Thread: liquid filled fuel pressure guage

so, installed my guage between fpr and fuel pressue guage, right after 255 lph walbro fuel pump install. tested for and fixed a few leaks i found. tested a second time and had no leaks, but no jump, spike, flinch, nothing from the guage needle after multiple tries with key turn. took off the return line and fuel sprayed everywhere. do those guages need constant pressure for reading, warm up, or a specific orientation(vertical, horizontal, etc) to function properly? thanks

The gauge needs pressure to have a reading. It needs to be hooked up to the feed side, not return side. The feed comes from the filter. The return comes out of the pressure regulator. Post up a pic, sounds like you got it hooked up completely wrong.

sounds like i did fudge that up. i was looking at posted pics of other engine bays and to me it looked like guage was between fpr and fuel rail. which went with my understanding that the gauge was jus before the rail to make sure injectors were getting correct pressure. so i went fuel filter--> fpr--> guage-->fuel rail.

so change it to filter--> guage--> fpr--> rail?
thanks

The FPR is part of the rail. You can't attach anything between it. You only have 2 fuel lines. One from the filter is the feed (pressure), which attaches to the pressure gauge, then to the fuel rail (the side opposite the FPR), then from the FPR out to the return line. It's just a big loop. The fuel feeds to the FPR, then the FPR lets off the surge of fuel to a set pressure controlled by the FPR. It works similar to a BOV. The BOV lets off a surge of excess air over a certain PSI that it's set to when you let off throttle.

so filter, to guage, to rail, to fpr, then return to tank? y is fpr after rail? whats there to regulate on return line? not trying to be complicated, jus want to understand cuz that is clear as mud to me

pics help me so much lol

disregard.i found an article that broke it down pretty good, along with the pic.