EEC-IV Frustrations


Really at my wit’s end…

86 EEC-iv F-150 Straight 6 carb.

Coil has power, but will not collapse and fire. Replaced ICM, Hall (PIP) sensor, Pigtail to connector, and have checked and rechecked wires in every direction. Could a bad ballast resistor or condensor (noise suppressor) be the culprit?


pull codes. with scanner, or old school analog meter.and watch the sweeps of the meter.


Classic failure of the ignition module. This is on the front of the distributor, and should be a gray module that the wire harness attaches to. Make sure you use the grease packet that comes with the replacement. It will fail again if that is not used. When you replaced the Hall sensor, did you use a feeler gauge to maintain the proper gap? This is very important to get right.


not spliting ATOMS, very known prob.



Yes, I started with the Ignition Control Module. It passed all its continuity tests, but I replaced it anyway thinking it was such a classic ICM problem- that it must be malfunctioning.

When that did not do it, I thought that the Hall might be the culprit. In that case the ignition module could be good, but just being fooled into thinking the engine was not turning.

Question about the Hall- How do you adjust the gap on it? It seemed to be bolted into a fixed position (at least the pick up and the vanes are in a fixed position, the generator is on a fixed pivot adjusted by the octane bar, but it is made for a range of firing conditions, so that does not seem vital.)

It seems that it has to be a wire, but I have ran straight jumpers to the four key ICM leads (minus the PIP going to the EEC and the Spout returning (which I believe is only used for advancing the spark and will fire in start mode whether the computer is there or not… and still nothing…

As far as the EEC codes… I live in Snowy Western NY with an 86 Ford Pickup- when I picked up the self test hook ups to run the tests, the connectors were connected to the fender with a green coppery glue- the powderey remains of what was wires. Only one wire remained attached, and all the other wires are literally nowhere to be found! Can any one tell me how to go to the EEC it self and run a code test?

Thanks again for the help…


What component did you change? Was it the ECM (Engine Control Module)? If so, that was the wrong, classic, component. The correct classic component for this problem is the TFI Module. It is attached to (usually) the side of the distributor with two screws (5/32, or Phillips, or common head screw).
You could cut off another wiring connector from a Ford in the salvage yard, and splice it into your truck.


Good news, I finally just went back to square one, or at least 1.5. I really concentrated on the primary ignition circuit, running my own wires and switches between everything- i now have a switch under my dash to turn on the ICM, and another to take it out of start mode and allow the EEC to advance the spark, but its running. I suspect I had two bad wires, and since I was only jumping one at a time, I failed to find both at once.
Moral of the story- be careful how quickly you rule out the unlikely.
I assumed it was a bad wire, and it turns out to be two bad wires instead.


Glad you got it successfully jury rigged. The wiring diagram can help you to identify, by color, each wire when you decide to repair the wiring. Click on this link, and click of Fig.20 >