I have an underhood welding system on our rockcrawling jeep and we've done a lot of welding repairs over the years on freinds vehicles or on our own. Whenever possible we always try and remove the part to be welded from the vehicle, but at times this is not always possible, especially when we are welding on our own vehicle that is running the welder. My brother bought me a neat device from the Snap-On guy for christmas years back; it's a 12 volt surge protector that clips onto the battery terminals and helps to protect against voltage surges caused by jump starting, welding and plasma cutting operations. It is Blue Point part number YA100. A neat, compact little tool with a LED to let you know if it's hooked up correctly. All I can say is that in about ten years of welding on various vehicles out on the trail with it we haven't had any electrical problems that I can contribute to the welding so far, could be that we are just lucky, or perhaps the little bugger is doing it's job. So maybe it'll help you with your situation.
Chaikwa,
What you are worried about is pretty interesting, and I must admit that if it is what I am thinking it is, then you are playing by a whole new set of rules. First off, let me say that if I am correct, what is being experienced is a sort of electromagnetic pulse. If I am wrong, someone please excuse my ignorance, as it will not be the first time, and if it's the last then I'm doomed to never learn anything new. EMP is a whole different ballgame because it does not depend on conduction to exist like you would think of normal electricity, but more on space. EMPs radiated (through thin air) hit the cables then surge down the line as albeit normal but small voltages (it would take a large incident to produce anything with high enough voltage to fry simple 12V systems) until they die out. My pickup is a '91, and is the newest vehicle I have ever owned, and therefore, does not have very much that runs off anything other than 12 volts. Newer pickups, however, use tiny voltages to relay info to processors such as in throttle controls (gimme a carburetor or simple diesel injection anyday rather than a computer!). This is why your pickup is succeptible, again, if EMPs are what is to blame.
Now, for the solution: I know only of one form of surge protector for such a case, though there may be more. It involves a light-emitting diode and a light sensitive receptor. As the voltage is pushed through the LED, the light shines into the receptor. However, the receptor can only pickup a certain amount of light, therefore limiting the voltage on the pickup to a maximum amount and you would fry the diode before you fry the computer. Problem is, I don't know if they are available, easy to wire in, or expensive. This one was used on a fairly complex circuit board for use in extreme circumstances, and the unit itself was very expensive.
Anyway, hope that helps and good luck!
G. L.
Hey! Thanks again for the replies!
My truck is a 93 Dodge with the Cummins diesel, hardly new either, but the few electronic parts that ARE on it, are expensive as all heck to replace. That stupid little TPS I mentioned goes for $130.00, so I try anything I can to avoid having to replace stuff like that.
I'm going to see if I can find one of those LED surge suppresors. I KNOW I've seen the things somewhere, I just can't remember where.
Thanks again!
chaikwa.
By -
Date 10-19-2004 04:11
This may sound a little nuts, but here in the corrosion belt, we find a lot of vehicle electronics problems are caused by corroded grounds.
Many GM windshield wiper motors get replaced because of broken or corroded grounds.
Electronics, such as TPS units live in a gasket seperated environment from the main engine ground, and become succeptable to damage for the lack of a good ground.
Many of these problems can be solved by adding grounding jumpers, and chances are the same would apply to welding.
It sounds like the device being described is an opto-isolator. Used to signal one device from another where one contains voltages potentially deadly to the other in case of accidental connection such as might happen if a transistor failed. Without substantial redesign of the vehical electronics I doubt if they are likely to help. Surge protection usually involves a device which will resist the voltage normally present but breaks down and conducts when that voltage is exceeded by much. A zener diode is such a device but the problem is still rather complex since you will need to consider the various systems separately. If this were not so the vehicles battery would absorb the surges itself.
Now for a much simpler idea. Why not fabricate some legs for the table and pull it out of the receiver while you work. An air gap is pretty good isolation. This doesn't address the possibility of electromagnetic transmission however.
Bill
I had a 93 Dodge diesel. In ten years I replaced three of those throttle position sensors also. It had never been welded on or thing done to it the things just go out. I have a friend that had the same problem. Your trouble my have nothing to do with welding.
Gary
Well! It would seem this is an easy enough problem to handle.
Buy a new truck.
;-)By the way. They make Micarta in many sizes and shapes (tubing included). Just in case you were not aware of that.
OK, I admit I ain't the brightest bulb on the tree... what's 'Micarta'?
chaikwa.
Oh drat! Why did you have to go and ask that? Now I got to look it up.
Naw, I just blurt every think I know about it.
I am not sure of the chemistry but, its a dielectric laminated material (fiber I think might even have glass in it). It is not malleable but it is machinable. Usually its brown in color.
Help!
We buy it from a outfit thats supplys Cabnet makers shops.
I have a 2002 GMC 2500 that had welding work done on it. When the work was done, the battery was not disconnected. Final result was a $2200 computer and the welding the brackets voided my waranty. I know these problems exist.
There are thousands of arcs struck every day on the back of welding rigs and mechanics trucks, all without disconnecting anything. I belong to an organization of over a thousand (literally) rig welders and have never heard of any damage to a welding rig that can be attributed to welding current.
I've personally struck an untold number of arcs on the back of a 83 Ford, 91 Dodge/Cummins and 02 Dodge/Cummins.
JTMcC.
All I know is that every time I've welded on the truck, the TPS has fried. The first three times it was under warranty. After the second time, it got me to wondering. So I purposely welded on the work table without disconnecting anything and it fried a third time. Warranty again, mainly because the dealer hadn't figured out what was going on yet I guess. That third time confirmed my suspicions and I've disconnected the battery as well as the TPS wires everytime I weld on the table. Well, ALMOST everytime! I forgot one time due to a busy day and things not going exactly as planned, and the result was another fried TPS... at MY expense this time as the warranty had expired. Needless to say, I haven't forgotten again!
chaikwa.
Chaikwa,
Just another thought, but how much steel is between a direct line to the closest wiring on the pickup and where you are welding? I mean actual steel, not some 24 ga. autobody BS. If you look at any welding bed on a rig, you have a minimum of 4 times the thickness of steel found on fenders (my uncle's amazingly is 3/8"!). Again, this would only apply if EMP was to fault, but its a whole lot harder to reach the wiring for brakes or brake lights or fuel pump (not sure about where they put those in a cummins, but if its close enough to the welding, and because it is a fuel pump, it would somehow be wired in to a TPS...see where I'm going with this?) when there is not 1/4" worth of bed in the way. I am in no way any sort of physicist, but I would guess this may be the reason welding rigs don't have a problem-the bed, due to its sheer thickness, adsorbs the pulse energy and dissipates it through the truck rather than passing right through, whereas thin sheet metal allows alot of the radiated energy to pass right through until it hits something of greater density-such as lead, or COPPER, which is, what a coincidence, a great electrical conducter.
A solution for such a case would be to make the table a sort of "booth", with vertical sides of substantial thickness to isolate the truck from any direct EM radiation. But if you are not entered in the tuff man competition and therefore cannot pick up 300 lbs worth of awkwardly shaped steel, then perhaps the only other way I can think of to avoid your electrical circuits absorbing EM radiation would be to isolate the radiation itself through earlier mentioned method of building legs onto the table and just move it away from your truck.
HTH!
G. L.
Interesting theory and it makes sense. My bed is made almost entirely of 1/4" diamond plate. There are 6 large tool boxes made of 10ga, and the truck is double framed. The poor thing weighs alsmost 14,000lbs! I don't know if there's enough mass to absorb the energy we're talking about tho.
My work table is 2' X 3' and is attached to a 2" square tube that slides into the trailer receiver. It's ALREADY "300 lbs worth of awkwardly shaped steel"! I'm thinking of making some kind of 'drawer' arrangement that would have an interior of 1/2" thick plastic. The table could slide into that and it *SHOULD* be insulated.
Thanks for the reply!
chaikwa.
