What happens when the pressure is too low on a fuel return line?
If the pressure is too low, the mechanical valve restricts the flow leaving the manifold, increasing pressure. If the pressure is too high, it allows more flow to escape, decreasing the pressure.
What are the symptoms of a bad fuel return hose?
Usually a bad or failing fuel return hose will display a few symptoms that can alert the driver of an issue. One of the first symptoms of an issue with the fuel return hose is an excessive fuel smell.
How does a fuel return line work in an old car?
Older cars didn’t have a return line very often. There was a fuel pump and a simple float valve in the carburetor that let fuel flow as it was needed. The downside to this setup is that engines get hot. When gasoline gets hot it turns into a gas.
How does a returnless fuel pump system work?
Mechanical returnless systems simply relocate the pressure regulating valve into the fuel tank, directly after the pump. Electrical returnless systems regulate the fuel pump speed in order to control the flow and pressure.
Why does returnless fuel injection eliminate the return line?
Unfortunately, this carries a lot of engine heat back to the fuel tank and increases evaporative fuel vapor emissions. 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.
Why is the fuel pressure in a return system not variable?
A downfall of return systems is the fact that they circulate fuel through a very hot engine bay, ultimately carrying that heat back into your fuel tank. A return style system that isn’t variable will maintain a certain pressure inside the rail, regardless of what is happening in the manifold.
How can you tell if your fuel pump is dead?
Of course, there could be other explanations for your engine’s failure to start besides a failed fuel pump. To confirm that your pump has failed, check the pressure in your fuel lines with a fuel pressure gauge; if it reads zero, then your pump is likely dead.
How does a return style fuel injector system work?
Return style systems hold a big advantage in that with a vacuum/boost referenced fuel pressure regulator, the system can maintain a CONSTANT effective fuel pressure, which can extend the range of fuel injectors and help them function at lower fuel demands as well.