Ok, bought this truck back in march. 1990 F250 4x4,5.8l,ZF5 with a 1993 motor. (don't know if that makes a difference but thought i would throw it in there) After about 3 weeks of driving it, it would die if you let it idle longer than about 10 minutes if the truck was already warmed up. It wouldn't refire right away. Let it sit 10 minutes and it would fire up. Then one day it died and i couldn't get it restarted at all. could'nt here the fuel pump turn on. so had a buddy bring a flatbed and we took to the shop he looked at. Also noticed fuel tank had started leaking. I can only use the front tank because the guy i bought it from said the back tank leaked. The next day he tryed it and it started right up. the only codes were one for egr and i got that before when we checking why it idled so rough had that all checked out and put on a new egr sensor. Replaced air idle control. so we put a tank in it took on a 60 round trip and everything was fine. so i thought i would drive it to work the next day. It died on the way home couldn't get it to refire. Had it towed to shop in town. next day it started again. He checked fuel pressure and it was only 10 to 15pounds. but he thought his gauge wasn't working because the truck was still running.he put about 20 miles on it and it was fine. I took it to work the next day and it died on the way to work. Had it towed to a different shop. Put in brand new Ford fuel pump and 535 dollars later took it home. No problems in about 700 miles then last Sat night went to a friends house for about an hour and couldn't get to start. took his car home because i had my 9month old son with me. sunday morning took his car back and it still didn't start. had the wife pick me up. Friend was home in the afternoon were going to pull it back to my place tryed starting it just for fun and it fired up. took it home and didn't drive it till yesterday. I'm milking cows for a guy by a nearbuy town and was going to take him a round bale of hay because he was out. got to town about 10 miles and stopped at the gas station for a quick sandwich jumped in the truck and it started started backing up and it died wouldn't refire. Walked over to the shop across town, He's the one that put the new pump in, said if i had any problems he would cover it. pushed the truck over there and the were going to check for spark. turned the key and it fired right up. WTF he said to tap on the fuel solinoid to see if that helps when it won't run. when it won't restart i can't here the fuel pump run. he said to tap on that solinoid to see if something in there is sticking. Sorry for the long thread but i wanted to tell all the information to see if any of the masters on here can diagnose this problem as it's really starting to get on my nerves.

Thanks in advance

 

If it were mine I would replace the fuel pump relay and possibly the inertia switch. Both are prone to failure. Check the wiring connections and everywhere there is a connector pull it apart and make sure it is clean and not corroded. I doubt a short problem else it would be blowing fuses. Intermittent problems like this make for bald people. jim d

 

I think as well probally fuel related, when it runs good it runs, when it wants to kill then it sounds like it kills quickly. As Jimdandy said, check all connections, and grounds. Possible could be the fuel pressure Regulator? check fuel pressure again with guage on the shrader valve on intake rail in the back behind upper intake manifold and see what it reads when engine running and after shut off, and what it holds at after 10 min. Also, your truck is a 1990 and uses the older type low press. in tank pumps with a high press. pump on the rail/frame by the crossmember, (if I remember correctly.) The engine is a 93 and uses the in tank high press. pumps only. May not matter anyhow, as long as it has adequate pressure to the press. regulator then its ok. Just an idea for thought. Another idea if it is electrical, then would or may be the ignition module on the fender (1993 engine) or a bad ground or weak ground when engine gets hot, and resistance takes over. Good Luck, Doug.

 

There is no rail pump on this on just the pump in the tank. I thought that to because i read on there a pump on the frame but one mechanic told me that that's only on the half tons with the 302. The pump is putting out 35 to 40 psi when it was put in. I don't have the equipment to check it myself. but i will look at the fuel pump relay. That is what he was showing me yesterday. Said there was contact points in there and they get sticky with age.

 

what side is the ignition module on?

 

he also was looking for the inetria swith but couldn't find it. the book he said on a 90 is was on the drivers side above the brake pedel. he didn't see it though.

 

Yeah, I agree, the pump relay can get flaky & cause this. They're only about 5 bucks so why not change it?

Testing the fuel pump circuit is very simple, so i'm surprised that this has gone on for so long.

If the new relay does'nt fix it, you need to do some testing.

To keep the pump circuit energized so you can test voltages see this link. www.superhighoutput.com/tech_view.php?id=5

Connect that jumper, grab your wiring diagram & voltmeter & find the problem.

TAke a look at your wiring diagram, odds are the wire from the pump relay to the inertia switch is orange/light blue.

Thats the first place to test for voltage when it wont start.

 

d_stange the ignition module on your 1993 engine would be on the drivers side fender, just below the hood hinge area. It is attached to the fender. I changed mine few weeks back. The module is first mounted to a heat sink aluminum finned thing. I found it easier to remove the entire unit from the fender, then remove the module from the haet sink backing. Sounds like you may want to try the relay as mentioned above first, and eliminate the fuel side of it first to keep it simple and cheap.

 

How about the fuel pump pressure valve? I had one go bad and caused simular issues. Mine was on the fuel rail on top of the throttle body. It had dumped 3 gallons of fuel into the oil pan before they figured it out. I guess I'm lucky it didn't start then. might have just blown the whole garage up.

 

well it died again last night. at least i made it to where i was going. It's sitting on the farm i was doing chores at. ran good over there about 12 miles. Was going to use to put some hay bales in and bring them to the barn. Tapped on the fuel relay wiggled wires and nothing. Called a buddy and he ran to town to get a new fuel relay. NOTHING. wouldn't start so after i got done with chores he gave me ride home and gave me s**t for driving a ford. At least it's on 2 miles to the shop where they put the fuel pump in. He said if the fuel pump didn't fix it when i took it in there he said it would be on his dollar. He better stand behind that because i want the POS fixed.

 

Well the mechanic wanted to charge me 40 buck to tow it 2 miles so i said forget it and i went and rented a trailer and hauled it home with my other truck. I'm going to put a new ignition module on it this week sometime and see if that helps. I couldn't get a pop out of it this weekend so something is really toast now. it's a 100dollar part but if it doesn't work i can rule it out. If that isn't it i suppose i'll have to start checking every wire on the truck. Hee Haw...

 

That ignition Conrol Module is only 40.00 dollars at Checker Auto. Part #FF411.
I looked up for a 1993 engine 5.8L.

I could not figure out how to paste a linke or picture of that page.
I still dont know what could be the problem with not starting. Hope do not have to throw parts at it till broke. I did that with my truck this spring, and is working goood now, except for slight exhause leak that is a bare. Good luck,,Doug.

 

i don't know what else to do. The mechanics are guessing so i figure i can do the same thing and not spend to money on labor.

 

Perhaps change the Fuel Filter as well if you have not done it yet, when you changed the fuel pump.

 

Hey Stange, I did some looking and had a question. When you had the engine swapped or when you bought the truck and was already done, what distributor does it have? The 1990 5.8L has the Ignition module mounted on the Dist. where as the 1993 engine would have a remote fenderwall mounted Module. Was 1990 dist. put on the 1993 engine? or did you or someone re-wire for the remote module wiring and spout dis-connect stuff? just wondering if this could be something to look at.