try cleaning the battery terminals and clamps and make sure they are tight. check for voltage drop from the battery to the clamp, then the cable, and then were it meets some other parts down the line.. bet it is weak someplace along the line and that is why its weak or no start......
also check and see how much amps are being pulled by the starter... or check to see what the voltage is to the battery when cranking, should be at least 9 volts, if you get a jump then you add 12 volts from the other car and your 3 or 4 volts and get 16 volts, then devide that by
two and you get 8 volts and that is why it is not starting or is starting it you have 6 volts and you put 12 plus volts on the jumper car that gives you 6 + 12 = 18 /2 =
9 volts and you can start the car.....
