First, this problem is on an old Lincoln but I think that this problem can happen with any DS system. 1980 Lincoln 351W engine. The problem is this. Keep replacing DS modules. If you drive it as little as 10 miles and then shut down it won't restart. As far as I know if you keep it running it is fine. That doesn't make a lot of sense, but anything is possible. Well, the module is then bad and fails testing. Put a new module in and it fires up and drive away. Have put several modules in it recently. Any ideas anyone? Has anyone experienced this with a truck or other Ford product. I think possibly coil or pick up inside of distributor. What else would cause the module to fail like that in a short period of time. I have thought also that a wire is being shorted to ground. Any direction would be appreciated.

 

Which Duraspark system do you have?

DS-II or DS-III? What color is the gromet on the Module?

And are you replacing the modules with Motorcraft "Ford" or aftermarket modules?

 

They are aftermarket from local box store. $18/each and they have I believe the blue plastic for the color

 

Ok, Duraspark-II.

I would test the harness first off. Remove it from the distributor, the coil, and the module and test the continuity of each color wire in turn, between the connectors, and between other wires. This will check for shorts, resistance, and breaks in the wires.

Then I would test the magnetic pickup in the distributor, and the coils primary and secondary resistance.

Replace or fix what's defective.

If all the above tests check out, I'd go and get a Ford Ignition module, they are not made in china. They are still avaliable new at Ford, but are 3X what you have been paying, but 3x the quality as well.

 

Here is a proceedure for checking the coil and the magnetic pickup in the distributor.

https://www.ford-trucks.com/forums/s...8&postcount=12

 

So, 81-F-Explorer, I assume from your diagnostic process that the problem possibly lies within the wires between the distributor to the module. Assuming short, broken wires. I will check out the link. That is my thinking also. I have not heard of these modules failing at this kind of rate. I am not sure if they are getting hot to the touch or not. I will find out more tomorrow. I will be sure to check out the wiring. What about the pick-up and other parts inside the distributor? Can they cause a failure also? Just wondering. Thanks for the replies. It is a big help.

 

If the DS2 boxes are getting hot and burning up then I would look for what is causing the heat.

High current means more heat. The current flow through the coil primary goes to the DS2 module next as it is a series circuit.

At idle the voltage at the coil positive connection should be LESS than battery voltage say 8-9 volts or so… higher voltage means high current flow through the coil primary. The DS2 needs a (or ballast resistor) resistor wire to lower the coil voltage which will also lower the current flow.

You should have a round coil meant to be used with the DS2 system with the correct primary resistance. If you have different coil with a lower resistance it will have higher current flow, thus more heat. Is the coil warm to the touch? Or hot?

 

The Pickup and the coil itself, etc... can also cause the module to fail.

The Diagnostic proceedure in the link should be able to tell you if the Coil or the pickup is malfunctioning or bad as well.