How does the valve on a fuel return line work?
On the exit side of your fuel rail, you have a mechanical valve. This valve is set to maintain a certain pressure, (rail pressure) or sometimes a certain pressure difference (between rail pressure and intake pressure). If the pressure is too low, the mechanical valve restricts the flow leaving the manifold, increasing pressure.
Why is there no pressure on the fuel rail?
If the pressure at the exit side of the fuel filter is normal and yet the pressure on the fuel rail is essentially zero, it’s possible the fuel pressure regulator has failed wide open, essentially preventing sufficient pressure from building.
What happens when a fuel regulator gets stuck?
When the fuel pressure regulator gets stuck and builds up more pressure then it should; it’ll cause the injectors to deliver too much fuel; causing a rich mixture (high pressure) condition. The easiest way to test fuel pressure regulators, is with the use of a fuel pressure gauge.
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.
Where is the return line on a fuel pressure regulator?
Also, a return fuel line, from the fuel pressure regulator. This return line is located, downstream of all the injectors. Most fuel pressure regulators, use a diaphragm and spring combination within its housing. Also, with a vacuum source on the top side of the diaphragm.
If the pressure at the exit side of the fuel filter is normal and yet the pressure on the fuel rail is essentially zero, it’s possible the fuel pressure regulator has failed wide open, essentially preventing sufficient pressure from building.
When the fuel pressure regulator gets stuck and builds up more pressure then it should; it’ll cause the injectors to deliver too much fuel; causing a rich mixture (high pressure) condition. The easiest way to test fuel pressure regulators, is with the use of a fuel pressure gauge.
What happens when you shut down the fuel return line?
During these moments, the fuel pressure regulator, temporarily, shuts down the fuel return line. As a result, boosting up the fuel pressure. So, using this information, the computer decides the strategy, that will result in the best performance of the engine.