Help, electrical question!!

[EXTRPR50]

Hey all, I am buying a 95 GT , all stock with aode.

It would not start, so i checked the starter, it was bad, so i replaced it. I checked the altrnator, it is good, and the battery is good but needs a charge they said at pep boys.

So when I hook up batt cables to the car it starts and runs, until I pull the neg cable off and the tach. dies. Then the car dies.

If a batt doesnt have a good charge, would it make the car die? I thought the alt took over after it was started.....

Any thoughts appreciated, I'd really liket to drive it one day, thanx, all.

 

[jrichker]

If the battery is weak, the alternator will not put out enough power to keep the car running. The alternator pulls power from the battery to energize the field windings. They create the magnetic field that is part of the process that generates output power from the alternator.

 

[autoXr1]

At least with a vehicle that is managed with a ECU, poor grounding can lead to all sorts of erratic behavior. That said, removing the negative battery cable and interrupting the electron pathway, it is conceivable that the vehicle wouldn't run regardless of battery charge. Someone please check me on this, but I am not sure that your battery cable "test" is the correct one to perform to assess your situation.

 

[HISSIN50]

if you are 'buying it' why are you doing all of this? im just curious.
the tach dying first is weird, isnt it Joe? would that suggest the coil is being funky?

one can bench test the alternator.

good luck.

 

[EXTRPR50]

I wasnt trying to test anything, I was trying to get it working.

Anyway, the car is being basically given to me for 1k, it's from a friend who is pretty good off.

I just need to get it working thanx...