Welding on a BMW (or any modern car)
 

Any time I or someone else has done any welding on my 911, we remove the DME completely from the car to be safe.

So that got me thinking - what if you had to weld on a modern car like my E90. NFW you can remove the electronics like you can in my 911. Any one done this? No big deal or is there something special you need to do before hooking the car up to the welder?

I almost had to resort to the old "weld a nut to the transmission fill plug" because I'm a f**king gorilla and stripped the 8mm hex out. I got the fill plug off with an air chisel, but it got me thinking about the welding issue.

I fried several of the 964 electronic components by just using my big charger "hot start" option for countering a dead battery. Can't believe error-ing on the side of caution for actions like this isnt prudent. Though I've seen auto body shops weld on chassis without even disconnecting the battery. Maybe like many things "it depends."

Keep the work clamp clean, tght well grounded to the base metal being welded and close to the work and worry little IMO. For example the old rule of thumb to disconnect the positive term is not based on any real protection value. Many people do only that and weld away thinking that the lack of damage was due to their precautions. The electrons want to go from work to clamp or vice verse not wander off where they meet with resistance or lack the capacity to cope.

Doing some. AC TIG with high frequency? You might want to shied the more sensitive stuff.

I always disconnect/remove the ECU when welding on the car (as did BimmerWorld when they installed my cages in the E46 and E92). Not sure if it could have been fried if I didn't, but they're expensive and it's a precaution that's easy enough to do.

That seems to make sense but on a modern car with multiple ecu's/control modules (think benz) it's not very practical IMO.

Most everything is connected with ground straps so to me it's disconnect all or nothing. Nothing usually wins out.

I will see what the Manufactures requirements are for welding. I can ask the body shop manu cert holding techs.

Time to upgrade to a digital welder. Don't forget the anti-virus.

OK the word from I-car, MB and Audi. Disconnect the battery. No welding within 12 inches of any wire. No removal of ECUs mentioned.

Thanks for the follow up. Now to figure out the proper method of battery disco. :)

Awesome - exactly what I was looking for. Thanks!