Sage-Tips

Can you block off a fuel return line?

Any fuel going through the return line is simply fuel your engine did not need/could not use. Blocking or restricting the line only increases fuel pressure at the injectors. Blocking the line results in the fuel pressure just being the maximum the pump can push.

Does fuel need return line?

When using a Return Style Fuel Pressure Regulator, it must be able to return 100\% of the fuel back to the tank. The Fuel Return Line should be at least the same size, or one size larger than the supply. The return line should direct fuel close to the bottom of the tank and away from the pickup.

How does the fuel return line work?

Return-Type Fuel Systems A return-type fuel system is one that is designed with a fuel pressure regulator that diverges the fuel pressure based on the power of vacuum suction from the engine’s intake system.

Why is there a vacuum line on a fuel pressure regulator?

The fuel pressure regulator uses manifold vacuum to increase fuel pressure during hard acceleration, and the manifold pressure is low because the throttle plates are fully opened.

How do I know if my fuel return line is clogged?

Strong fuel odor, engine misfires, and decreasing power If there is any sort of issue with the fuel hose, either a leak, or some sort of kink that blocks the flow, it may cause the vehicle to produce an excessively strong fuel odor from the engine.

Do I need a return line with a fuel pressure regulator?

Advantages. Requires no fuel return line and fittings from the regulator to the fuel tank. This reduces weight, complexity (routing a return line can prove to be difficult), and expense. Multiple regulators (set at different pressures, such as with a nitrous oxide system application) may be used from one pump.

Does a fuel return line have pressure?

There is NO WAY there is that much pressure in a return line unless there is a problem with the line (blockage, kink, etc). If the tank was full of water, it would cause 0.25 PSI of pressure in the fuel line if it had 7″ of fuel above the return.

What is the pressure in a fuel return line?

With a return system, the base pressure is set with the engine off, but the pump running. For a GM, this pressure is usually set to 58psi (factory fuel pressure in the rail). The vacuum/boost referenced regulator will help to change the pressure in the rail based on the pressure in the manifold.

Can a fuel pressure regulator stuck open?

Once you have triggered the fuel pump, and you still have low or no fuel pressure, it could mean the fuel pressure regulator is leaking or stuck open. However, if the fuel pressure is high, it could mean the fuel pressure regulator is stuck closed.

Will a fuel pressure regulator work without vacuum?

When fuel pressure at the regulator is high enough, it overcomes the spring’s pressure without any vacuum assistance. However, at idle, the engine’s vacuum is high and assists the valve’s opening. When the engine is under acceleration, fuel demand is high, and the intake manifold’s vacuum is low.

What happens when your fuel line is clogged?

When a fuel line is blocked, fuel does not flow properly into the engine; as a result, it overflows and goes back into the fuel tank. When this happens, it could leak and come into contact with an ignition source, such as the engine, and cause smoke. If this goes unnoticed, this could lead to a fire.

What happens when you bypass fuel pressure regulator?

With a bypass style regulator, fuel enters through the inlet port (A) and travels past a fuel bypass valve/fuel return line port (which governs fuel flow and pressure) (B) and then is distributed through an outlet port to the carburetor or EFI fuel rail (C).

What happens if the fuel return hose is blocked?

If the fuel return hose becomes blocked or kinked it may cause the carburetor to flood from excessive fuel or pressure buildup. A flooded carburetor may cause engine stalling and hard starting until it is cleared, or enough fuel has evaporated. 3. Fuel leaks Another symptom of a potential issue with the vehicle’s fuel return hose is leaking fuel.

What is the difference between a blocking and non return fuel regulator?

Non-return style regulators are characterized by their lack of a fuel return line from the regulator back to the fuel tank. With a blocking style regulator, fuel enters through the inlet port (A), travels past the fuel control valve (B), and then is distributed through an outlet port to the carburetor.

What happens if you put the fuel regulator in the tank?

Relocating the regulator to the fuel tank eliminates the circulation of fuel between the engine and tank so the fuel stays cooler. It also simplifies the fuel system plumbing by eliminating the return line. Another advantage is that putting the regulator in the fuel tank keeps it away from engine heat and extends its life.

Can a bad fuel pressure regulator cause a misfire?

There are also many causes of engine misfires. It can be a problem in the spark plug or the ignition coil. A fuel injector problem can also cause engine misfires. It is also one of the symptoms of a bad fuel pressure regulator. A problem with this device can lead to low fuel pressure.