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68 GTX need diagnosis help

Darth Ooten

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Feb 22, 2022
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Redding ca
For background the car has a 440 msd 6al, msd distributor, and mopar orange box. I was out running errands. Heading home the car started stumbling, the aftermarket tach went to zero (car still running). I got to the side of the road and it backfired once and quit with a little white smoke for the right side if the hood. There is a voltage regulator and the orange box in that area. I didn't build the car and have made no changed under the hood. I'm not good with electrical but feel like it's either the orange box or the regulator. Any other advice where to start diagnosing? Thanks
 
First thing I would look at is the bulkhead connector.
 
Not sure why you would need the orange box and the MSD6al. The aftermarket orange boxes are crap and are subject to die at any given moment. In the diagram below it shows the Orange box disconnected.

msd_6al_wiring-jpg.jpg
 
Bulkhead connector seems in good shape. No melting or burnt wires. I thought it was odd myself that the orange box was left in it but thought someone new better than me. It ran fine till this morning (had it about 4 months). At this point if I put the key in it the starter will click but it won't turn over.
 
Need to know which ignition system is being used. MSD directions show how you can switch systems like they're expecting failure.:BangHead:
 
Look really close at the wiring. The alternator loom on my 66 had melted but didn’t fry the wiring. Upon close look the main copper conductor was just laying in a neat pool of melted and resolidified insulation that looked just fine from above. However the bays on the bulkhead were pretty melted out. Otherwise, yeah MSD - May Die Suddenly, at any moment.
 
Well I got it home and changed the battery. Checked the obvious places those looked good. It cranked and fired, alternator is putting out good voltage. Could a simple bad battery cause the ignition to shut down?
 
For background the car has a 440 msd 6al, msd distributor, and mopar orange box. I was out running errands. Heading home the car started stumbling, the aftermarket tach went to zero (car still running). I got to the side of the road and it backfired once and quit with a little white smoke for the right side if the hood. There is a voltage regulator and the orange box in that area. I didn't build the car and have made no changed under the hood. I'm not good with electrical but feel like it's either the orange box or the regulator. Any other advice where to start diagnosing? Thanks

WHY would you have an MSD 6AL, MSD Distributor, and MOPAR ORANGE BOX, in the same system?? It sounds like everything is at war with each other.....
BOB RENTON
 
Well I got it home and changed the battery. Checked the obvious places those looked good. It cranked and fired, alternator is putting out good voltage. Could a simple bad battery cause the ignition to shut down?
MSD’s are very sensitive to constant voltage. Any slight drop in supplied voltage can make it stop switching. They can still power up with low voltage but not signal a pulse. It could have been the battery as your problem. I agree with the previous post on not needing the Orange box with the msd, it defeats the purpose of the msd. I would suggest using the msd with out the orange box but still leave it installed in case the MSD fails you have a backup. Just run a separate triggering wire to your distributor to the msd and leave the Orange box wire(s) to the distributor disconnect, so if the msd fails you just unplug it from the distributor and the plug back in the Orange box. Do a trail test with just the msd wired and then just the Orange box wired. I did that with my max wedge, I have separated wiring to the distributor points, one st runs to the coil like a standard point setup and a separate connector running to the distributor to run of the msd. I can switch from one to the other just by removing the white signal wire from the msd and replace it with the stock coil wired. But I run it on the MSD for the Multi spark feature. Good luck sorry I wrote a book!
 
I appreciate the help for sure. I'm here to learn from people who know more than me. I'll take a deep dive into it and separate everything out. Thank agains everyone for the input and suggestions.
 
that smoke came from somewhere, I'd keep looking for hot spots when running!
is the tach working again?
 
that smoke came from somewhere, I'd keep looking for hot spots when running!
is the tach working again?
The tach is working again. When I was trying to get it restarted it backfired through the carb and there was a small puff of smoke from the air cleaner. I'm going to continue to look but I'm hoping that was the culprit.
 
Not sure why you would need the orange box and the MSD6al. The aftermarket orange boxes are crap and are subject to die at any given moment. In the diagram below it shows the Orange box disconnected.

View attachment 1277090
Hey all, jumping in. I am now in the process of converting electronic ignition (Orange box, voltage regulator) and am moving to MSD for EFI box.
Is there a drawing somewhere regarding how to properly remove the old schematically?

Appreciate any help or Leads...
 
MSD has comprehensive instructions. You may wish to start your own thread/topic if it gets involved.
 
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