No fire after key replacement parts

[tmacfarlandsr]

New to the site, so bear with me... I have a 1993 Bronco with the 5.0. 170XXX miles or so.i was approaching a stop light, it started idling rough, like it was running out of gas and simply died. I've replaced the ICM on the fender, distributor, and the coil, still nothing. I have fire on the plug at the bottom of the coil, but NOT on the post at the top (where power is sent to the distributor). I also have a parts truck that is a 1994 with the same motor. All the parts from the road truck work fine on the parts truck, I even swapped the computers and still no GD spark! This has some Ford mechanics stumped. Any help would be appreciated. Thanks in advance.

 

[Rons beast]

Hey Tmac,  welcome

   First let's get to basics. The distributor signals the coil to "fire" or produce a high voltage, through the ICM by opening and closing the ground (-) to the coil. 

 Connect a test light between the + and - terminals of the coil.

Crank the engine. If the test light does not flash there is a problem in the primary circuit. If you changed the ICM and have 12v power to the coil,  the connections and wire to the coil is suspect. Also pull the dist. cap and be sure the rotor is actually turning during cranking. (Have seen the rotor and the dist. gear be a problem)

If the test light flashes everything in the primary ignition circuit is ok. (the coil has + power and is getting an intermittent timed ground). 

The next check is to see if the coil is producing a high voltage spark.  Disconnect the coil wire from the distributor and place it close to a metal ground on the engine. (CAUTION...do not place near any electric parts and don't hold it with bare hands!)

Crank the engine again and see if you are getting spark.

If you are not... the coil wire could be the problem replace it with a known good wire. If you still do not get a spark the coil is defective.

If you do get a spark...connect the coil wire back to the distributor and check for spark from a plug wire. ( use the same caution )

If you get spark from the coil wire , but not the plug wires inspect the dist. cap and rotor and your plug wires may have too high a resistance and need replacing.

(Thought not likely all went bad at the same time)

If you are getting spark from the plug wires your problem isn't ignition based.

Good luck