MSD vs Welding

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Bruce69Camaro
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MSD vs Welding

#1 Post by Bruce69Camaro » Mon Sep 20, 2010 5:31 am

I thought I heard that when you do any welding on your car, to disconnect the ground from the MSD box of you could fry it.

Is this a true statement?

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Re: MSD vs Welding

#2 Post by John_Heard » Mon Sep 20, 2010 10:28 am

I pull the plugs (+ & -) on mine when welding on the car.

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Re: MSD vs Welding

#3 Post by Bruce69Camaro » Mon Sep 20, 2010 10:50 am

The reason I'm asking is, my co-worker normally runs 8.8/8.9 and he just got done doing some suspension work which included welding.

He loaded it up, took it to the track and found out the hard way that the 7AL wasn't working. The car wouldn't idle, tach was going crazy and was popping.

I thought somewhere I read you had to pull the ground off the MSD box when welding was done.

thanks

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Re: MSD vs Welding

#4 Post by 79 Camaro » Mon Sep 20, 2010 6:35 pm

I am like John!! I disconnect EVERYTHING that goes to the box. Rather take the time to do that then spend another 700 bucks on another digital 7


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Re: MSD vs Welding

#5 Post by chpcamaro » Mon Sep 20, 2010 8:30 pm

mig welding should be ok but tig i would unplug everything
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Re: MSD vs Welding

#6 Post by Bruce69Camaro » Tue Sep 21, 2010 5:22 am

Thanks,

When you talk about disconnecting everything to the box, isn't that just the ground, power wires and the harness going to the distributor?

John/ 79 Camaro, when you mentioned plugs, are you referring to spark plugs or wire plugs?

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Bruce
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Re: MSD vs Welding

#7 Post by John_Heard » Tue Sep 21, 2010 8:45 am

Power plugs - on the Digital 7 box they have connectors on them that makes it quick and easy to unhook it.

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Re: MSD vs Welding

#8 Post by CDR Performance » Thu Sep 23, 2010 7:14 am

If it is a Digital box we remove it from the car.
If your tig'n take the box out. And don't put the box on top of the welder.... :smt021
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Re: MSD vs Welding

#9 Post by supernova » Thu Sep 23, 2010 11:40 am

Everything on my car is on a floating wiring system. Even the grounds are floated back to the battery. I just unhook the ground strap at the battery and that is it. Have had no problems wih welding on the car without removing the box.
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Re: MSD vs Welding

#10 Post by Bruce69Camaro » Tue Oct 12, 2010 5:56 am

Here's an update, my co-worker got his 7AL back from MSD and nothing was wrong with it, so his next thing was to check all the wiring and make sure everything was good and had tight connections. That all checked out, he ohm'd everything, even the rpm chips and plug wires, but he still has a slight miss with new plugs.

He ran out of time and didn't get to check the coil yet, but is there a way to tell if the coil is bad or weak by using a voltmeter?

Other then the coil, the distrubutor is the only thing left.

I'm going out here on a limb but if the toggle switch for his ignition was going bad, could that do it or is a toggle switch either good or bad and not weak?

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Re: MSD vs Welding

#11 Post by John_Heard » Tue Oct 12, 2010 6:25 am

Toggle switch "could" be a problem, but it's unlikely. You could measure the voltage where it supplies the ignition at - wiggle the switch around some to make sure it's not intermittent or has excessive voltage drop across it. You got a coil you can borrow from someone to test?

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Re: MSD vs Welding

#12 Post by Bruce69Camaro » Tue Oct 12, 2010 6:53 am

John,

Yes he has a coil to try and I told him what your thoughts were yesterday when we talked about things.

I'm just trying to help him and rule out everything as we go and like I said, it's down to the coil and distributor.

The car ran fine before this all happened and only after the welding and suspension mods were made, then the miss appeared.

Tracks are closing soon and he wanted to get it down at least one more time and now this.

Thanks,

Bruce
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Re: MSD vs Welding

#13 Post by bonzibill » Fri Mar 02, 2012 3:19 pm

John_Heard wrote:I pull the plugs (+ & -) on mine when welding on the car.
Thats the best AND only way......

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