Hi, just found this site, and have been working on my truck. It is a 1976 f-250 with a 390. Before I started working on the engine. Truck was running fine. I replaced the valve cover gaskets, manifold gaskets, new plugs and wires and distributor cap. Now that everything is back together I get no spark. Truck turns over like a champ. But no spark. So i checked the ignition coil. Has power, but when i start it, no spark. So i tried to run straight from the battery to the coil just to get a spark. Nothing. except for spikey hair. I have also tried running power from different sources. Nothing. I have checked the grounds from the coil. I have checked all the grounds. They all seem fine. I now have my dashboard torn apart thinking it might be a ground problem somewhere or the wiring harness might have a problem with it. Everything seems fine so far. Any help would rock my socks.

Thanx

 

so a little more input would help alot. Did you pull the engine? did you disconnect engine harness? Disconnect wires from solenoid? does the motor turn over? does the solenoid click when key is on or just on start?

 

Is your ignition module good? That's where I would look.

 

so a little more input would help alot. Did you pull the engine? did you disconnect engine harness? Disconnect wires from solenoid? does the motor turn over? does the solenoid click when key is on or just on start

Did not pull the engine, left the engine harness in place. Motor turns over all day. only wires i touched were the wires to the ignition coil, the 4 way male connector to the 4way female connector to the 3 way connector to the distributor. (if that makes sense) I also replaced the starter relay. The starter itself was replaced about 2 years ago.

 

so if the ignition module goes bad, would i still have power to everything? IE coil, distributor and such?

 

the module is a great start. look at where the wires go into it and there is a colored bar that they go through. the best box that is an original unit would have a blue bar. the others tend to warm up when driving then cause the truck to die. then once cooled will work again but this will only cycle for so long before it just doesnt work. also make sure it is screwed down good and tight with a cleaner contact. less heat when grounded. my 2 cents

 

Connect a test light to the TACH side of coil and an engine ground. The light should blink with the engine cranking over. If the light stays ON and does not BLINK, then you could have a bad module, bad pickup module in the distributor, or no power to module.

And here's a dumb question, but it comes from a dumb guy who's been there: did you remove the rotor button and not put it back?

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No such thing as a dumb question. And what u said could be something i might of done once before. But everything is were it belongs. The more i read about stuff and talk to people the more its looking like its the ignition module. But here is a question...What makes the ignition module go bad all of a sudden when it was running 2 to 3 weeks before? Does this happen often?

 

it does happen out of nowhere out of the trucks iv owned its happened to about 2 of them but the did not have a module that was a blue plug on the box side. like i said they can just get warm and quit then work fine when cool but i did have one up and quit right away. did you hook the two wires on the solenoid wrong ( the ones that just push on the front)

 

My story sounds the same, rough idle if i could keep it running 77 f250 400 2bl a/c so i cleaned carb replaced filters no change. next day check cap and rotor, look new so i replace wires and plugs today no spark , test light on coil bat steady light other blinks when engine is cranked yet no spark at all today what else can i check and where is the best place to buy module?

Thanks to all with time and for letting me share this thread, they are so close

 

I went through this a couple weeks ago with my daughters 76 F250 High Boy. I tore the truck apart to put a new heater core and blower motor in and when I got all finished the truck wouldn't start. I replaced the cap, rotor, and coil and when that didn't work I took the module into NAPA where they tested it. They said it was toast. Put a new module in and the truck runs better than it ever has! Smooth idle and fires right up. Wish I had replaced the module a year ago when I was chasing a sporadic misfire that I couldn't track down...

 

Thanks, napa in the morn for me

 

Take a plug wire, if coil wire isn't long enough and connect to coil, place other end close to ground, crank engine to see if getting spark out of the coil.

 

Well, finally had a chance to get the new module. Have spark now. Now i have a different problem. The truck is trying to fire. I can hear the fuel igniting, i can see exhaust from the tail pipes. But it wont officialy start. It just keeps trying and trying. So maybe i flooded the engine? or timing? or something else?

 

Are you running a high-performance coil? If you don't run a ballast resistor inline with a high-output coil the Duraspark module will toast eventually. I've even seen the epoxy potting in the back of the box get so hot it drips out onto the inner fender.