If your plasma is a blowback start (no high frequency) and you have the work ground clamp connected, then there will be no issues using a plasma cutter on a car. I have done so hundreds of times. Exhaust system removal....especially in rusty regions....is very efficient with plasma. No need to disconnect the battery.

Jim Colt Hypertherm

 

If your plasma is a blowback start (no high frequency)

How does one know if their plasma is blowback or high frequency start? I assume from your post that if it is high frequency start, then you risk damage to onboard electronics. Is there a way to mitigate that risk?

Is the HT Powermax30 XP blowback or high frequency start?

 

thanks for the reply!

getting an early start on it this morning so my headers can go in . just wanted to make sure it's ok.

 

Don't care about blowback, high frequency, or any other thing. DISCONNECT YOUR PCM!!!!!!!!!!!!!!!! It's cheap insurance, and only takes a few minutes. Stray voltage can really wreak havoc with computers.

 

The high voltage ignition system in todays gasoline engine autos is very similar to a the power levels of high frequency starting in older technology plasma torches. The ECU (0nboard computer) of these cars is very well protected from these high voltage pulses with isolation and filtering on its inputs. If ground straps that properly ground the ECU to the chassis of the car are not connected or are not making a good connection, then current flow from a welder, plasma cutter, etc could find its way back to the ECU and cause damage regardless of whether it is high frequency start or not. In some cases disconnecting a battery in a car...the welding/cutting can created current paths that are not good.

So, I will say again.....if you have a blowback start plasma with no high voltage/ high frequency starting circuit.....you can plasma cut on modern vehicles with no issues that will affect the computer as long as the work ground cable is connected to a good clean piece of metal on the chassis. A good work ground connection is the best current path....and will avoid current flow through the ECU.

With high frequency....this level of voltage can couple through other wiring and enter the ECU through unprotected inputs......and has a high probability of causing damage.

I personally do not recommend disconnecting the battery or any wiring....as you likely will make the issue worse by doing so. I have used blowback start plasma cutters on dozens of vehicles with no issues whatsoever. I would not use a high frequency start plasma or a high frequency tig without taking precautions as outlined by the vehicle manufacturer.

Jim Colt Hypertherm

 

FarmerSamm,

I am not here to argue with you or anyone. Just telling it like it is. If I thought a Plasmacutter (with ground clamp connected to clean metal) would hurt an auto engine control module (ECM) I would be the first to say so. The welding or cutting current....as long as it is not a high frequency start....will follow its path of least resistance to the work ground cable. There are many shops that replace exhaust systems daily on cars using plasma to remove the old parts. I have been a gearhead all my life....have used plasma on many of them for over 30 years.

Maybe the best advice is to not use a plasma on cars. I will continue to do so as will many others!

Jim Colt

 

Well gee Jim, I guess the folks at Ford are all morons

https://www.fleet.ford.com/truckbbas/non-html/Q123R2.pdf

 

https://www.fleet.ford.com/truckbbas/non-html/Q123R2.pdf

Just another reason not to buy Ford.

Begs the question is that just a blanket way of disallowing any and all electronic component failures? "You or someone must have welded on the vehicle. Warranty coverage denied.". :dizzy:

 

Be careful Jim..........I HAVE MY HAND POISED ON THE "MORON" BUTTON:laugh::jester:

They tell me I have to be nice these days

 

i don't consider them morons. I'll be happy to send the pictures of the gooseneck hitch in my F-250.'guess I dodged a bullet by plasma cutting and mig welding on the truck. Maybe a pic of the Toyota engine run in stand with the ECM inches away from welds and plasma cuts.
As I said in a previous comment follow manufacturers specs if you are nervous about it, and don't use high frequency start.
Jim

 

That was some interesting reading about FORDS and plasma cutting. Instead of using a plasma cutter on FORDS, I would just through them in the crusher.

 

If Ford recommends to do some crap, it doesn't mean that Jim is wrong. The angle grinder mfg's don't recommend to remove the guard people remove the guards all the time as people use their plasma cutters on their cars.:waving:

 

Back at the time of that service bulletin.....most Plasma cutters in the field were still high frequency start.....as Hypertherm's patent had not expired. Regardless......if you are concerned about plasma cutting or welding on a vehicle....don't do it. The rest of us will. There is no real difference between welding and plasma cutting (as long as it is not a high frequency start tig or plasma) on a vehicle.....and there are a few thousand of us that have been doing so for a long time with no issues.

What I expect happens is that the work ground clamp is connected to a rusty or isolated piece of the car....and the current path finds it's path of least resistance through something (a sensor) that is directly wired to the ECM (could be the oxygen sensor of you are welding or cutting on the exhaust). That could clearly cause a stray current path that would damage the ECM...or almost anything electrical.

Clean a connection on the part your are welding or cutting on.....make sure it is electrically conductive to where you will weld or cut....and there will be no issue. I have always assumed that everyone followed that same principal.....but maybe not!

High frequency on the other hand... directly (inductively) can couple through the insulation and wiring and will find its way to earth ground through any source possible....that is why it is not recommended to use this type of technology (HF start plasma or Tig) on a modern vehicle without removing or isolating the Engine computer.

Trust me....I am not saying this to sell more plasma systems (Farmersamm).....I am saying this to let people productively weld and cut on modern vehicles without the extra work of finding and disconnecting / removing ECM's.

Jim Colt

 

What I expect happens is that the work ground clamp is connected to a rusty or isolated piece of the car....and the current path finds it's path of least resistance through something (a sensor) that is directly wired to the ECM (could be the oxygen sensor of you are welding or cutting on the exhaust).

Hi Jim, Minor point of correction. Current takes ALL paths. Most of it takes the path of least resistance.

 

Look,
Sam would rather use 6011 for cutting then any plasma. Just trying to get him to use dual-shield would take a act of congress. Even then, being a Indian from Oklahoma, doubt that that would do it either..:laugh:

 

I think you all have missed the most important safety concern. Don't use the plasma cutter on the gas tank. Geez guys! :jester:

 

Won't work. My gas tank is plastic.

 

Back to the basics, I'm sure you are not the first mechanic to remove an EGR valve on that model vehicle. You can still cut the manifold if you want, using the precautions mentioned, at least disconnect the battery and keep your ground close and from going through any moving parts. However, I would think the professional way to do it is find out how the dealers do it. the tool truck may have a special socket for it. You might get lucky by googling it, it might be on utube or something.

 

I mig weld on vehicles either panel replacement or exhaust work on a weekly if not daily basis. Always keep the ground close to where I'm welding. I don't ever disconnect the pcm or disconnect the battery. I guess I have been lucky. I don't think plasma would be a problem if using the above mentioned precautions. I have used a die grinder cutoff tool for stuff like that. I don't have a plasma but I have a huge powerful dewalt sawsall, it goes through the blades but it gets it done. A plasma is on my wishlist though.

 

My pilot arc will still go right through it, but nice try.

 

The crank sensor broke off in the bell housing on my truck this week. I tried to drill it out and put a screw in it to pull it out and the screw broke. So I blew through it with my plasma cutter. She's running now!
Where would I be without these wonderful tools lol

 

Its a lot safer then with a O/A torch

 

As an observation, I've noticed plasma doesn't respect boundaries between metals as well as O/A does. If you're watching what you're doing you can split a nut off a bolt without any or much harm to the bolt. Plasma tends to cut every thing in the path of the stream. Cutting a nut off a bolt you will likely cut the heck out of the bolt and maybe even whatever is bolted up.

Everything has a place.

 

+1

I've used O/A to burn out a broken tap using the pure oxygen stream without damaging the metal it was in at all. Can't do that with plasma, but then again, there are times where that indiscriminate behavior is an advantage too.

 

I cut every bolt off holding the plow mount to our last truck. I only cut into the mount/frame twice out of all the bolts with the plasma cutter.

 

the best answer is, disconnect battery. ecm if you want to go to trouble but not ever done myself. 35 years body work in dealers, and yes, have smoked 2 dodge radios and one ecm. forgot to disconnect batteries.

 

I don't give a damn if your're changing the wiper blades or working on a window.. Disconnect the battery and clean the stuff up/reconnect when you're done.
Don't be a slacker. Check the oil, brake fluid, power steering and belts while your uglyazz is in there. That's courteous to the victim and might be appreciated. I even check the air in the tires real quick.

 

. I even check the air in the tires real quick.

I usually wax the car also.
And armor all the tires




Sent from my iPhone using Tapatalk Pro

 

Disconnecting the battery is an old wives tale. If you fried something in the car you had the ground in the wrong spot.

 

But it doesn't hurt a thing and disconnect +& - any equation you can take away the better

 

I always move, plastic bags, magazines, gas cans, to the front seat
when using my plasma cutter..

Charl

 

Bare metal is the best place to attach your ground.

 

I will sometimes disconnect the battery because I'm afraid of air bags. Replacement cost more than most of my vehicles.

 

I have cut and welded on thousands of cars. Thousands of modern trucks are used every day as welding work platforms.