I had the same problem last week. It turned out to be the starter relay (near the battery tray on the harness).

 

No, just on the Positive side. And it shouldn't be 12 volts on factory coils. The voltage from going through the ignition ballast resistor should bring it down to 7 or 8 volts.

You should only get a Pulse on the negative side when the coil fires, or each and every time it fires. If you have voltage here, without the coil firing, the negative coil wire is shorted to ground somehow. This will keep the coil colapsed, and prevent it from firing.

 

I think you meant to say the negative coil wire is open somehow not shorted to ground.

What you said is true for the Duraspark II Ignition system but do you know if this is also true for the Duraspark III Ignition system as asked?

The Duraspark III system ICM is Computer Controlled somewhat like the EEC IV Ignition system.

The EEC IV Ignition system the coil has 12 Volts on both sides with the key on (in the run position) and the engine not running.

 

Either condition would cause the coil to fail to spark. If there is 12V at the Negative coil wire, it's connected to ground somehow. I meant to say this condition would keep the coil from colapsing, thus causing it not to fire. Open circut would keep the coil colapsed, thus causing it not to fire.

Yes, the difference between the duraspark-III and II modules is...

Orange wire comes from the EEC-III instead of the stator in the distributor to the module,

The Purple wire is deleted on the DS-III, but on DS-II it goes from the module to the stator.

And the Black wire goes to ground on both DSII and III, but on III it doesn't ground at the distributor.

Other than these, it's wired exactly like a DS-II system. The negative coil wire does not go to the EEC-III, it goes from the coil to the DS-III module, and tachometer (if equipped) only.

The EEC-III or CP sensor can cause a no spark condition and is very simular to the DS-II's stator in the distributor going out.

Correct, but the control is limited. The DS-III is virtually identical to the DS-II except, the CP-sensor and the EEC-III takes the place of the stator and vacuum and centrifugal advances. Otherwise except for those differences, the DS-III module is virtually identical to the DS-II.

Right, my service manual doesn't specify this clearly, so this is a good point. However, if he does have power at the negative terminal of the coil, it should pulse as he tries to start it. If it doesn't then it's shorted to ground somehow. won't let the coil colapse.

 

Subford can you email me, i have questions about the eec-111 system on a 83 ford f250. THanks Cameron-k@sbcglobal.net

 

@subford is another guy who can maybe help with this, I'll also try pinging him (asking people to help you privately in e-mail or PM is really frowned on in forums like this).

If he comes to this thread, we should tell him you have another thread here (well, you hijacked somebody else's thread from years ago but same difference):

https://www.ford-trucks.com/forums/1...h-a-thing.html