I have a 93 F-150, 5L with dual fuel tanks. Recently it started transferring fuel between the two tanks. I called Ford and had them check and it had not had the recall service. I took it in and now it seems to work fine. Can someone tell me what was done during the recall service? I understood that the recall included a new fuel pressure regulator and two check valves that would be mounted on the return lines along the frame. I got a new pressure regulator, but can't see that anything was added to the fuel return lines. Does this recall include added check valves and where do they mount them. Neither tank was removed, so the valves, if added, would have to be somewhere along the lines.

Just curious,

Fred
64 F-100
92 F-150
93 F-150

 

I thought it was a new selector valve.

 

I'm not sure where the change occurred, but the 1993s uses what are called "fuel delivery modules" (FDMs), one in each tank. The FDM consists of a low pressure pump, a high pressure pump and a check valve all in one unit. The check valve prevents cross flow and the fuel from draining back to the wrong tank.

With my problem, I started getting cross flow once in a while and it starting took much more cranking. I measured the fuel pressure while running and when the engine was switched off, the pressure went immediately to zero.

It's hard to see around things, but it looks like there are three fuel related lines running up to the engine. One is tee'd to both tanks and crosses over to the passenger side of the vehicle. I think this one goes to the carbon canister. It is somewhat rusty, so not as corrosion resistant metal. The other two lines follow the driver's side frame and go up to the fuel rail at the engine. One is the supply line (goes through the frame mounted filter) and the other is the return line from the pressure regulator. Down on the frame, the fuel supply and return lines split into two lines each, one of each pair goes to each tank. Both of these lines are clean metal (hae been this way since I got the truck) and are probably stainless or very well plated.

I think the problem with cross flow of fuel occurrs when one or both of the FDM check valves gets weak and lets the return pressure open it. I had heard that external check valves were added to correct this, but I sure can't see where any were added.

Fred

 

I need this repair for a 95 F150. It pumps from the rear tank into the front one.

 

If you call any Ford dealer and give them the VIN number, they can look up and see if the recall work has been carried out yet. If not, with the fire potential, they seem to want to do it as quickly as possible. Since it's a no cost visit, I'd do it soon. I've heard that there is a 12 year, 150,000 mile limit for the recall, but don't know if this is true.

Fred

 

The check valves are added to the fuel line where it attaches to the pump in the tank.
You could maybe see the check valves if you stick your head in by the frame and look above the tanks. Most of the job was done by feel.

 

Well that explains why I couldn't find anything in the fuel lines along the frame. I followed the fuel lines from where they branch off to the two tanks over to each tank, but didn't see anything that was added.

How do the fuel lines connect to the pump outlet on top of the tanks? Are they the same type of fitting as used on the fuel filter? It looks like it would be hard to disconnect and reconnect them, but maybe there is more room than I thought. I assume that the check valves have fittings that connect to the tank and to the fuel line.

Thanks for the info.

Fred

 

Yup they are fittings like on the fuel filter and a real painus in the anus to work with when they are above the tank.

 

Thanks for confirming their location. I think since it works ok after the recall, I'll forget about trying to find them. I had heard that the valves were added along the frame, so I was a bit curious when I couldn't find them.

Fred