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-   -   ECM Unplug for Welding???? (http://www.wranglerforum.com/f210/ecm-unplug-for-welding-65761.html)

Dewry636 10-18-2010 08:25 PM

ECM Unplug for Welding????
 
I am planning to do some welding on the frame of my jeep to fix some rust problems.... Just curious if I could simply unplug the connectors from my computer (ECM) to avoid any possible current getting to it while welding the frame? Good Idea? Also, can I simply just plug it back in once finished with no problems? Would I have to re-program it or anything if I unplug it?

Thanks!

Jerry Bransford 10-18-2010 08:35 PM

There is no need to disconnect the PCM/ECM or battery while welding. Just connect your ground lead next to where you're welding and you won't have any problems with the welding damaging the ecm or anything else. Really. :)

Dewry636 10-18-2010 09:17 PM

Ok... Thanks for your quick response!

jeepjones 10-18-2010 09:27 PM

I'd unplug it if I were you. Unless you have a serge protector that goes in between your battery and ECM. It's cheap assurance that you won't fry it up.

bobsalmon 10-18-2010 09:54 PM

I am a mechanic and a bodyman at my shop. No need to disconnect. Just make sure your ground is close to where you are welding like the other comment said above me. The only current is going between those 2 points. If you connect all the way at the other end of the vehicle and your anode is at the opposite end...... well, perhaps there could be a problem. If you do remove the PCM, there isn't any need for programming. It's no diff. than having just replaced your battery.

rrich 10-18-2010 11:17 PM

Feeling lucky? Don't disconnect it.

If you win it costs nothing and you save 2 minutes - lose and it costs quite a bit, time and $$$.

I always disconnect - never had to buy a customer a computer.

Jerry Bransford 10-19-2010 12:50 AM

Electrically speaking, from one who has far more education in 'lectronics and 'lectricity than the average bear, there is no benefit to disconnecting the battery or ECM/PCM while welding so long as the welder's ground lead is attached near the work as is taught in basic Welding 101. It's strictly an old wive's tale that you need to disconnect the ECM/PCM or battery to prevent damage to anything in the Jeep. There's no "feeling lucky" about it, current flows between the electrode and ground and that's it. And let's face it, welders who might swear you have to disconnect the computer or battery are not exactly electrical or electronic engineers. They probably heard it from some other old welder who didn't know any better either.

rrich 10-19-2010 06:13 AM

True - the current flows between the electrodes.
But - if that was the only thing involved it would be simple. Radios would never work unless they were directly in the current path.

Something called RFI Radio Frequency Interference is at play here too.
Basic 101 - whenever a spark is generated all kinds of RFI is generated. RFI can contain high frequency spikes and high voltage components. It can be damaging to electronics devices. When you study electronics that's one of the first things you learn.

You can hear that interference on an AM radio as "spikes" or noise. - Ever heard lightening buzzing on your radio?

Why can lightening damage your computer or other things when the lightening strike is not directly to your computer? Striking the earth miles away obviously is not directly in the current path.

Why is it that when wearing a pacemaker doctors advise against welding and getting too close to power generating equipment? Are they misinformed as to what could trigger them?

Why is it Ford had so much problem with their ignition systems starting in '75 - passing a radio station, using a car Mobile Phone (before cell phones) or even installing a Police 2-way Radio created so many problems?

Why do they ask you to turn off electronic devices on an airplane - are they lying when they say it can interfere with radar and communications? Is that a Bin Ladin plot?

Why do hospitals ask you to not use your cell phone inside - do you think that when they say it can interfere with their medical equipment that's a Bin Ladin plot too?

Welding with an on-board computer can affect it one of 2 ways.
Worst way - it can actually damage it - the sensitive electronics devices in it can get blown out.
And probably more common - just like in your home computer - a "Spike" can be loaded into memory like data. But when it comes time for the computer to read and use that data, that random "spike" can cause all kinds of strange troubles. That's why often "deep cleaning" (resetting/rebooting - leaving the battery disconnected for at least 8 hours) the PCM gets the computer back on track and working properly. That bad data is forgotten.

Yes - There are some people that are uninformed and keep their head in the sand and claim it's all a hoax. They usually say they "know somebody" that does it all the time.

But - bottom line - if you really think today is the day you'll get lucky and not damage the computer, why aren't you in Vegas winning a fortune?

It's a game of Russian Roulette - yes you win most of the time.

It's so simple and easy to play it safe - simply disconnect the (+) battery cable and lay the cable end on ground. It's not a total cure-all, but it helps ground the electrical system.

Melissas6570 10-19-2010 10:21 AM

Quote:

Originally Posted by rrich (Post 827841)
True - the current flows between the electrodes.
But - if that was the only thing involved it would be simple. Radios would never work unless they were directly in the current path.

Something called RFI Radio Frequency Interference is at play here too.
Basic 101 - whenever a spark is generated all kinds of RFI is generated. RFI can contain high frequency spikes and high voltage components. It can be damaging to electronics devices. When you study electronics that's one of the first things you learn.

You can hear that interference on an AM radio as "spikes" or noise. - Ever heard lightening buzzing on your radio?

Why can lightening damage your computer or other things when the lightening strike is not directly to your computer? Striking the earth miles away obviously is not directly in the current path.

Why is it that when wearing a pacemaker doctors advise against welding and getting too close to power generating equipment? Are they misinformed as to what could trigger them?

Why is it Ford had so much problem with their ignition systems starting in '75 - passing a radio station, using a car Mobile Phone (before cell phones) or even installing a Police 2-way Radio created so many problems?

Why do they ask you to turn off electronic devices on an airplane - are they lying when they say it can interfere with radar and communications? Is that a Bin Ladin plot?

Why do hospitals ask you to not use your cell phone inside - do you think that when they say it can interfere with their medical equipment that's a Bin Ladin plot too?

Welding with an on-board computer can affect it one of 2 ways.
Worst way - it can actually damage it - the sensitive electronics devices in it can get blown out.
And probably more common - just like in your home computer - a "Spike" can be loaded into memory like data. But when it comes time for the computer to read and use that data, that random "spike" can cause all kinds of strange troubles. That's why often "deep cleaning" (resetting/rebooting - leaving the battery disconnected for at least 8 hours) the PCM gets the computer back on track and working properly. That bad data is forgotten.

Yes - There are some people that are uninformed and keep their head in the sand and claim it's all a hoax. They usually say they "know somebody" that does it all the time.

But - bottom line - if you really think today is the day you'll get lucky and not damage the computer, why aren't you in Vegas winning a fortune?

It's a game of Russian Roulette - yes you win most of the time.

It's so simple and easy to play it safe - simply disconnect the (+) battery cable and lay the cable end on ground. It's not a total cure-all, but it helps ground the electrical system.

While this is in some ways true. You also need to figure in how much the wave or spike will degrade over distance. You should also look into how much protection is built into the computer to guard aginst this interference. I can assure you that the PCU/ECU has a lot of protection. The examples that you gave are correct in some ways. They all were problems at some point in time. But are they problem now? Not so much. They continue to hang on because they did cause a problem at some point in time, and have never been removed. If you go back and look at the Ford automotive standard, they still require a chattering relay test. Is it useful today. No, cars dont have points in them anymore. The computers in a car are subjected to many nasty spikes and drop outs sags etc. with no damage. The automotive components are subjected to 200 volts per meter. You will not live but your car will. Your home pc is subjected to 10 Volts per meter, plus many nasty spikes and etc. Thats why they work much better today. One other example is if you are old enough and can remember when your mom used the Vac on Saturday, it would mess up the TV. You do not see that today. Because of the standards in place to suppress the emissions from the motor in the vac. If you look at the computer in a car, the mounting location, and the case it is shielded to the point of being hardened. Most of the units do not have vent holes, but use the metal case for cooling. If it has an opening it is small. The connection points of the cables are shielded inside the box, and have protection in place to discharge to ground the the spike, or RF, which will protect the electronics inside. If your were going to weld on the mount of the computer or close by the computer it might be one thing. But if you weld on the frame etc away from the computer its not a big deal.

One other thing you should look at is the fact that if you disconnect the computer, RF will still be hitting it. You do not need a cable connected for RF to travel on. Hence Radiated Emission, Radiated Susceptibility MIL-STD-461.

Square_Eyes 10-19-2010 10:32 AM

I just did some welding on my frame for a rear shock mount that broke, didn't disconnect anything, jeep runs fine started right up after I finished welding and drove just fine, it doesn't hurt to disconnect the battery or the ECM but it doesn't need to be disconnected

rrich 10-19-2010 12:50 PM

All true - and modern technology has improved bullets too. Now when you play Russian Roulette the bullet goes so fast through your brain it doesn't hurt or do any damage.

Yes - RFI is still present if the computer is still in close proximity. But the wires connected to it act like antennas and increase the effects. Unplug it and you've disconnected the antennas. Leave it plugged in the entire electrical system is the antenna.
Grounding the positive cable minimizes that antenna effect.
Removing the PCM and putting it in a grounded RFI-proof screen room would be the best, but certainly not practical.

This thread is so timely it's downright scary! I posted my replay early this morning, then went back to bed. I woke up about 3 hours later when my dog jumped up on the bed, she never does that.
Thunder!
We had an electrical storm - lots of lightening. The lights flickered then went out before I had a chance to turn off the computers.
We have 2 computers in the living room. My wife uses one, I use the other mainly to play the stock market.
My wife had been on her computer when it happened, both computers had been turned on.
After the electricity came back on and the storm passed, we restarted the computers. Mine came up fine, hers would/will not start properly.

Was that another Bin Laden plot?

She just called - Yucca Valley is getting hit with a huge electrical storm right now.

Recent electronics (and bullets) may be "LESS WORSE" than years ago, but still have the same old problems.

But we need someone as an example - so please when you weld on your frame DO NOT DISCONNECT ANYTHING. We need someone to be able to tell the ill effects of it.

Ibuildembig 10-19-2010 01:11 PM

yep I agree no need.....and I am an IEE :)

burton160w 10-19-2010 01:16 PM

You're also talking AC when your discussing computers. But just to disprove some of your "Bin Laden plots"

Hospital Hospital Equipment Unaffected By Cell Phone Use, Study Finds
Airplane Airlines ban cell phones -- but why? - ZDNet
Pacemaker Powered by Google Docs

And yes, with a pacemaker it's not that you can't weld - it's that certain precautions must be taken because you're correct, EMI can disrupt pacemaker use. But it isn't explicitly forbidden.

Why do hospitals and airlines not allow you to talk on your cell phone? Because it's friggen annoying! How do doctors communicate? Via pagers using same frequencies. Why can you use your cell phone on private charter flights or jets?

Jerry Bransford 10-19-2010 01:25 PM

And just as an aside, I weld on my TJ all the time and the guys I enjoy hanging/wheeling with like mrblaine and others weld on their Jeeps all the time too... and none of us have swallowed the rumors that you need to disconnect the battery or ECM/PCM. We don't disconnect anything, we just do the Welding 101 basic of connecting the ground clip next to what we are welding. No problems with anything, ever, and that's no rumor. :)

Ibuildembig 10-19-2010 01:30 PM

Haha I forgot to mention a few months back I was welding on my truggy and had the ground one the left knuckle, but was getting ready to weld on the passenger side. My neighbor walks in, turns the welder off, and says "Hey your about to weld the gears together"...I turned around and said what? what gears? he said the ring and pinion...I laughed so hard I fell backwards off the milk crate.

rrich 10-19-2010 01:58 PM

Sure is easy to tell who has tested the bullets!

I have a pacemaker - almost 2 years now. The instructions that came with the pacemaker say "Don't." If I mention it to doctors they all say "Don't." My doctors are at Loma Linda Hospital - they are some of the best heart specialists in the world. But they obviously know less?

I "push the limits" too, I still weld with mine - I try to keep that side of me as far away as possible from the arc.
MIG welding doesn't seem to affect it near as much as a regular stick AC welder. I've felt the pacemaker do weird - probably double triggering - the heart stops pumping blood when it does. Even standing too close to someone else welding with a stick welder affects it. Symptoms - weak feeling, vision goes blurry, feeling of losing consciousness. It hasn't triggered the defibrillator - yet.

That proves you can get away with things some of the time.

(Side note - I have the same make and model pacemaker as Dick Chaney - that's why my lawyer friends won't go duck hunting with me anymore.)

You can find most anything to justify anything on the web - just look at the elections - lots of bull, almost 0 truth.


Go ahead - please - we need an example.

Just because someone else gets away with robbing a store -

jgorm 10-19-2010 01:59 PM

Quote:

Originally Posted by Ibuildembig (Post 828654)
Haha I forgot to mention a few months back I was welding on my truggy and had the ground one the left knuckle, but was getting ready to weld on the passenger side. My neighbor walks in, turns the welder off, and says "Hey your about to weld the gears together"...I turned around and said what? what gears? he said the ring and pinion...I laughed so hard I fell backwards off the milk crate.

Yup, make sure that the current path does not flow through any heim joints or other type of joints and you will be fine. I've welded on vehicles 100s of times without unhooking anything.

Ibuildembig 10-19-2010 02:02 PM

Yep been welding for 20 years never had any issue

Melissas6570 10-19-2010 02:45 PM

Quote:

Originally Posted by rrich (Post 828564)
All true - and modern technology has improved bullets too. Now when you play Russian Roulette the bullet goes so fast through your brain it doesn't hurt or do any damage.

Yes - RFI is still present if the computer is still in close proximity. But the wires connected to it act like antennas and increase the effects. Unplug it and you've disconnected the antennas. Leave it plugged in the entire electrical system is the antenna.
Grounding the positive cable minimizes that antenna effect.
Removing the PCM and putting it in a grounded RFI-proof screen room would be the best, but certainly not practical.

This thread is so timely it's downright scary! I posted my replay early this morning, then went back to bed. I woke up about 3 hours later when my dog jumped up on the bed, she never does that.
Thunder!
We had an electrical storm - lots of lightening. The lights flickered then went out before I had a chance to turn off the computers.
We have 2 computers in the living room. My wife uses one, I use the other mainly to play the stock market.
My wife had been on her computer when it happened, both computers had been turned on.
After the electricity came back on and the storm passed, we restarted the computers. Mine came up fine, hers would/will not start properly.
Was that another Bin Laden plot?

She just called - Yucca Valley is getting hit with a huge electrical storm right now.

Recent electronics (and bullets) may be "LESS WORSE" than years ago, but still have the same old problems.

But we need someone as an example - so please when you weld on your frame DO NOT DISCONNECT ANYTHING. We need someone to be able to tell the ill effects of it.

Is it a hardware problem or is it Bill Gates?

Ibuildembig 10-19-2010 02:48 PM

I say Steve Jobs :)

Melissas6570 10-19-2010 03:17 PM

Quote:

Originally Posted by rrich (Post 828699)
Sure is easy to tell who has tested the bullets!

I have a pacemaker - almost 2 years now. The instructions that came with the pacemaker say "Don't." If I mention it to doctors they all say "Don't." My doctors are at Loma Linda Hospital - they are some of the best heart specialists in the world. But they obviously know less?

I "push the limits" too, I still weld with mine - I try to keep that side of me as far away as possible from the arc.
MIG welding doesn't seem to affect it near as much as a regular stick AC welder. I've felt the pacemaker do weird - probably double triggering - the heart stops pumping blood when it does. Even standing too close to someone else welding with a stick welder affects it. Symptoms - weak feeling, vision goes blurry, feeling of losing consciousness. It hasn't triggered the defibrillator - yet.

That proves you can get away with things some of the time.

(Side note - I have the same make and model pacemaker as Dick Chaney - that's why my lawyer friends won't go duck hunting with me anymore.)

You can find most anything to justify anything on the web - just look at the elections - lots of bull, almost 0 truth.


Go ahead - please - we need an example.

Just because someone else gets away with robbing a store -

How much shielding do you think is on the pacemaker? Not much.
Go figure. Its not made to be in a nasty environment. Look where the PCM is located. It is in a very bad place. Take a speca and a antenna and look around with the Jeep running. Its nasty. I am very shocked that you have not had a issue around the motor while its running.

Yes I know. I am a NARTE certified electromagnetic interference engineer. I have worked for UL conducting Medical testing and electronic compleance testing, and the Gov. doing MIL-STD-461, DO-160, HEMP, and HIRF testing.

Jerry Bransford 10-19-2010 03:21 PM

Quote:

Originally Posted by Melissas6570 (Post 828832)
Yes I know. I am a NARTE certified electromagnetic interference engineer. I have worked for UL conducting Medical testing and electronic compleance testing, and the Gov. doing MIL-STD-461, DO-160, HEMP, and HIRF testing.

Based on all that mumbo-jumbo and alphabet soup what could you possibly know about RF or other forms of electrical interference. ;) :D :rofl:

rrich 10-19-2010 05:00 PM

THEN GO AHEAD AND DO IT!

Do you think anyone really cares that you do it? Who cares if YOU damage YOURS? Try the new bullets - nobody will care about it either. After the first few tries, let us know how it felt.

My main objection is when so called "experts" that "claim" to be EE'S or welders or "in the know" because they "know someone that --," advise people to do things that are detrimental, risky, or just downright unsafe.

Especially when the preventative step is so simple. Or maybe it's not so simple for some to disconnect and ground the battery cable. Less than 2 minutes is clearly a waste of time for them - or do they have to hire it done?


Comment about the pacemaker - it does not have wires running all over me to run headlights, brakelights, turnsignals, a heater, AC, instruments, stereos, or accessories to act as long antennas. The longest wires are 2 wires about 3" long connecting into the heart muscle - and those are dual conductors with a shield. But still it gets affected.

Ibuildembig 10-19-2010 05:50 PM

Settle down beavis :)

I for one can back up my education and 20+ years of professional electronics experience in the field day in and day out.

I can also back up that I have personally welded everything from a jeep to a volvo 18 wheeler, to a kubota tractor all having ECMs and never had a problem. I do not have a pacemaker, but that wasn't the question the original poster asked.

burton160w 10-19-2010 06:35 PM

Someones getting his feelings hurt. What everyone here is basically telling you is that you do not have to. In fact, I just called a diesel mechanic who just finished schooling at Penn State and said that he's actually been instructed to leave the battery connected to act at worst, as a buffer.

And putting quotations around words doesn't make it a quote. Not a single person here used the phrase "expert" or "in the know."

See The “Blog” of “Unnecessary” Quotation Marks

I think what people have provided are significant backgrounds either through certifications or experience that do make them experts on the topic and can answer in an expert fashion what the proper precautions are. What constitutes an expert to you?

Do you remove the engine when you wash under the hood because you run the risk of getting water in the spark plug well?

Not to mention, your credibility lends to the fact that despite worrying about your PCM, you still weld while your doctors are saying not to.

baja 10-19-2010 07:06 PM

Quote:

Originally Posted by Melissas6570 (Post 828832)
How much shielding do you think is on the pacemaker? Not much.
Go figure. Its not made to be in a nasty environment. Look where the PCM is located. It is in a very bad place. Take a speca and a antenna and look around with the Jeep running. Its nasty. I am very shocked that you have not had a issue around the motor while its running.

Yes I know. I am a NARTE certified electromagnetic interference engineer. I have worked for UL conducting Medical testing and electronic compleance testing, and the Gov. doing MIL-STD-461, DO-160, HEMP, and HIRF testing.

I also have worked with hemp testing.:D

Jerry Bransford 10-19-2010 07:07 PM

Quote:

Originally Posted by baja (Post 829204)
I also have worked with hemp.

She's not talking about the smoking type of hemp. :D

baja 10-19-2010 07:09 PM

Yes but maybe I was a specialist at one time!

Jerry Bransford 10-19-2010 07:11 PM

Quote:

Originally Posted by baja (Post 829207)
Yes but maybe I was a specialist at one time!

But you can't remember right? :rofl:

baja 10-19-2010 07:21 PM

Remember what?


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