I had the car running and went to take the battery out so I could charge my Blazers battery. But when I unhooked the battery the car shut off. WHY? I thought that if the car is running it will stay running when you take the battery out.

wow, doing that would never cross my mind. Well considering the battery powers the computer, fuel pump, and many other essential things that power the car is why it shut off

yeah, pretty much everything is powered by the battery these days. if it was carbureted, then it could probably have kept running. you have some big balls to be touching the battery while its running. isnt there like ~500 amps running threw there?

I don't know how all this stuff works, but on my Tracker I pulled the battery all the time and it stayed running. I think it does on the Blazer too.

Thought it was kinda odd that the Bonneville didn't.

idk if its just a myth, but ive always been told that pulling the cable on any fuel inj car is a BIG no no. it can damage electronics. not likely, but can.

and there are many safer ways to test ur alt anyway

I think it was because you lost the negative connection of the battery.

Definitely, NEVER do that again. Thats not good for it at all.

In what ways? I've seen this done before and never seemed to harm anything. Namely early 90s F-bodies.

well, I might be a little bit redeck, but I have done this soo many times it isn't even funny. Yes on fuel injected cars also.

I am not recommending anyone else do it, because there is a possibility of damage though.


I think that the car should stay running, in my experiences, this is sort of a redneck way to check to see if the alternater is working. ( disconnect the battery... car stays running = alt is good, car dies = alt is bad ) This may not be the case here though, so I wouldn't be worried. If the battery always stays charged, I wouldn't worry about it at all.

I wouldn't recommend disconnecting the battery while the engine is running on a modern car with its complex electronics. The alternator puts out an AC or alternating current. The diodes in the alternator changes it to pulsating DC. Both of those can cause problems with the electronics in the car. The battery is used like a huge capacitor to smooth out the pulses to give a nice DC voltage.