Bad Fpr

[civic619]

Quick question about the FPR. If vaccum is applied to the regulator, it should open up correct? and if pressure is applied, it should be closed. And it remains closed static, right?

 

[steve]

Not sure what you are trying to say.
The basic operation is the FRP return valve stays closed untill the fuel pressure exceeds the spring pressure. The reference from the manifold modifies the spring pressure by acting on the diaphram. Positive pressure (boost) works with the spring to hold the return port closed raising the fuel pressure. Negative pressure (vacuum) works against the spring to lower the fuel pressure. Trying to open the port just using vacuum to the nipple without fuel pressure pushing on the other side might damage the FPR.

Steve