fuel lines!!!

[skierdude494]

doing the rb25 motor swap and am a little confused on the 2 fuel lines on the left side which one is the return? any help would be greatly appreciated

[pdvorak]

the line that goes to the fpr(fuel pressure regulator) is fuel in, and the other one is the return.

[Darius]

NO. Exactly the opposite of what he just said.

The supply line comes from the fuel filter and goes to the line that feeds the rearward end of the fuel rail. The fuel then passes through the fuel rail to the fuel pressure regulator. Whatever is bled past the FPR goes to the return line.

[Bwana]

NO. Exactly the opposite of what he just said.

The supply line comes from the fuel filter and goes to the line that feeds the rearward end of the fuel rail. The fuel then passes through the fuel rail to the fuel pressure regulator. Whatever is bled past the FPR goes to the return line.

Yep, this is correct.

[skierdude494]

ok got that but i dont have the lines connected yet from the motor to the fuel lines on the car how do i check which is which

[Joe]

the line with the filter is the pressure linethe line without the filter is the return line.

[Darius]

To add to Kamin's comment, don't mix it up with the gas tank EVAP line that is near the two fuel lines. That line also runs to the fuel tank, but carries fuel vapors from the tank to the intake tract on the KA to be burnt for air pollution purposes and as I've found, to prevent your interior from smelling like gas.

[Joe]

To add to Kamin's comment, don't mix it up with the gas tank EVAP line that is near the two fuel lines. That line also runs to the fuel tank, but carries fuel vapors from the tank to the intake tract on the KA to be burnt for air pollution purposes and as I've found, to prevent your interior from smelling like gas.

that is 96+ only i think.

[DJButton]

Are the lines routed the same way on an RB20? I would imagine so, I have my feed line going thru the FPR then fuel rail then bottom line as the return line. I have a feeling mine are backwards.

[Joe]

they are the same on almost all engines (nissan or otherwise)

if the regulator is on the feed side, how would the injectors see pressure?

[DJButton]

Thanks Kamin,After looking at the lines again I ran into a wall to turn my brain back on, FPR before injectors... would simply be silly. Anyhow thanks to Carl confirming that before said wall slamming, I changed the lines, but the FPR may be shot, gee Carl thanks for warning me, she wont turn over now so back to figuring that out.

to O.P. sorry for using your thread but hey it's related.