did some welding now no start condition.

67Dart273 said

Sorry no. Put this in your mind

You absent minded clamp the welder ground to the transmission.

Bear in mind that most STOCK cars have a poor (small) ground between the block and body, and the body is what you are welding on

So the "ground path" is

welding clamp..........transmission.......engine block........

.........and whatever it can find to the body

no 10 jumper wire from battery neg to body?

block to firewall bonding straps, small, 1 or 2 ea LOL

automatic, the cooler lines

and so on

NOW picture in your mind WHAT ELSE current might attempt to parallel through...................

Click to expand...

Yep.

In the absence of good grounds, a vehicle will make its own grounds.

Years ago, when my D50 had a Turbo Diesel in it. I had used regular "Gas" version Ground Cables to the Block & Frame and couldn't figure out why the diesel was cranking so slowly. (That was the day I installed 0 and 2 Gauge cables in the truck) I reached under the hood to check the connections at the starter and my arm bumped the Clutch Hydraulic Line (Master to Slave line) and burnt a 1/4" Deep Groove in my arm. The Clutch Hydraulic System was turning into a ground, due to the poor grounds on the truck and had superheated to absurd temperatures in the process.