Just put in a new rad support and fenders. I thought I put everything back like it was. However, when I touch the pos side of the battery post, it sparks, not a little spark, a fairly big one. Where do I even begin to track this down? Is it a grounded wire where it should not be? Help...

Do you have that positive junction block that attaches to the radiator support grounded?

Yes sir, I do. I have checked and rechecked all the wiring. Everything "looks" ok. This was an entire engine swap also from a 307 to a 350 also converting from points to HEI. I have also replaced the original alt with an exact replica new one. Could a bad starter do this? I replaced the battery cables with new ones also. The pos cable on the starter was not grounded on anything either.

I have seen sparks before when there is something to run a load, so as soon as you get the terminal near, it arcs in order to power something. Could this be it?

If you leave it on does it smoke and get mad? If it isnt the load than you must have a power touching the body somewhere, and when you connect the pos you get sparks.

Do you have that positive junction block that attaches to the radiator support grounded?

Yes sir, I do.

There's your short. If the positive junction block is grounded, it's gonna spark when you put power to it.

Oops. I read his reply wrong. No, it is not grounded.

I've had this happen to me before. I put a starter in a Toyota and I couldn't hook the battery back up. It's like your battery switches polarity. Try a different, good battery just for grins. If that doesn't do it, and everything is right, then your over looking something.

Disconnect the positive wire from the battery to the positive junction block and attach battery cable. if it still arcs then you need to check the starter and ignition wires. If it doesn't arc then check with voltage meter for continuity between body and positive junction block. You may have pinched a wire when you installed your radiator support.

Just put in a new rad support and fenders. I thought I put everything back like it was. However, when I touch the pos side of the battery post, it sparks, not a little spark, a fairly big one. Where do I even begin to track this down? Is it a grounded wire where it should not be? Help...
Normally we would talk in milli amp parasitics and use a dvom to diagnose.Your description describes a shorted B+ to ground.Connect a 12 volt test light in series between the battery positive post and cable end.The test light will be illuminated and will allow you to disconnect components and bus bars at will while observing the test light.When the test light turns off....you have located your short to ground.

Normally we would talk in milli amp parasitics and use a dvom to diagnose.Your description describes a shorted B+ to ground.Connect a 12 volt test light in series between the battery positive post and cable end.The test light will be illuminated and will allow you to disconnect components and bus bars at will while observing the test light.When the test light turns off....you have located your short to ground.


I concur, this is the easiest way to find a short to ground.