Robot Jox 3 ????

Hey help me with that. I also remember Robot Jox from chilhood. And I remember three movies. The first one was Robot Jox ( I remembred the title a while ago while searching for it on the net) the second was a "Robot movie with a giant Scorpion robot" that was Robot Jox 2 in europe. BUT there was a third movie. And I had it in my mind as a robot Jox sequel, i do remember it has a Robot Jox writed on it's cover cause I telled my mom to rent "another robot movie":). The movie started as some guy drove a chopper thrue a desert, he reached some kind of base and there were giant robot scraps around it. The whole movie was a bad horror where a bunch of people were trying to kill a cyborg that was hiding amongs them and killing them for uknown reason.
I remember there was some talk about great Robot wars long ago. And the only reference to Robot Jox was that when they killed the cyborg, they used an old giant robot. I remember being very dissapointed after seeing that becouse i ecspected something like the first two movies, and also a bit confused cause the movie was a bit brutal and my young fragile mind couldn't take it:). I'm sure that this was also a Robot Jox movie. Anybody knows anythinf about that??

ps. Another scene that i remember is that this mean cyborg pulled a fat guys arm out, the arm was already hurt from some accident.