Recently, right after my alternator belt snapped and after getting it fixed, I've been having this weird electrical problem where every time the car requires some electricity from the battery the battery seems to just drop in voltage and the HUD lights go dark/turn off. The same happens when I push the brakes, turn on my radio, turn on the headlights, etc. The car can barely start because the starter can't even turn due to the voltage drop.

I tried charging/swapping the battery, jump starting the car, swapping between ecu's, and checked most fuses I can find. Everything seems to be fine but I still have the problem. I think it might be a ground, but I don't really know where to start. If anyone has/had the same problem, a direction or answer would help out a lot .

 

Might want to check all your large gauge wires between alt/bat/body, mainly the negative battery to chassis wire.

 

What is the voltmeter saying when this is happening?

Sounds like the alt is failing.

 

I'll check the alternator, but since the engine can't turn on in the first place even with a fully charged battery then there is something wrong. I also had to push start the car once to move it from a far location to my house. The car works after push starting it, but once shut it off the same electrical problems happen. I'll check the alternator and all the grounds when I have the chance none the less.

The voltmeter says 12v when I just put the car to the on position, and when I try to start it drops below 8v on the meter. However when I got the car started, it was normal at 14v while running. If I keep trying to start the car, the battery then loses all it's energy without even turning the engine.

 

def sounds like faulty alternator

 

How do I go out at checking the alternator? I have a multimeter at hand, I just need to know how.

 

Not a fully charged battery if it is dropping down below 8 volts when cranking. Its pretty tough to start a FC without at least 8.5 volts.