I just picked up an O/T car and am having some issues that I'm hoping to get direction for. I was told it was running with a very high idle and that he didn't want to mess with it as he was only out here for a job. I towed the car home and thought I'd give a go at figuring out what is going on. By now the battery was dead so I thought I'd try jump starting it. I hooked up the positive cables then the first ground and then when I went to connect the other ground I got a large spark. Didn't think too much about it until I noticed the cable ends were heating up quite a bit. I immediately unhooked everything and haven't touched it since. I was afraid to try throwing in a new battery until I could get some answers as to what might be going on. I was wondering if the alternator could have developed an internal ground. I figure it's gotta be more significant than some little wire or I'd have seen some rapidly melting wires. Looking for help or direct me to a site where ki might find help since the car isn't HAMB friendly.
Would be worth disconnecting one of the terminals on the battery of the car you're jumping to, and see whether the same thing happens when you connect to the battery with the car's wiring out of circuit. It's quite rare with modern car batteries to have the internal plates go short circuit; but it only takes a few moments to check for it.
Are you using good heavy jumper cables or the crappy shoestring ones you get for 10 bucks on sale. I have had the cheapy sets do that even when everything was ok other than a dead battery Sent from my LGL52VL using The H.A.M.B. mobile app
Also are you sure of your polarity? I have a pickup with a red negative and a black positive cable because that was all the parts store had when they had to be changed by the previous owner Sent from my LGL52VL using The H.A.M.B. mobile app
It's not unusual to get a spark when connecting jumper cables to a dead battery, and not unusual to get heat from a jumper cable due to poor connections or oxidation at the terminals, especially if the dead battery is drawing a lot of current or you try to start the car too soon after connecting jumper cables. I'd disconnect the original battery and try to charge it up, or replace it with a good battery. Then reconnect and see if there's a spark as the terminals are connected. When a car is completely shut off, there should be zero closed circuits (except for clocks, stereo memory, or computer, if applicable). If there's a spark that will tell you if the car has a short or a closed circuit that's drawing current. If there's a short or other draw, to prevent a meltdown (or fire) simply put a source of resistance (like a light bulb) between the battery positive terminal and the positive cable terminal. The bulb will light, indicating a closed (or short) circuit, then trace the lines (start by pulling fuses one at a time) until the bulb goes out.
I would try disconnecting the battery and charging it up first. Or, there is a procedure to check for short circuits if you want to take the trouble. Disconnect battery, shut off everything in the car, connect battery through a test light or ammeter. In other words leave the pos cable on, disconnect the ground, and connect one end of the test light to the battery, the other end to the ground. If the test light lights up you have a short. If you use an ammeter you can tell how big a short. Go around pulling fuses to find out which circuit the short is in. Or,it could be, the battery is dead and that is the big current draw. If you do have a short don't leave the battery connected, the short will kill it.
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