1991 cherokee Laredo 4x4. So I'm trying to finish up my engine swap with a completely rebuilt 4.0 by a local engine shop. I'm at the point where I'm hooking up the transmission lines back to the transmission on the passengers side(i pulled the trans and TC cause i was doing a IRO long arm at the same time). I noticed a pinch in my hand when I first put the rear line in. When I went to do the front and was inserting it into the coupler I saw a visible electrical spark between the connector and the tip of the line. I had the battery connected just to have some music playing and did not think there was an electrical hazard connecting transmission lines?!?!? I checked the battery terminals and grounds out of the battery and I dont see any shorts. The radio kept playing like nothing happened. I checked to make sure the lines weren't resting on any wires and they were clear of anything electrical. Anyone heard or had this happen to them before??? Needless to say I disconnected the neg terminal and put the line in but haven't hooked the battery terminal back up.

 

Got all the ground connections to the engine hooked up yet?

 

Probably just a fluke, but! Just in case it's not, I suggest you get a test light between the negative terminal of the battery and the negative cable terminal. Make sure the key is out and the doors are closed. The light should not light. If it does.... sumthin's wrong! Proceed with caution!

If you get a bright light, I suggest making that connection again with a fused lead. No test light, just a fuse holder with a fuse in it, say, 5 amps. If it blows, you know you have a problem. If not, go ahead and connect the terminal, but be ready to yank it off of there.

 

So i had not connected any grounds yet. I had just run the neg battery cable down to a bolt on the frame but the engine ground was not hooked up. I was thinking about it last night, is it possible the engine is isolated and I basically grounded it with the trans lines. Cause they were resting on some of the front suspension and would have then been grounded. I replaced my engine ground strap last night and grounded batt->fram->engine as well as the rear head to firewall strap.

 

Yes. That was exactly what I was thinking when I asked if you'd hooked up the ground to the engine yet. Although 12-volts shouldn't have much bite to it.

 

Haha it wasn't much of a bite! It felt like I just caught a nerve or hit my funny bone in my arm. So I reconnected grounds. Actually I made all new bat to frame, fram to engine and firewall to engine grounds out of some 1/0 wire i had from when i did my f250 a few years back. Went to connect the trans lines and no spark! Thanks yall.