1972 duster 340 fires up then dies and will not stay running

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Cardinge72

72duster340
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When I go to start my stock 340 it fires up then dies instantly. So far I’ve changed dist. Cap,rotor, pick up coil,plug wires,electronic box,voltage regulator. If I ride the starter car will start sometimes and then it begins to miss fire on the passenger side. Not sure what to look for here. Car is also getting lots of fuel. Could this be a ignition issue not sure what to look for here
 
To prove it, just run a jumper from 12volt source over to the Coil plus. Battery or alternator work for me.
"and then it begins to miss fire on the passenger side." separate problem. Replace the ballast first.
 
May not be related but is the 12 volt from the ignition stay hot? There is two sources of 12 volts. one from the start, when key is turned to that position. The other is the run which is the constant 12 volts.
I had a problem that it would fire but then die it was the 12 volts from the run circuit not staying on. Just my problem that I am passing on.
 
I had an issue with a simple PCV sticking closed on a 71 340 Demon that caused it to sputter and die! I had no idea that something that small would have a huge affect...but then again I was 15 years old!

Only three things that make an engine go... gas, fire and air!
 
Steven190 said:
May not be related but is the 12 volt from the ignition stay hot? There is two sources of 12 volts. one from the start, when key is turned to that position. The other is the run which is the constant 12 volts.
I had a problem that it would fire but then die it was the 12 volts from the run circuit not staying on. Just my problem that I am passing on.
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I had that problem too in the past. Coil had power when cranking, but not in run position, so car would start while you were cranking the starter, but as soon as you let go of the key it would die.
 
sounds like classic ballast resistor problem to me.....this should be a sticky somewhere on this site!
 
bbrroowwnn said:
.....this should be a sticky somewhere on this site!
Click to expand...

Why, you getting tired of saying it after a few hundred times? :D
It could actually be the ignition switch or ballast resistor either one, but the resistor is the best bet first since it's cheap and so much easier to swap out.

One day I was on my way somewhere and saw a Duster on the side of the road with the hood up and a guy kinda standing there looking at it so I stopped.
He had exactly those same symptoms.
When I swapped to HEI I tossed the OE ignition box and ballast in the accessories box in the trunk.
The guy was pretty surprised when I had the part with me for a 40 year old car and he was able to drive away.
 
TrailBeast said:
Why, you getting tired of saying it after a few hundred times? :D
It could actually be the ignition switch or ballast resistor either one, but the resistor is the best bet first since it's cheap and so much easier to swap out.

One day I was on my way somewhere and saw a Duster on the side of the road with the hood up and a guy kinda standing there looking at it so I stopped.
He had exactly those same symptoms.
When I swapped to HEI I tossed the OE ignition box and ballast in the accessories box in the trunk.
The guy was pretty surprised when I had the part with me for a 40 year old car and he was able to drive away.
Click to expand...
Just bypass the damn thing with a jumper and alligator clips. see how it runs. Eliminate the ballast from the problem list.....
 
CowBoyRoy81 said:
Maybe too much fuel?
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Could be. Holley needle and seat going bad would put direct fuel pump psi straight through the boosters and flood it out, wetting plugs and mis firing till shut down. Only if that is remedied would reving it up...clean it up to stay running.
 
Mopar Tim said:
Just bypass the damn thing with a jumper and alligator clips. see how it runs. Eliminate the ballast from the problem list.....
Click to expand...
It wouldn't run if it was the ballast, that's the power to the coil.
It just doesn't start at all.
But hey maybe a short, just turn the key in the run position and test for power at coil.
No power, jump it with a wire...and if it works, then change the ballast, otherwise check your ignition switch or wiring to it.
 
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I just had that problem at Carlisle this year. The connection in the bulkhead was no good. The bulkhead was slightly deformed from heat. Just follow the wire from the ballast resistor to the bulkhead and check that connection.
 
MOPAROFFICIAL said:
It wouldn't run if it was the ballast, that's the power to the coil.
It just doesn't start at all.
But hey maybe a short, just turn the key in the run position and test for power at coil.
No power, jump it with a wire...and if it works, then change the ballast, otherwise check your ignition switch or wiring to it.
Click to expand...
Hmmmm ok
 
Its not running, right, So "It wouldn't run if it was the ballast"?
 
MOPAROFFICIAL said:
When my ballast goes out, it doesn't fire period.
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I had the same problem. I bypassed the Ballast resistor and it started and stayed running om my 1970 duster 340. It will start with a bad Ballast depending if it is not totally shot (meaning the resistance is open). The resistor probably is causing to much voltage drop. Just bypass it.
 
True, the OP stated it seemed to try running "riding the starter", the usually brown wire bypasses the ballast during cranking. Hence, Uhh yeah she'll fire cranking & die when
You let off with a bad ballast..............................

EDIT; By no means is that the only possible cause, poor connections to the ballast
from the ign. sw. incl the sw. & splices can mean low/no voltage ....normally dk blue wire.........
 
OP asks for advice, I give him some, "it is not that" LOL only takes 1 minute to bypass the ballast and find out for sure if it is the trouble or not. "No It's not that"...Wont hurt anything to bypass for test.
70188678.jpg
 
Mopar Tim said:
OP asks for advice, I give him some, "it is not that" LOL only takes 1 minute to bypass the ballast and find out for sure if it is the trouble or not. "No It's not that"...Wont hurt anything to bypass for test. View attachment 1715133391
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Don't let it keep you up at night.
Op hasn't come back with anything.
Hope it's as simple as the ballast,for his sake and for the sake of your sleeping at night. Jk
 
MOPAROFFICIAL said:
Don't let it keep you up at night.
Op hasn't come back with anything.
Hope it's as simple as the ballast,for his sake and for the sake of your sleeping at night. Jk
Click to expand...
LOL. Yep. :lol: Probably the bulkhead connector.:lol:
 
Sometimes ballast resistors test good ohms cold, then crap out as they get hot. Just sayin'...
 
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