How Do Ford Dual Fuel Tanks Work

General Motors Company has been a leader in vehicle innovation for more than 100 years. Ford is among the vehicle models that GMC produces. The company’s success is due to the quality of our vehicles and the ability to evolve with drivers’ preferences. Dual fuel tank in Ford vehicles is one of the efficient innovations by GMC.

 Although no longer common, you can still get the dual fuel tank system in Ford’s super-duty models. But how do Ford fuel tanks work? To get this question’s detailed answer and explanation, continue reading this article. You will also find out the reason why Ford adopted the dual fuel tank system. Let’s get to it.

Why did Ford do dual fuel tanks?

Ford adopted the dual fuel tank system for efficiency. The earlier models had small tanks hence limiting drivers on fuel carriage. An introduction of two tanks meant more fuel for the trucks and longer operating hours.

Other than that, the two tanks enhanced weight distribution. The two tanks helped in mitigating balance loss when the trucks made hard turns. This feature gave drivers more confidence by reducing the worry of running out of gas in remote areas and improved safety.

How do Ford dual fuel tanks work?

Ford truck with the dual fuel tank system has a primary and secondary tank. These tanks are connected with two balance pipes, through which the gas moves from one tank to another depending on the level of fuel.

In this system, one pipe supplies gas to the engine while the other from the fuel trail.  Note that the tanks work simultaneously. As you drive, fuel moves from the primary tank through the discharge line. The secondary tank replaces the energy used in the primary tank.

When you turn on the ignition, the fuel pump starts operating. The process continues unless the engine stops or its speed drops below 120 ppm. On turning it off, the Power train Control Module shuts the fuel pump off in a second.

The dual fuel tank system design

This system is designed with two tanks in series and parallel. The series design sets the fuel pumps in a standard fuel line. On the other hand, the parallel design functions by the pumps operating in two independent fuel lines merged at the fuels system’s Y connection.

This system has a sender assembly that handles the switching of gas through valves. The system has the following support components:


The fuel reservoirs prevent fuel interruption should you find yourself in extreme truck maneuvers while on low fuel. These reservoirs are in-tank and composed of the Fuel Delivery Assembly.

Screens and filters

There are four screening or filtering devices. These include the fuel intake sock, filter screen on the fuel rail port of the injector, and the Schrader valve. On the fuel inlet side of the pressure regulator is another filter screen that plays a part in pressure regulation.

Shuttle selector valve

This valve controls the fuel pressure. It opens the return line when the pressure on the shuttle diaphragm exceeds the opposing spring force.

Supply check valve

This valve opens only when the pump’s outlet pressure exceeds the valve spring force pressure. When you stop the engine, the supply check valve closes to control the fuel line pressure and maintain the pump prime.

Venturi jetvalve

When a high-pressure flow from the pump, the system diverts it to run the venturi jet pump, the pump then draws fuel from the fuel tank to the assembly. The process maintains fuel supply to the pump during steep vehicle altitudes while on low fuel.

The venturi jet valves inlet has a nylon filter that prevents dirt from entering the fuel system.

Fuel pressure regulator

This regulator operates using a diaphragm. The relief valve is attached to the gas supply manifold system of the fuel injectors. It controls the fuel compression provided to the injectors.

The fuel pressure regulators diaphragm operates by one side sensing the gas pressure while the other is linked to the intake manifold vacuum. The regulator establishes tension by a spring preload exerted on the diaphragm. In doing so, it put one side of the diaphragm at equilibrium with the manifold vacuum to keep endless fuel pressure.

What are the dual fuel tanks problems?

Ford dual fuel tank says two main problems. These are fuel cranking and fuel transfer even when the vehicle is off. The others, though not familiar, are the fuel tank selector switch and overload fuel tank. In some instances, when you switch to the front tank, you will hear a click from the tank selector valve.

If you happen to face any of these problems, you can fix them with the solutions below.

Solutions to the dual fuel tanks problem

You can use the recall kit from Ford, which prevents the fuel cranking and transfer even on stopping the truck. The kit has two in-line check valves and a fuel pressure regulator that prevents fuel flow through the supply line.

Despite the regulator not reducing the fuel circulation from one tank to another, it will help with the long cranking time. If you suspect that the fuel pumps are malfunctioning, it will help put out enough pressure to free the return valve. Take caution not to put out stress on the other tank.

For the selector valve, you should connect the fuel line to the pump and alternate the valve. In doing so, your truck will run fine, and it will also help you check the fuel level in each tank.

If the rear tank is filled, it flows to the from one and might be overfilling. Should you find your Ford with this problem, you should reinstall the selector valve. Alternatively, you can replace the tank’s fuel pump.

Key Takeaways

When Ford introduced the dual tank system, it came with its fair share of advantages. These included the stability and confidence of drivers even when driving in remote areas. Despite slowing the production of trucks with this fuel system, there are trucks still with it. Should you come across one or possess one, you should use this article to inform how the system works.


Hi, I'm the initiator and writer of this blog. Cars were and will be my first love, and my favorite hobby, that's why I decided to start this blog and write about my discoveries and techniques to improve my cars or repair them.