boyfriend has an 03 Duramax. He came over and it ran fine other then once in awhile he would have to press the primer before it would start. This time he went to leave and it wouldn't start even after priming it several times. He let it sit for almost a year then we changed the injection pump cp3 because he thought that was the problem. Still no start. The filter head componet is also new so the o-rings should not be an issue. After installing the new used pump we are unable to get it to start. Primed it several times even cracked open a injector line and it had a lot of pressure and fuel in the injector line. Were lost please help.