Nissan - Pathfinder :: 1994 - Intermittent Inability To Start

My 1994 Nissan Pathfinder will intermittently not start. When I get in the car and turn the ignition, the dash board lights will light up as usual, I can hear the starter solenoid click, but then nothing will happen. The power windows, stereo, headlights and air-conditioning will all work but the motor will not even churn. All I hear is the click. If I get a jump the car will start right up.

This has been going on for over a year. At first it would only happen every few months and I thought that by just disconnecting the positive from the battery and putting it back then it would start. It appeared to be doing so. When it started happening more frequently, I took it my mechanic and each time he would fuss with some wires charge me 20 bucks or not charge me at all and I would be on my way. It would be good for a week or so then once again not starting for me.

After the three times of my regular mechanic not fixing the problem and saying it was fixed I took it to a different mechanic. This man said it was my starter even though it will start with a breeze if you jump it. I went ahead and had him replace it. My car started a few more times but the next day the problem was back. After having gone to two mechanics and them misdiagnosing and me paying for service I didn't need, I borrowed a volt meter and the battery test at 11.5 volts. Some buddies said, that perhaps my battery being 14 years old was putting out enough power to power the cars electronics but not enough to turn the starter over. So I bought a brand new battery. I got four starts off of it before I experienced the problem again.

Another friend thought it might be the alternator not fully charging the battery. I believe we tested it at 12 volts but he said it should be more. Anyway, he and I pulled the alternator took it to be tested and it's fine. While we were removing it though we discovered the belt on the alternator was a little loose so maybe it wasn't charging fully. Anyway, we put it all back together and the car started five or six times, while my more knowledgeable buddy was with me. The next day of course, no start.

I probably did a bunch of stuff I didn't have to do in trying to diagnose this problem but at least I learned a lot more about my car. Anyway, ye wise car sages, What do you think is wrong with my old car, which for the most part has treated me well for all these years? Ignition? a short somewhere? If it's the ignition perhaps you can explain to me why the vehicle will start with a jump.