1989 F250 4X4 5.8 Liter No fuel at fuel rail.

[paul begosh]

As it would be I have one of the most complicated fuel systems ever manufactured by ford. I have dual tanks, Two in tank low pressure pumps, 1 high pressure pump on frame rail, dual reservoir, selector switch on dash, etc, etc, etc. Everything is new. I completely restored this truck from the ground up. 35 k invested. I got disgusted as well as life got in the way and it has sat for 5 years. I've been troubleshooting the EEC and fuel pump relays (both new and completely rewired into the stock harness). I'm getting fuel at the discharge side of the fuel filter. Its a straight shot to the fuel rail from there. Nothing. I had let someone else do some troubleshooting and he had changed the pressure regulator. Despite it being new, I'm about to run to the parts store and change it out. What else could it be? But the bigger problem is that when I do get it running, it runs rough, and when I try to increase RPM's it stumbles, has no response and backfires and pops. I've been suspecting a MAP sensor wiring issue and started to run new wiring but now finding this fuel issue I am beginning to think it is fuel related. I have new tanks, sending units, supply and return lines are new or clear, new reservoir, HP pump, filter, injectors, you name it. The Ignition system and distributor are all new. I've removed the body wiring harness and the engine wiring harness and checked each wire for continuity. New coil, plug wires and plugs, New PCM, I've done nothing but throw money at this truck. Its a money pit for sure. I've got the motor bonded to the body and frame. I've bonded each fuel tank to the frame. I used heavy duty welding leads with compression connectors to bond everything. So I don't have a bad ground! Help me please I'm losing my sanity. Thanks in advance. Skully

 

[Fellro]

The second pump is the true pressure pump, the ones in the tank are low pressure transfer pumps. If the high pressue pump has failed, you will have troubles as it needs the pressure to get proper spray as well as simple delivery. The regulator is basically a spring and a diaphragm. If you don't have enough pressure to overcome the spring, you will not have fuel delivery. Both pumps (selected tank and high pressure) should turn on for a few seconds after turning the key on.

 

[paul begosh]

Thanks for your feedback, I pulled the pressure regulator and turned on the key.. I am getting a good volume of fuel for about a second. and it stops. which in supposed to operate that way when the EEC grounds out the relay. I did find out that someone that had done work on my truck put a later model fuel rail with a different pressure regulator on it. I had to order a regulator for a 1995+ that had the bolt configuration to mate the regulator to the rail.??? Don't know why he did this. I will install the new regulator and see if I get fuel to the rail. If not I'll fall beck to the low pressure pumps in the tanks as I know the HP pump on the frame rail does indeed work and pushes fuel through the filter...Thanks again Fellro.

 

[Fellro]

It will run on the high pressure pump alone if there is enough fuel in the tank. I actually have one doing that right now, the in tank pump shorted out so bad it smoked the wiring.
The later trucks did away with the 2 pump setup and went to a single in tank pump and check valve so maybe the later regulator is the issue? Not certain but perhaps could be. Having fuel at the rail seems to be saying no to pump issues.

 

[dustybumpers]

the fuel delivery modal is bad. it's the part in the frame where the 4 lines come in, 2 lines go out, then it goes to high pressure pump.
here is a picture of the system when I was building my F 350



It is the round can looking thing to the left. You will find it is not rebuildable, and is filled full of dirt.
It also hates ethanol. It also hates sitting. I have since upgraded to 94 fuel system, 2 intank pumps, new wiring harness, 92 f 350 ecm. Tired of paying $300 a year for fdm's

 

[paul begosh]

Thanks for the input, I'll have to look into that. I did replace it when I rebuilt my truck. It has to be about 6 years old or so but the truck has indeed been sitting for quite some time (about 5 years). The whole ethanol thing seems to be worth looking into.

 

[paul begosh]

On another note. How could that fuel delivery module affect there being no fuel at the fuel rail if I am getting fuel through the HP pump, filter and up to the mounting plate at the fuel rail? I installed the new pressure regulator today and despite getting fuel to the rail assembly with the pressure regulator removed; when I installed the pressure regulator and cranked the motor over I still had no fuel in the rail? I'm starting to suspect some sort of blockage in the rail unless there is validity in your comment that it is the fuel delivery module. Listen bro, I'm not arguing or challenging your knowledge. I'm throwing the question in there because I don't have the answer and I'm trying to understand this issue.

 

[dustybumpers]

Because the fdm is shutting off the fuel flow. the high pressure pump can't supply fuel the the rail if it can't pull it thrpugh the modual.


Ok, so let's explain what this thing is.
there are no check valves in this fuel system.
so when you switch from rear to front the fdm switches where the fuel returns, and front to rear, where it returns.
when it decides to crap out and shut down it goes in the middle and will not allow fuel to flow in either direction.

Basically the hpressure pump is just sucking nothing and giving nothing to the rail.
Ford realized this flaw and redesigned the system in 90. then again in 93.


This is what the fdm looks like inside. Like I said before You can't fix it, and I can guarentee it is your issue.

Just for S& giggles, take the supply line from the lift pumps on the back side of the FDM, let them hang over a bucket.
Hit the key. see if fuel comes out of both lines when switching tanks from your lift pumps when cycling the key.
My bet is yes.
hook the lines up, cycle the keys again with the lines off the other side of the fdm, my bet there will be no fuel either tank.

 

[dustybumpers]

On another note. How could that fuel delivery module affect there being no fuel at the fuel rail if I am getting fuel through the HP pump, filter and up to the mounting plate at the fuel rail? I installed the new pressure regulator today and despite getting fuel to the rail assembly with the pressure regulator removed; when I installed the pressure regulator and cranked the motor over I still had no fuel in the rail? I'm starting to suspect some sort of blockage in the rail unless there is validity in your comment that it is the fuel delivery module. Listen bro, I'm not arguing or challenging your knowledge. I'm throwing the question in there because I don't have the answer and I'm trying to understand this issue.

So I assume a small amount of fuel is coming through, but not a measurable amount.
do the test I said in previous post

Also I am NOT your BRO. I find that comment to be disrespectful and unnecessary
With that said Done here. Good luck. Hope you solve your problem

 

[Bohemouth]

As it would be I have one of the most complicated fuel systems ever manufactured by ford. I have dual tanks, Two in tank low pressure pumps, 1 high pressure pump on frame rail, dual reservoir, selector switch on dash, etc, etc, etc. Everything is new. I completely restored this truck from the ground up. 35 k invested. I got disgusted as well as life got in the way and it has sat for 5 years. I've been troubleshooting the EEC and fuel pump relays (both new and completely rewired into the stock harness). I'm getting fuel at the discharge side of the fuel filter. Its a straight shot to the fuel rail from there. Nothing. I had let someone else do some troubleshooting and he had changed the pressure regulator. Despite it being new, I'm about to run to the parts store and change it out. What else could it be? But the bigger problem is that when I do get it running, it runs rough, and when I try to increase RPM's it stumbles, has no response and backfires and pops. I've been suspecting a MAP sensor wiring issue and started to run new wiring but now finding this fuel issue I am beginning to think it is fuel related. I have new tanks, sending units, supply and return lines are new or clear, new reservoir, HP pump, filter, injectors, you name it. The Ignition system and distributor are all new. I've removed the body wiring harness and the engine wiring harness and checked each wire for continuity. New coil, plug wires and plugs, New PCM, I've done nothing but throw money at this truck. Its a money pit for sure. I've got the motor bonded to the body and frame. I've bonded each fuel tank to the frame. I used heavy duty welding leads with compression connectors to bond everything. So I don't have a bad ground! Help me please I'm losing my sanity. Thanks in advance. Skully

Start with the emergency inertia switch L kick panel. Then move to filter n tank selector. Then to fuel pumps I'd selector is working.. happy hunting.

 

[dustybumpers]

Inertia switch 85-91 is on the inside firewall above the wiring harness

 

[paul begosh]

Well it's been quite awhile since I checked this thread. But I'd like to thank you for the detailed description and pictures of your theory with the fuel distribution module. Hope my calling it a theory doesn't offend you. Thanks again dusty bumpers...sir...

 

[paul begosh]

Additionally, I have my inertia switch jumped out. It's one less part of the equation....