A word of advice about ground straps, click and clack and EGT sensors.
 

This weekend I had the trans out of the w124 to replace the clutch. Well I got it out Friday night and came back Sat to finish it up. Click and Clack, the Tappet Brothers, were on the radio but my fancy HD radio in the w123 kept fading out. SOOOOO. I tried to turn on the radio in the w124.

It came on but suddenly I saw a large quantity of smoke and smelled ozone. WTF I said and went running for the extinguisher. Seeing no flame I waited for the smoke to clear. Apparently lacking a ground strap, the glow plug system picked the shortest route to ground, which apparently was the metal sheath on the EGR probe.

Just a word of caution, when you unhook that battery to do work on the car, leave it unhooked until you are done, no matter how much you want to enjoy in hearing about the misery and tribulations of other car owners....

Click and Clack are my heroes...
 

Benn listening to them when I can for about 20 years... Thanks for the heads up. That's probably something I would have tried in the same circumstances...:eek:

Lol, you need to call in with this story, thats something they would probably love as a cautionary tale!

My 9 yr old keeps saying "let's call click & clack" every time I talk about fixing the SD or 78Z.

Yep. When those electrons wont a ground they're pretty determined to get there.

I've heard of people burning up clutch cables and speedometer cables that way, on other cars. And radio transceivers...in amateur radio installations it's common to wire both the positive and negative connections directly to the battery, to minimize noise pickup. If the battery-to-chassis ground strap falls off, it's possible for the starter to find a new ground path through the radio's negative power lead and the radio chassis. It's common to fuse both the positive and negative wires, to protect the radio from this scenario.

"Sneak circuits" like this will drive you crazy, sometimes.