No not yet.
With the key on ground and then remove the ground from pin #6, does the fuel pump relay click?
Image of fuel pump relay below.
I do not know yet.
May have bad fuel pump relay, tell me if it clicked above.

Image of fuel pump relay:


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Was the fuel pumps running all the time pin#6 was grounded with the key on and you got zero pressure?

 

Yes it did, both pumps depending on the selector switch setting.

Should the click be loud? I think I could here it but I'm gonna try again with cover off the fuse box.

 

Yes it clicks, if you put your finger on it you can also feel it and yes zero pressure the entire time pin 6 was grounded.

 

I will ask this, are you sure you have fuel in the tanks?
If so your fuel filter may need to be changed again, I think you said you changed it above.
If it is not the fuel filter then either the fuel pressure regulator is wide open or both fuel pumps (FDM) are bad.
If the fuel return line from the fuel pressure regulator has a flexible line on it see if you can squeeze it as you run the pumps and see if you get any pressure.

 

The gas gauge says half a tank in the front tank. I can try putting in more gas. I think there is a flexible line near the tank. I will try clamping the hose off and see if I can build pressure. The regulator is up at the back end of the fuel rail isn't it. Can they stick full open? The filter hasn't had a full tank of gas run thru it so I would guess it is ok. Front tank was just replaced this winter with new from local Ford dealer.

 

You have to clamp the return line for both tanks to tell that is why I said by the fuel pressure regulator.
YES
I have not ran into any FPR sticking open yet but there is not much left to check and anything is possible.

 

OK I'll try pinching it off by th FPR if I can. If there is no flexible line up there I think there is one before the T for the front tank along side the filter. I will try in the am as it is almost 10 pm here in Maine. Thanks for all your help.

 

Pinching the line didn't make a difference. I took the filter out and there is plenty of gas in the line, no pressure tho. I ran the pump with the line going into a gas can and it does pump fuel. What next?

 

OK I got pressure. Put the filter back in and reconnected the fuel line. I can get almost 40 psi while grounding pin 6. When I stop running the pump pressure drops right down to 0. Truck still won't start.

 

Sounds like you have bad valves is both Fuel delivery modules, The pumps may be OK inside the modules but they can not overcome the open valves in the other tank.

I have never heard of any thing like this happening before.
The only thing I know you could try is to clamp shut the pressure line for one tank and select the other tank and see if you have pressure and it will start.

 

This truck does not have the FDM's. It has the sending unit float and seperate pump in the tank. Does this setup also have a valve that could be malfunctioning?

 

A 1994 truck has FDM in side the tanks and the fuel pump is inside the FDM.

The FDM:

OR


Your Fuel System:


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Not trying to argue the point but when I changed the tank that is not what was in there. Could it be a previous owner changed it with the other setup?

 

Do you think it would be worth pulling the one from the rear tank and trying it in the front tank with the rear blocked off?