stu.p

new prob guys
car ticking over fine for ages!!drives ok for a few miles but battery light seems to be on all the time,,re-done the earth on my starter to gearbox,still the same drives ok for a few miles then have to keep the revs well up to keep the car ticking over then it cuts out after it coughing and banging at revs.jump started car,started ok then wants to cut out straight away again,,light on dash seem to go dim aswell...seems like something draining the battery or alternator wiring incorrect???..not sure though!..any ideas???
p.s engine just been re-fitted after rebuild

dholling13

After testing the battery, which I am sure you did, check your fuse panel for any blown fuses. Then I would start checking ground wires to the battery and alternator. Sometimes the hood, door, and glove compartment switches can go bad and drain your battery.

cobalt

In simple terms the battery is only needed to start the car after it is started the alternator takes over and runs everything and recharges the battery. If it dies after being started it sounds like either the alternator or voltage regulator could be failing. Start the car and disconnect the negative terminal if the car dies it is your alternator. If not use a multimeter to test voltage. If voltage is not constant, odds are it is your voltage regulator and or you have glazing of the brushes or the brushes are worn.

Usually when the tach starts jumping it is due too very low voltage or erratic voltage.