fried my battery........

[RogerZ 280]

Ok .. lets get this out of the way. :nervous:I reversed my cables on a jump of a 1983 280zx turbo i was picking up. Ive found a 'donor' car that ive replaced my fused unit next to the battery( the one in the little box with three plugs), engine turned but no start. tried too many times, battery died.

ok, lets see what else i can ruin. replaced the battery, replaced all 6 plugs, and then the engine just made a 'thunk' sound when i tried to start it. so, i went to the donor and got the starter thinking that was now the problem. R and R the starter, turned the key and.... thunk. Spoke to a mechanic and he thought the engine might have siezed by fluids backed up due to the number of start attempts. so........... i take my 29m and hand turn the engine to try to free it. it turns, put the key in, turn it . nada. How many relays, capacitors, fuses, small rural towns, might i have fried, and how do i fix this?

note. Im not new to 280s, jsut the electrical problems. thanks

[Blue Meanie]

Yikes! No real input on how to fix it, but yikes!

Hey there is a really old, really good restaurant in Decatur Alabama, really good expensive food right off main street. I used to go there when I worked at Regions. It's also the home of Big Bob Gibson's BBQ. Ever make it over?

[RogerZ]

If it doesn't even turn over god only knows. I'd disconnect the fuel pump and hot wire the starter just to see if you get a crank. load test the battery. make sure all battery cables are clean tight and corrosion free. If you didn't fry the ecu you should get something The engine should at least turn over

[Matches]

Maybe there is not enough juice from the battery to move the engine. It spins freely by hand, so the engine is not stuck.

Are you hearing the starter solinoid click over? Check the fuse box to be sure there is nothing melted. Could just need the extra juice from a jump to get it to spin again.

Or, look over the main power wires and look for signs of damage. Melted insulation and whatnot.

[RogerZ 280]

thanks for those. ill check them all out.

[AnthonyG]

I had a similiar issue in a different car. Jumpered it wrong to jump start it too. actually blew a relay. the tow guy tested it by shorting across terminals for the relay so it was closed as it was supposed to be, and it started. apparently once it was started it didnt need the jumper either. it would prove it was the issue. there are those more knowlegable that could suggest which relay it might be...

(I'm not an expert, just a collection of interesting experiences)