I have an 84, and mine only opens if you turn it to the left. I put the key in, turn it about 110=B0 to the left-counter clockwise until it stops. At thsi point it seems that i has no worked because nothing has happened. Then I press the button in. Still nothing. However, if you then try to pull up on the trim around the trunk lid, while holding the button in, it will lift up. I don't know if that is by design, or if there is a spring that would pop it open that has become weak, or what, but that is how mine works. Try pushing that button in and lifting.
To expand on what tiger said about the engine not shutting off. These cars run lots of things on vacuum including power locks and climate control. The engine uses a vacuum actuated diaphragm doohicky to push on a linkage attached to the injector pump that shuts off the flow of fuel. Your problem is either that that part has gone bad, or more likely that you don't have vacuum going to it from either a leak somewhere else, or because the vacuum line going to it has come off. search this list for info on troubleshooting that. There are two orangeish/brownish vacuum lines that go into the firweall. One attaches to the rest of the harness, the other to this part in question. get a vacuum tester and figure out what is going on.
Glow plugs only warm up the engine prior to and shortly after startup, and would have nothing to do with it refusing to shut off.
Good luck,
Bill