I always pull my negatives as a precaution not to fry my pcm. Am I wasting my time doing this?

 

i wouldn't think so. to have all those harmonics and transient voltages wandering around is awful risky.

 

I am no expert, but I have heard that it does not really matter. I know of plenty of people that have welded on their trucks with the cables on the battery. My truck has been welded on (well, the flatbed) without removing the neg cable and everything seems to be fine. I guess there is a slight chance that anything could happen. Maybe someone else knows for sure.

 

I used to weld on rigs without disconnecting the batteries all the time until welding on the tailgate of a Toyota I fried the $800 computer.
Easy enough to play it safe.

 

I usually pull the battery cables. It's better to play it safe. I've welded exhaust systems on without removing the cables, but that's about it.

 

I always pull the cables to be safe.

 

At work and when im welding on my truck at work. We always use like a voltage spike regulator thing. It hooks onto the positive and negative terminals and glows a green light. If a spike goes through a red light will come on and it will sound and alarm.

 

Then what?

 

The likelihood of damage depends on the type of welding and the circuit path. DC stick and MIG are relatively low voltage and likely not to do any damage. AC stick, square-wave TIG, or TIG with an HF start could very likely do some damage to on board electronics.

 

Even if you pull the battery grounds, there are many other grounds throughout the engine bay, it is still grounded. Just put your welding ground as close to where you are welding as possible.

 

Then you order a new ECU.

 

Get the ground as close to the weld site as you can. If you weld on the exhaust system, ground to the exhaust, no the frame. If welding on the frame, ground to the frame, not the body.

 

I welded up my whole front bumper on my truck without disconnecting the batts. Is it safe? I dunno, everything still works

 

If I am going to weld on anything I always disconnect the cables. For no longer than it takes to unhook them and for what electronics cost it is just easier in the long run. I am going through a John Deere Techinician training program right now and they teach us that if we weld on something unhook the cables. I figure that if there teaching that I probably oughta do it because theres a reason for it. While your at it you might as well clean them if you got them off anyway.

 

lol You know i'm not too sure, i've never had it gone off. If I remember the next time i'm at work I will see how it works...