Welding & the ECU

[waad_uk]

Hi Guys, I have to weld a small bracket on my tow bar (which is on the car) Is there any problem welding whilst the ECU is connected, or does it have to be removed?

[GT500]

Never had an issue, Mig or tig. I don't bother disconecting anything..
you could play it safe and use a oxy/accetelene torch, then oops i set the car of fire!

Just make sure the earth cable is on a good place and near to the weld.

[repo]

It is pretty easy to take off negative battery terminal just in case.

I always unplug the ecu, as I have fried a couple of ignition amps when welding an exhaust pipe tip. First time I thought it was a coincidence, after second time I am pretty sure.

Also, unplugging the ecu is not that bad of a task, when comparing to the pain of finding a new one, and unplugging after that.

[S2central.net]

Your definitely should disconnect battery when doing any welding - its for the health of your ECU, ABS, Airbag and any other sensitive devices !


Paul

[dubmeister]

welding can kill the ecu, alternator and any other sensitive electrical parts, it can also cause very strange and annoying electrical problems which can be a nightmare to trace- as can jump starting the car- mk2 golf gtis were bad for this- the ecu messed up and opened all the injectors when the ignition was on- you try to start a car that has all the bores full of fuel!!
If in any doubt disconnect the battery- one 10mm nut can save you a lot of hassle!!

[waad_uk]

Cheers chaps, battery will be disconnected!

[BrianSmith_S2]

when i had my bypass pipes weleded recently at longlife basingstoke they spent ages looking for the battery in the engine bay....

after a while i pointed them in the direction of the rear seat.

not sure if they only disconnected it, but they also connected a box (suppression system) across the terminals to prevent spikes.

Brian

[s2dude]

Cheers chaps, battery will be disconnected!

You need to disconnect the ECU as well as the battery from what I was told

[S2central.net]

That is what I would do actually - to be sure to be sure - and with the ABS controller actually !

[s2dude]

That is what I would do actually - to be sure to be sure - and with the ABS controller actually !

Agreed Paul.
Voltage spikes big enough to damage ECU's etc are apparently possible even with the battery disconnected
Worth doing just in case considering how easy it is!

[waad_uk]

No problem, I will unplug those as well. Just out of curiosity whats the item under the rear seat by the battery that has a connector similar to that of the ecu? Is that part of the ABS?

[s2dude]

No problem, I will unplug those as well. Just out of curiosity whats the item under the rear seat by the battery that has a connector similar to that of the ecu? Is that part of the ABS?

ABS ECU Connector

[waad_uk]

Great, cheers again
I will get stuck in tommorrow...

[GT500]

Very strange that I must have welded at least 50 cars and never had a problem!
Perhaps its down to the make of welding machine.

[S2central.net]

That or you have injected spurious eletrical gremlins into 50 cars that can't be traced to a welding episode

No seriously I think this is just a matter of 'best practise' really - maybe the first electrical welding machines were really bad in this regard and modern stuff is OK.

Better safe than sorry I say.

There is also a risk of damage to the ABS controller when the car is in a paint drying oven - strange but true - there is specific mention of this in the OFRM that the ABS controller gets damaged by prolonged high temperature !


Paul