02 mustang gt 4.6

Driving down highway tonight....gauges go crazy, battery over charges to the point it boiled out the top. Gauges eventually stop being stupid but battery light stayed on until I got somewhere I could pull off. Disconnected hot post to battery, car died. Retsrted and able to make it home. Hosed off all the boiled over acid car was running. Disconnected the battery again...car died....now it will start for like 2 seconds then die. Doesn't matter If give throttle or not, it will not stay running. Can not see any loose wires or anything to cause it. Do have fuel at fuel rail. A couple days previous wife had it die on her at a stop sign....theft kept flashing and shut it down to a crank no start. She was able to start it with the key fob, insert key, turn on ignition and no more problems.

 

Disconnecting the battery and the car dies? Yeah, that’s normal. You can run a car without an alternator until the battery dies but without the battery you, there’s no ground. Btw, pulling the battery cable while running can fubar your electronics.

have the alternator tested, sounds like it’s overcharging.

between that and pulling the cables while the car was running most likely damaged a sensor or popped a fuse or two.

 

Get a new battery, throw it in , start the car, check the running DC voltage. If that battery boiled out the top its junk. In fact it has probably been junk for a while now, an internal short in the battery will cause it to discharge rapidly and the PCM will order the voltage regulator to max charge it. Usually it burns up the alternator as well, I had one that just all of a sudden the alternator starting humming loudly, every thing flickered the AC got warm then it died. Put a new alternator on and with in 5 min of driving I started to hear a loud humming from the alt, 5 min later the car died. New battery and replacement alt and it was perfect, the battery tested for an internal short.