My 1984 jimmy started idling wired and then died. I then changed the fuel filter base from a standyne base to and aftermarket fuel base with a screw on filter/separator because I knew I had a problem there because of diesel slowly leaking from the back of it. bled out the injectors and still will not start. I also installed new glow plugs because I had planned to and this was the best time. Will not start. What I’ve noticed is that the fuel cap has a huge amount of pressure on it when I try to take it off. I mean like I have to use a large channel lock pliers to get it of. I know this can’t be right so this I think is a clue . the injection pump was change about 3 years ago but has just been driven around the property an not had any real miles put on it so it is fairly new. Any help or thoughts?