I have a 91 with 4.9 and E40D transmission. I had done a tune up on the engine it was running great. I shut it off to change the inline fuel filter, I pulled the relay for the fuel pump and started it up to relieve the line pressure. Changed the filter, put the relay back in, cycled the fuel pump a few times and can't get it to start. I have been trying to get it to start for a few days now. There is fuel pressure at the schrader valve, the fuel pump it working, other than that I can't figure it out.
Did I mess up by pulling the relay and starting it up to run the fuel out? Any help would be great as I am out of ideas.

 

Check the wiring under the relay sockets.
If OK check for spark.

 

Shoot a little starting fluid in the throttle body and see if it will start that way. If it does, your problem is fuel delivery. If not, it is likely electrical (i.e. no spark).

 

X2. Probably air. Did you try cranking with your foot to the floor?

 

Sorry for the late response, been running like crazy with the holiday.
I had about 10 free minutes and had a chance to check for spark since it was the only thing I haven't done.
No spark.
I have no idea where to start on this, just (last weekend) replaced the coil, rotor and cap, plugs and wires. truck was running rough before, after the "tune up" it was running great. Starting quickly, idling smooth, no hesitation. I don't know what I could have done to disable spark by changing a fuel filter.

 

Put the old coil back on, recheck for spark.

 

I had the same thing happen to me. It turned out to be the pip sensor inside the distributor. There should be procedures to check it on here somewhere.

 

Thank You! I didn't troubleshoot, figured for $80 it was the only part of the ignition not new so I just replaced it and hoped for the best. It was the distributor, we are now running again. No more hard starting when warm either.Thanks again.