I have an '81 with a factory equipped 351w EEC-III engine. It is a California truck.

EEC-III distributors are easy to identify. The rotor has two electrodes and it fires alternately from both of them. The poles on the cap are also staggard in hight:



There is no reluctor or stator in the distributor because it uses a crankshaft position sensor or CPS. There is no vacuum or mechanical advance because the spark is controlled by the ECM and can provide up to 50° of advance.

Only one module is made for the EEC-III ignition. It has a brown grommet and five wires vs the DS-II ignition's six wires. BTW, the yellow grommet is for the high altitude DS-II variant.



One other important difference between a DS-II distributor and a DS-III distributor: The engine firing order is the same, but the order of the wires on the cap is totaly different. The reason the distributor cap is wired different from the actual firing order is because Dura Spark III distributor's fire alternately from both sides of the rotor. That's why the rotor has electrodes on both sides. (If you start from #1 and jump back and forth 180 degrees Counter Clock Wise you will see the normal firing order.)

351w firing order: CCW 1-3-7-2-6-5-4-8

351w wire order: CCW 1-5-7-8-6-3-4-2 (EEC-III/Dura Spark III distributors only.)

Now after viewing my photos, can you identify which ignition system you have? If you have an EEC-III engine, you are going to have to use the correct replacement parts to keep it working.

 

have not figured how to do the links
go to electrical forum
look on page three
thread label, ignition problems, dura spark for a 72 F100

 

HorsePuller: That is exactly the setup that was in the truck when I bought it. After the truck started dying once it heated up I had a member of FTE come look at it and he is trying to show me how to switch from that setup to the blue grommet/vacuum advance dizzy. Is this possible?

 

If you have a Duraspark II distributor (the one with the pickup coil) and an Ig. Module with the blue grommet then just wire them color for color as I posted earlier for Duraspark II. Can't be all that difficult if you do one wire at a time. If you can't find the proper connectors just cut the connectors off, strip the insulation from the wire ends and twist the wire ends together using small wire nuts from any hardware store.

 

Ok, yes I have the parts and I already printed out what you stated earlier. After HorsePuller posted and I saw my old setup and realized it really was a California truck a light went on and I had to be sure before I went forward with the conversion. Just one more thing. I see that the shaft from the original distributor is longer than my current 83' one. Should I replace the shaft with the old one? I mean the shaft that drives the oil pump.
-Thank you

-John

 

I have no idea about the shaft lengths. I had thought the Duraspark II distributor would be a drop in replacement for the EEC dist. Hopefully someone else can help you on that. Maybe you'd be better off posing that question in the Engine Forum that covers 351W's.

 

Ok, thanks

 

Yes, I believe the distributors are different length.

You will have a better conversion if you change carburators too. Because the ECM controls the Variable Venturi Carburator and it takes information from the Throttle Position Switch.

Everything now controlled by the ECM will have to be switched over to thermal/vacuum switches for best operation. Once you break the link in the chain of the ECM's operation by removing a componet it goes into a default mode with fixed outputs.

The solenoids for the air pump, EGR valve, evaporative emissions system, all that stuff and more.

 

One of the previous owners already put an Edelbrock manifold and an Edelbrock 600 (cfm?) carburetor so I think (not sure) that part is taken care of.

 

Okay, you are half way there then. See the edits I made to my last post.

 

Whoa! I think since I get the feeling from members that the conversion will work I'll do the first part. And then I'll get back to your edit... kinda scared me for a min. I'm not a very good wrencher yet but I'll get there. I'm gonna post back when I get the first part done so thank you very much for helping me everyone here!