No juice from MSD box

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wazoo64

wazoo64

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Got a fairly new 6A box. Car has been sitting for 6 months and tried to start with no spark. MSD box has 12v going in but nothing coming out to coil. Orange wire to coil has no juice. Is the MSD box bad? We did a large welding project on car with battery disconnected but left the box connected. I'm thinking maybe that is what fried it. Any troubleshooting tips would be helpful
 
I did some troubleshooting and was able to get spark from coil to distributor. So I believe the box and coil to be good. There is no spark at the plugs. Could be a bad module. It's an mallory dist and have had multiple modules fry in the past. I think I'm going to msd dist. They are supposed to be less temperamental
 
if you are getting spark to the dist. then try the cap, rotor and wires first.
 
Make sure u have 12v while cranking. If the key is in run and u have spark the box works.
 
moparsegura said:
if you are getting spark to the dist. then try the cap, rotor and wires first.
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I concur

wazoo64 said:
All new parts. On my 4th module. Mallory sucks. I'm getting an msd distributor.
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Don't matter how new they are, if you have spark to the dist. but nothing coming out it has to be a problem with either the dist. cap or rotor. To have spark at the coil is reason to believe the dist. is working properly because it's what fires the MSD box. If the module in the dist. is bad you won't have spark anywhere.
 
Has it ever run with the current distributor? If it's a Mallory Unilite, you need to index that distributor or it'll never fire. There's a thread around here somewhere on how to do it.
 
I'm wondering if you have created a "rotor phasing" problem.

Some electronics are designed to trigger on the leading edge of the trigger, some on the negative side. I have not checked into the Mallory/ MSD combo. Maybe the MSD is triggering LATE and firing after the rotor has passed the contacts.
 
StrokerScamp said:
Has it ever run with the current distributor? If it's a Mallory Unilite, you need to index that distributor or it'll never fire. There's a thread around here somewhere on how to do it.
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My Mallory Unilite indexed just like a factory dist. I think it's the MSD dist. that requires indexing.

67Dart273 said:
I'm wondering if you have created a "rotor phasing" problem.

Some electronics are designed to trigger on the leading edge of the trigger, some on the negative side. I have not checked into the Mallory/ MSD combo. Maybe the MSD is triggering LATE and firing after the rotor has passed the contacts.
Click to expand...

You can't mess up the rotor phasing on the Unilite because it's firing design is slots in the rotor curtain that passes by an optical eye so it always fires when the rotor is aligned properly. It's a very simple and nearly fool proof design. Only drawback to them is the fragile module that burns out easily.
 
Yeah, but he's got it hooked to an MSD box, I guess? I thought maybe that interface was screwing it up?
 
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