I'm so close to getting all these stupid bugs worked out. Heres the schpeil:
I drove the truck last thursday and everything ran fine. I got in Friday morning and it would turnover but wouldn't crank. Fuel pump is coming on and getting fuel to the engine but no spark. Its a 1991 f150 xlt lariat 4x4 with the 5.0L. my best guess is to replace the distributor and TFI module. anyone have any experience or suggestions?

 

Yes I have experience and a suggestion. Most likely the ignition module on the side of the distributor went dead. You will need a special tool to remove and reinstall the ignition module. On a 5.0 you will probably need to turn the distributor to do this. Be sure to make some marks before you loosen the distributor hold down bolt so you can get it close to back in time.

Don't forget to apply the special heat sink grease to the side of the new module when you install it.

 

You hopefully just made my day. I didn't know if I needed to replace the entire distributor or just the TFI (ignition module) or If i needed to replace the ECM.

 

The ignition module going dead is the most likely thing on a 1991 or older Ford. Pretty common, just playing the odds, but a very good bet.

 

Could also be the ignition coil or the PIP inside of the distributor.

 

Advanced Auto (and probably others) can check your module to see if it is any good once you get it out.

 

And the results are in.... bad ICM. Replaced it Friday afternoon and it fired right up.

 

I have the same problem and replaced fuel relay, EEC relay, coil,ignition module and finally distributor. Thought for sure it would fire. But no spark from coil wire still. What am I missing??

 

Have you checked if you are getting power up to the coil, through one of the small wires that hook onto the coil? You have to turn the ignition switch on while checking this. Don't forget to turn the ignition switch off after checking this.

What vehicle are you working on YEAR and ENGINE?