my 87 rx turbo won't stay running unless I use jump cables. When jump starting it, the car starts and runs, as soon as I disconnect one of the cables, neg, or pos, from the battery, the car dies immediately. I just had my alternator tested at schucks, and it passed. The battery is good, I tested it on my other car.

 

anyone know why its not charging my battery???

that is a pretty good question.. All i can do is give you a place to start looking: the fusible link block, behind the battery on the drivers side strut tower.

sounds like a poor ground. the alternator is supposed to be connected to the battery at all times too.

check the hot wire on the alt, i had to replace mine last year. its not hard to do, just make sure it isnt burned or heavily corroded. just cut it back past any damamge and splice in new wire, make sure you use what i think they call "underhood weather tite" connectors, they work like a normal crimp on splice until you hit em witha lighter, then they work like srink wrap witha gle mixed in. i havent had any chargine problems since.

First check the fusible links and the fuses for a problem. If those are fine then check to see if the charge warning light comes on when the key is turned to the 'RUN' position. If the light doesn't turn on then make sure the bulb is good. If the bulb is ok then start the engine and check the voltages on the wires tied to the alternator. They all should be near the battery voltage. If a line is low then that lead needs to be checked as to why it is. If you have a white/red wire, I think that one leads to the warning light.

 

One thing to note. It is not a good idea to run the alternator without it being tied to the battery. The battery helps reduce noise pulses from the alternator which can possibly damage electronic circuits. A lot of folks do this though and get away with it.