Quote:
Originally Posted by Petar617
How much resistance should the check valves make when you try to open them manually ?? They are very easy to operate on my lift pump but they seem to close all the way. Is that good ?
|
The Valves that are in the Fuel Supply/Lift Pumps have a minimal resistance to them. the main resistance is moving the Fuel as the Fuel has weight and viscosity.
Vacuum is the absence of or lower pressure. The Fuel Supply Lift Pump creates a lower than Atmospheric Pressure (by way of the Hand Primer or the Piston and Spring inside of the Pump) on the Suction side of the Pump and it is actually the Atmospheric/Air Pressure pushing down on the Fuel that brings it into the Fuel Supply/Lift Pump.
The weight and viscosity of the Fuel causes resistance to flow and movement.
After that it is the Hand Primer or the Piston or a combination of the Piston and Spring inside of the Fuel Supply/Lift pump pushing the Fuel out of the Pump and the pressure of that Fuel is regulated by the Fuel Pressure Relief/Overflow Valve in the Fuel Injection Pump. On My year and Model the Pressure range is supposed to be a low of 8 psi and a high of about 18 psi.
So the resistance of the Fuel Supply/Lift Pump Valves is overwhelmed by the other forces created by the Pump.