1969 dart loses spark once it warms up

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Flatty30

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Hwy guys hope someone can help I have a 69 dart with a 360 it has MSD ignition (6al box) with a msd blaster coil and the distributor has been converted to electronic from points. It will start up fine when it has been sitting once it warns up it will lose its spark and stall and not start till it cools down again any ideas?
 
This is tough. Could be a number of things

1...Go to MSD site and READ the troubleshooting prodecture for the MSD

2...De-wire the MSD and "hot wire" the box, making CERTAIN that the big red and big black are well hooked to a good battery source and ground, and then "hot wire" the "small red."

3...Just try a spare coil. Coils can be intermittent, and back in the day, this would be a sign of a bad coil

4...Make DARN sure there is NOTHING connected to the coil, NOTH---ENG except the 2 wires from the MSD box

5...Any evidence of overheat/ moisture damage to the box/ coil?

Remember that MSD works nothing at all like a conventional "switched" or Kettering points / electronic ignition. These girls work more like a photoflash. They charge up a large capacitor to high voltage, and then the trigger dumps the charge across the coil.
 
WHAT DO YOU MEAN the distributor has been converted to electronic? Do you mean you have REPLACED the dist with a breakerless dist? What kind? Mopar? MSD? other?

Or has the points dist had some module like Pertronix added?

I would pull the dist connector and "work" it in/ out several times to 'scrub' the terminals and 'feel' for tightness. A magnetic breakerless dist has VERY little current (as in almost none) through that pickup circuit, so it takes LITTLE corrosion to fail

IF it is a dist that has adjustable reluctor gap (like Mopar) CHECK it with a brass feeler gauge, and check for rust/ debri/ other around the pickup/ releuctor, as well as shaft wear/ wobble/ loose/ etc

You can trigger an MSD off points (I think the white wire?) so if you still have your points dist, make sure the points are OK and set, and try it in place of
 
67Dart273 said:
WHAT DO YOU MEAN the distributor has been converted to electronic? Do you mean you have REPLACED the dist with a breakerless dist? What kind? Mopar? MSD? other?

Or has the points dist had some module like Pertronix added?

I would pull the dist connector and "work" it in/ out several times to 'scrub' the terminals and 'feel' for tightness. A magnetic breakerless dist has VERY little current (as in almost none) through that pickup circuit, so it takes LITTLE corrosion to fail

IF it is a dist that has adjustable reluctor gap (like Mopar) CHECK it with a brass feeler gauge, and check for rust/ debri/ other around the pickup/ releuctor, as well as shaft wear/ wobble/ loose/ etc

You can trigger an MSD off points (I think the white wire?) so if you still have your points dist, make sure the points are OK and set, and try it in place of
Click to expand...

I did not do the converse but it has a kit that removed the points from the old dist .I will have to check to see what was done to it when I remove the cap
 
OK, post that back. I would not think that is the "way to go" with MSD.
 
I had a Pinto that would do that. Never fixed it but the electronic control box was always my suspect!

but as others have said start with the easy stuff!
 
Flatty30 said:
Hwy guys hope someone can help I have a 69 dart with a 360 it has MSD ignition (6al box) with a msd blaster coil and the distributor has been converted to electronic from points. It will start up fine when it has been sitting once it warns up it will lose its spark and stall and not start till it cools down again any ideas?[/QUOT

So I was told at a MSD dealer to make sure my coil was mounted vertical .So I got a new coil mounted it and still the same. Started right away let it run for half an hour shut it off waited 15 min and would not start no spark from the plugs. I have spark from the coil . I think i will try changing the distributor tomorrow. That is all that is left .the MSd box and coil are new hope that solves the problem.
Click to expand...
 
What do you mean "I have spark from the coil?" Under what conditions?

If you have a good hot spark from the coil WHILE CRANKING WITH THE KEY then it should run, and MAYBE you have a fuel problem and not an ignition problem

Also mounting coils vertical "may be bullshit" because nowadays many coils are epoxy, not oil filled. Ford coils were mounted horizontally for years. So were B/RB Mopars
 
Does this look vertical to you?

img_0112-jpg.jpg
 
I had a 70's mopar with stock electronic ignition. When warmed up and running, all was ok. But, if I stopped to run into a store or other quick errand, the engine would not start when I returned until it had cooled down for a half hour or so. It would then start and run fine until the next time I shut off the engine again. I was able to diagnose that the reluctor coil was the culprit as it would "heat soak" and the coil would "open" until it would cool. A new reluctor took care of the issue for me.
 
William Tucker said:
I had a 70's mopar with stock electronic ignition. When warmed up and running, all was ok. But, if I stopped to run into a store or other quick errand, the engine would not start when I returned until it had cooled down for a half hour or so. It would then start and run fine until the next time I shut off the engine again. I was able to diagnose that the reluctor coil was the culprit as it would "heat soak" and the coil would "open" until it would cool. A new reluctor took care of the issue for me.
Click to expand...


this was my problem as well I changed it today and it has started every time. thanks for the info
 
The reluctor is the star wheel on the shaft. The pickup coil is the thing bolted inside with wires attached Pointing out the "permanent magnet" is redundant because it is not replaceable as a separate part.

NOTE: Can you tell what engine this dist. fits? Can you tell what it does NOT fit?

distributor.jpg
 
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Flatty30 said:
Hwy guys hope someone can help I have a 69 dart with a 360 it has MSD ignition (6al box) with a msd blaster coil and the distributor has been converted to electronic from points. It will start up fine when it has been sitting once it warns up it will lose its spark and stall and not start till it cools down again any ideas?
Click to expand...
Your Blaster coil is bad.. I had a similar problem and after doing this and that I tested my coil with a meter and the OHMs were way out. A new one eliminated my problem. Just to be sure, test your coil.
  • Primary resistance: .7 OHMs.
  • Secondary resistance: 4.5K OHMs.
 
check that the electronic module has heat sink compound/grease under it where it fixes to the points back plate. this helps heat transfer from the module to the base plate to stop it from overheating, which could be what you're experiencing. most 'conversions' come with a sachet of this grease and the instructions say to apply it under the module.
Heat Sink Compound, Pastes & Greases | Products for Electronics
neil.
 
You guys might read a thread before you jump. OP got the problem fixed. See post 15
 
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