72 satellite 400 ci won't start

[Maxxx]

Tried Beaverton, they said orange not available anymore anywhere. They're looking for used but I think I'm moving on to MSD

 

[Don Frelier]

MSD Street Fire, works great in my charger. $189 from Summit
Rev limiter, starts like a champ, runs like a beast a great upgrade.
https://www.summitracing.com/parts/...MI_qnqzMqS3QIVUl8NCh1ZLgtWEAQYAiABEgJCJfD_BwE

 

[Maxxx]

Installing MSD 6AL system, seems straight forward, I need the +12V wire that was on the + side of the coil as input into the MSD box. However, both the wires that were attached to the + and - terminals on the coil (coil now completely removed) show 0V at rest, +12V with key in start and drops to ~9.x while cranking the starter. I've spoke to shop people who seem to know more than I do and they agree it's unusual for both coil wires to show this when disconnected from the coil. I will assume it's because the orange box (which is still in the circuit) is shorted and causing this issue. I will disconnect the orange box and hopefully see this reading on only one wire and not the other.

 

[Maxxx]

Update: disconnected the orange box and only the (pink) wire that was previously connected to the + side of the coil reads voltage under start and crank, the (purple) wire from the - terminal shows nothing. Not sure if this tells me everything I need to know about the orange box, but it's coming out anyways.

 

[Maxxx]

Last update: fixed the problem, and relieved that the coil is fine. Attached is photo of the MSD setup in "test mode". Now that it's fixed I'll tidy up the wires into harnesses etc. and mount the MSD box somewhere. Obviously the orange box was pooched, which vindicates Don Frelier's opinion in this thread. "Replacing one thing at a time" also proved the coil was still viable (for the moment). Thanks everyone for their input!

 

[Locodave64]

BTW the ballast resistor measured a consistent 0.8~0.9ohms, not sure if that's desirable?

You should see 1.2 ohms resistance. 0.0 is no resistance. The reason a ballast resister is in-line with the power feed to the coil. 12V-> battery voltage in and drops down output to around 6-8 V.

That said. There are a few different coil designs. What you have is a 6-8v coil. No internal resister. If the ballast resister gets shorted. It dosen't get the 6-8v output to the coil. Gets full battery volts reaching 13.7. Heats up the coil and the coil craps out.

And a few different Mopar styles on doing ignition systems. Point-condensor. Condensor goes bad you burn up the points. Might have spark from the coil. But the points won't chose when they close. The cyl to fire when the dizzy spins the rotor. Inside the cap. See any cracks in the cap when you look inside or outside. Rotor look ok? No cracks. Crack in shaft where it gets pushed down on the center metal shaft would make the spark ground to the shaft.

That's why I like to take a wire off a spark plug and put a phillips screwdriver in the hole. Hold it next to the block and have someone spin it over.

Mopar also used a single electronic dizzy pickup-> dual pickup with a start run relay.

Looked at a wiring diagram here. -> http://www.mymopar.com/downloads/1972/72SatelliteA.JPG

Now a Q for you. Do you have a point system or electrical pick-up in the dizzy? Key on or in start. Is the coil getting really hot?

Why buy an expensive ign module? Stock, if that one is bad? Are you gonna run it up to 6-8000 rpms? Want to loose the ballast resister. Just get a 12V coil with no internal resister. Jumper the ballast resister wires together. Input and output. Might like this sight to read.

-> http://www.fourforty.com/techstuff/ignition.html

 

[Locodave64]

Dang, typing away. You have it fixed. But hope what I wrote might help others. Instead of deleting it.

 

[Maxxx]

Thanks Dave, much appreciated! All good info