Alright I have a 1985 F150 with with 351w. Fender mounted ignition module. I currently have no spark. I am getting fuel. Now let me explain everything o can down to finest details. Bought the truck and it ran alright no major issues besides some wiring issues in the gauge cluster and a really bad exhaust leak. One day on my way to O'Reillys to pick up plugs and wires it started losing power and died. Replaced my wires and plugs because 2 put of the 8 wires were barely even attached. Ran fine for a week or so. Than again I lost power and died. So I replaced the main coil next to the distributor. Again was running fine. Earlier last week I was in a hurry and was getting o. The throttle and noticed it was msfiring so let up but I would misfire realm badly at times and all together die but not completely die. Like it just stopped running at normal rpms and went to a very low idol. If I gave it gas it'd start to flood the cylinders and act like I was down shifting of I was driving a manual so pretty much bogging it down. Than every now and than itd die completely. It would than crank but not start. If I let it sit it'd start up again. So I replaced the distributor thinking it was a bad pickup coil. After alot of very frustrating timing issues I got it timed perfectly and running smoother than ever. Took it out on the highway today and made it 3 miles before it started misfiring and dying. So than went to replace the gender mounted ignition module or brain box for some of you. Problem is I found out I have a high altitude emissions ignition module. Which has three connectors. And nobody had one in stock so o figured what the heck why not try the normal fender mounted igniton module that ford used on every single vehicle for ever made it seems like. The third connector went to a cylinder on top of the old ignition module which didn't connect to anything. So plugged In the new ignition module and it started fine. Took it home shut it off charged the battery for a few hours went outside pulled the charger off and started it no problem. Took it out got on the gas drove it hard no misfires so I figured it was fine. Took it to the gas station shut it off filled the tank went to start it and the battery by the way I should add is a piece of crap so it barely could crank my engine. So got some one to jump me and kt would crank fine but wouldn't start. So started testing everything I could at the moment. I have no spark to the spark plugs. Distributor is turning. Checked to make sure connections are tight. No spark from coil. But power to the coil. When doi g repeated cranking I noticed a burning smell in the cab but not outside it. I don't know if that helps but its not normal. I checked fuses even though I only have fuses for the power windows locks stereo lights windshield wipers ect. They were all good. Took a test light to the coil. Lights up when cranking not when key is on. Is that normal? also does the fender mounted ignition module ground through the bolts or through a wire cause the fender is plastic. Sorry this is so long but I need specific answers asap. Its my only vehicle. Any help is greatly appreciated

 

The module grounds through the distributor. There is a black wire that leads from the module back to the dist and it bolts to the metal inside the dist.

You need to check for voltage on the negative of the coil. Put your meter(testlight is better) on the negative of the coil and when the engine is cranked, the voltage shouldl blink on and off when it's turning over.

If you have voltage on the red wire of the ignition box (power for the ignition module) and it's not blinking on the negative of the coil, sounds like a bad ignition module. Also check for corrosion on the harness plugs for the dist and the module.

 

No corrosion on any of the connectors. The coil doesnt blink with test light on either side. You turn key on and no light on the test light, if you crank the engine the light just turns on no flashing

 

Just replaced the coil again. Thought that that might be it but still no spark.

 

Try the module. It grounds and ungrounds the coil(blinking voltage on the negative) to make the coil spark.