1989 F 150 3006 5 speed. Replaced Ing module, replaced fuel filter checked good pressure supply return clear. Was driving this morning died. Got it to fire enough to get safe place.Would just sit crank.So now it fired up ran a few seconds then died just sits and cranks. What I overlooking??

 

It always helps when we have some idea which direction to pursue.
We don't know if there is a fuel supply problem, an ign syst problem or an electrical problem.
If you shoot a 2 second shot of carb and choke cleaner into the air cleaner intake and the engine fires up and runs , fuel supply problem.
If it does not start we need to check for spark at either the coil or any one of the spark plugs. If we have spark , air and fuel the engine should start. If no spark ,have ign syst problem. That could include for that particular year, the coil, the ign module , the pick up coil in the dist or possibly the computer.
Electrical problems enter the picture and that can get a little lengthy to explain.
If you try the tests described , that should provide some direction.

 

Thanks fires up with shot starting fluid,Then it will fire up run for 45 seconds to a min shut off like its fuel issue let it set few mins fires up 45 seconds to a min dies again.Can go from idle to full no problem while running.Replaced fuel pump relay today still same so last thing I see before replacing the young lifetime warranted pump is the vac operated pressure regulator. Replaced ignition module first,then fuel filter. Then Cap and rotor.yesterday Fuel was under high pressure at filter, pump running here it loudly all returning spraying into tank. Replaced pump about a year ago also then went ahead replaced idle control and throttle position control and relays then. Has new coil wires and all new internals in distrib. Just running out of parts to replace. Hoping not the engine box.Going to run trouble codes may replace pump. Was running great felt like it was choking out dead pedaling when it quit on me started this. 815,000 so just trying to get this old 89 to a million. Thanks again for responding.

 

It does sound like a fuel supply problem. Many times a fuel pump is replaced because fuel pressure/ volume is low and the pump could be defective, but a poor electrical connection is really the culprit. Make sure, the power supply and ground for the fuel pump are good. Just looking at the connections ,as you know, does no good. They have to be physically checked. Guessing at fuel pressure falls short , use a pressure gauge.
They were a tough bird in those years , after 800,000 miles what's 200,000 ? You can do it!

The "box" provides the ground for the fuel pump relay based on an RPM signal.
If you provide power to the pump directly , you can by-pass the box! Watch out for some poor quality aftermarket pumps.

 

Thanks Bought the lifetime Airtex in tank pump in spring. Just hate the thought of that again sitting 3/4 tank This truck was staring right up all the time no problem 2 crank all these years then went to having hold the pedal to floor crank a bunch before fired up. That stopped resumed her normal 2 cranks.finally just did this. Got a Almost Fresh SVO 302 with B&M Trans and torque converter Calling me. It is sitting in my 87 Ford Ranger toy was building.Had got old Last narrow Bronco was converting it to 4X4. So if the vac op regulator stuck would that stop proper fuel flow? This one stays vacuumed even sitting not running was going to be my next move had never replaced it yet.She been so dependable and trusty all these years been replacing a old part once a month just reward her. lol Just love how dependable cheap this 300 6 5 speed has been. Have a great day.

 

Vacuum op regulator stuck ? Used to hear the pump kick on pressure up and stop before starts now pump is not stopping hear it all returning to tank? All elect connects fine.