Is it bad on LM to weld on the car?

[Anonymous_User]

Yesterday, after finishing the tranny swap in my nieces car, I needed to relax a bit. So, I pulled the 'tona in the garage to finish welding up my IC mounts. I pulled the battery out, amongst other items, and did some welding on the radiator support. When I got it all back together, the car wouldn't start. Then I noticed there was NO check engine light EVER. Well, I've seen that before, so I plugged in my spare LM and drove the car home.

This was my last socketed LM, so now I have to do some soldering.

Should I have removed the LM before welding? Or was it just a coincidence that it happened at that time?

[glhs875]

Yesterday, after finishing the tranny swap in my nieces car, I needed to relax a bit. So, I pulled the 'tona in the garage to finish welding up my IC mounts. I pulled the battery out, amongst other items, and did some welding on the radiator support. When I got it all back together, the car wouldn't start. Then I noticed there was NO check engine light EVER. Well, I've seen that before, so I plugged in my spare LM and drove the car home.

This was my last socketed LM, so now I have to do some soldering.

Should I have removed the LM before welding? Or was it just a coincidence that it happened at that time?

I feel like it just happened on it's own. If the ground is removed from the battery that should keep voltage spikes from the logic. But then again anything is possible!

[GLHS592]

I always remove any computers from my car when I weld on the car itself. I had a logic module problem with my car after I welded some things.

[glhs875]

I always remove any computers from my car when I weld on the car itself. I had a logic module problem with my car after I welded some things.

That's not a bad idea.

[BadAssPerformance]

I usually just disconnect the battery.. no problems so far.

[86Shelby]

I would simply take the 3 minutes to disconnect it before welding to avoid the possiblity of any issues.

[Aries_Turbo]

yeah I had a LM go bad soon after I welded a bobble strut tab to the car. it takes a few sec to remove the connectors for the LM/PM and pull the LM.

Brian

[turbovanman²]

I have heard of it happening but its never happened to me yet, knock on wood. Maybe it was fragile and the welding was the last straw?

[BadAssPerformance]

I think it also depends on how good of a ground your welder has to the metal being welded (both pieces) and how close it is to the area being welded as well.

[Anonymous_User]

Ground clamp was less than a foot from where I was welding. Area the clamp was attached to was ground clean. I guess it's just my luck. Next time I will definitely remove the connectors on the LM. Should have done it this time, I guess, especially since the kick panel wasn't covering it - just had to reach up and pop the two connectors off.

*sigh*

This car hates me.

[lametec]

I don't see how disconnecting the battery would help one way or another.. The LM is still connected to all the wiring on the car. If anything, leaving the battery connected should act as a "filter", making the LM less likely to fry.

I say disconnect the LM/PM, though.

[Anonymous_User]

I didn't remove the battery for the sole purpose of welding. It was removed because my son was fiddling with the stereo wiring and I didn't want him shorting anything out.

I also do not see how removing the battery or leaving it in for that matter, would make any difference.

[BadAssPerformance]

Step 1 in any underhood proceedure is to removed the battery connections. This way there is no power going thru the wires. With respect to welding it is good to have it disconnected in case and some wires end up getting grounded and shorted out due to the welding. Of course if this happens it will be a mess when the battery is re-connected, however it will be easier to deal with while not welding. Disconnecting the battery also opens the loop on most circuits that current can travel thru while welding.

[ShadowFromHell]

I doubt it. I work in a body shop and have welded on hundreds of cars without a single problem with the computer. Years ago it was thought you had to remove the ground wire on the batt but ICAR doesnt even require you to do that anymore.

[overlordsshadow]

Not sure if LM's and the firewall computers are in the same boat on this but never had a problem with my comps. I Either disconnect or use a Zap Happy. The Zap Happy basically just connects the pos and neg together and keeps the circuit safe from the weld arcs without having to disconnect.

[Warren Stramer]

You didnt say what type of welding setup you were using, I wouldnt get concerned about DC tig or mig, slightly concerned about AC mig, BUT if you were welding high frq. TIG you could knock out electronic stuff in the next county. Well maybe a little stretch but High Frequency TIG is nasty on electronics because of the RF and electromagnetic pulse it emits.
I have a friend that builds race cars for a living and his shop is located next to a buisness comlplex, when ever he would weld the buisnesses would complain that he made their computer equip go bezerk. After wrecking some of their stuff he had to start working at night when they had their stuff shut off.

[BadAssPerformance]

Warren, do you know what kind (brand/size) of welder that was? Sounds like the transformer it was powered thru was not doint its job.

[Warren Stramer]

Jason, No I dont know for sure but I think it is a Miller, I know miller instuction manuals are anal about grounding and RF cautions around electronics, and so is my HTP manual, but only in high freq. AC mode.

[turbovanman²]

You didnt say what type of welding setup you were using, I wouldnt get concerned about DC tig or mig, slightly concerned about AC mig, BUT if you were welding high frq. TIG you could knock out electronic stuff in the next county. Well maybe a little stretch but High Frequency TIG is nasty on electronics because of the RF and electromagnetic pulse it emits.
I have a friend that builds race cars for a living and his shop is located next to a buisness comlplex, when ever he would weld the buisnesses would complain that he made their computer equip go bezerk. After wrecking some of their stuff he had to start working at night when they had their stuff shut off.

Thats great info Warren,

[BadAssPerformance]

Jason, No I dont know for sure but I think it is a Miller, I know miller instuction manuals are anal about grounding and RF cautions around electronics, and so is my HTP manual, but only in high freq. AC mode.

Wow, usually Miller welders are pretty decently internally filtered, but like you said, Hi freq and A/C can mess stuff up for sure.