Details:
1979 Ford F-250 with a 6.6 or 400.
It wouldn't start a few days ago. It had been starting fine and no intermittent trouble. No lack of performance issues before this either. The battery is fully charged, the starter spins it just fine. I confirmed I have gas in the carb so I narrowed it down to ignition.

After looking at many threads, I found FMC400's advice and did the test light check. I hooked the clip to a good ground and the other end to the "tach" side of coil. I cranked and had no blinking of the light. I also confirmed the rotor was moving in the distributer by having my son crank it while I watched it.

I thought the next step was to go to the wires into the control module. I had 11.65 volts on the "run" prong (green wire) and 0.0 on the start (black wire). ( I could have that mixed around as it was a few hours ago). I don't think I had any voltage at the red or white connection (the two prong plug) I then checked the ohm resistance between the purple and orange wire coming out of the distributor. It was within spec I believe at 650 ohms. I think I read it should be between 400-700 ohms.

So I thought the control module was bad. I bought a new one and installed it. The truck started for about 15-20 seconds and ran poorly. Then died and wouldn't re-start.
A visual inspection of the cap/rotor looked good. They were replaced about a year ago and have maybe 2000 miles on them.

Before I got it started I removed a spark plug and it had gas on it. Do you think it is just flooded? It wasn't soaking wet but there was moisture. I would have thought in even 15 seconds of running it would have burned the gas off.

Any help is greatly appreciated.

 

A little gas on the plugs after the motor won't start is expected and shouldn't keep it from running. What does the test light say this time? In other words, what happens if you repeat this procedure with this second no-start condition?

 

I will try the test light tonight if I still have some light when I get home from my son's track meet.

I realize now after reading a few more threads that I should have wiggled the purple/orange wires on the magnetic pickup coil when I checked it.

thanks for the help.

 

Checked the tach side of coil while cranking and no light.

I believe I can confirm the coil is good because I performed these tests:
Check for primary resistance by checking the ohms from the battery side to the tach side of coil, I got 1 ohm give or take.
I checked the secondary resistance by taking off the coil wire and testing from the batt side of coil to the high voltage terminal. This was like 8500 ohms give or take. I believe it can range from 7,500 to 10,500 right?

 

By "no light," I assume you mean that not only did the light not BLINK, it did not even come ON solid? If so, and you're confident that the test light was connected securely (including its ground), then there are three possibilities:

1) Coil is not receiving power
2) Coil primary winding is open circuit (you've eliminated this possibility with your previous measurements, which look good)
3) Coil primary winding is shorted to ground, inside the module or elsewhere

Next, unplug the coil, turn the key to RUN, and measure the voltage at the positive terminal of the coil connector with respect to engine ground.

 

D4PZ-12A112-A .. Stator aka Magnetic Pickup Coil (Motorcraft DU-1A) / Available from Ford/auto parts stores.

Located inside dizzy, symptoms similar as failing DuraSpark ignition module.

Applications: ALL 1974/79 FoMoCo V8's with DuraSpark except 1979 LTD/Grand Marquis 351W with EEC.

 

I had my dumb @ss moment and wasn't checking the coil with the connector attached! So I did this morning and got a solid light, no blinking when cranking.

I then checked the voltage at the Batt side of coil connector with key in run. I got 11.7o. I've got the battery charger on because I think my attempts at starting have drained it some. I get 12.08 at both batt terminals with my meter.

 

Good deal. The solid ON means the module is not switching the coil, which could be for the following reasons:

1) No power to module.
2) Bad module.
3) Bad pickup.
4) No connection between pickup and module.

Start with #1, which it looks like you started at one point. Disconnect the module and focus on the two-terminal female connector coming from the TRUCK. The RED with BLUE stripe wire should have power with the key in START. The WHITE wire should have power with the key in RUN. Report your results. Note that these colors may be flipped when they're plugged into the module, but that's OK.

The female terminals are typically too deep to fit a meter probe inside, so you may have to "cheat" by putting a paperclip into the terminal, and probing the paperclip. Be careful not to damage the contacts inside. Also observe any apparent corrosion or damage to either the 2-terminal or 4-terminal connectors coming from the TRUCK.

 

I got 12 volts with the truck in run. And about 9.5 with it cranking in start.

 

Forgot to mention, no corrosion on the connections. Someone had used a lot of dialetic grease on that connection.

 

The 9.5 volts on the start position was with the starter turning. I forgot to include that and I know it makes a difference.

 

I'm guessing that's the WHITE wire coming from the TRUCK? What about the RED with BLUE stripe wire coming from the TRUCK?

After clarifying that, measure the voltage at the positive terminal of the coil (BATT) with the key in RUN (coil connected), and report your results.

What part of MO are you from? I grew up in MO and lived all over the state.

 

White wire was right at 12 volts. Red wire was like 9.5 and a minor shock.
I have no red/blue wire coming from truck. It is odd I have a 3 prong plug but only 2 wires going into it.

I'm in Lee's Summit, MO which is a KC suburb. Right now I wished you were here to "show me" what the heck I'm doing wrong.

 

Sorry just re-read what you wrote and maybe my red wire has a blue stripe. I didn't clean enough of the dust off of it to take notice. The red voltage was while cranking and the white was with key in run.

 

The voltage at the coil with it connected at the batt side was 6.75 with the key in the run position.