As far as I understand it the regulator needs to be as close as possible to the fuel rail, as that is where the fuel pressure is most critical.
You do need the vacuum connection as it is used to stabilise the emmissions. Below is an extract I found on a website.
"The regulator's job is to keep the pressure in the fuel system to a constant 28 psi. It does this with a spring-loaded diaphragm that controls a valve. The valve, when opened by excessive pressure in the fuel lines, uncovers a fuel line that returns excess fuel to the fuel tank.
The vacuum connection is there to help reduce emissions during deceleration. During deceleration, the vacuum connection serves to open the fuel return valve wider, which reduces pressure in the system and prevents excess hydrocarbon emissions due to less fuel being injected as a result of the lower pressure in the system."
Cheers
Dave
|