i've got an autometer fuel pressure gauge inline between the fmu and fpr to get a good reading. at idle its around 30psi. when i hook the vacuum line up to the fmu the gauge drops to 0....whats up with that? so i got the crx turbo'd now and i have that vacuum line blocked off and adjusted the top nut so i have around 38-40psi right now until i can figure this thing out. maybe it needs to be rebuilt? any advise would be appreciated if any. oh yeah, and i'm only runnin 4psi on some sorda mazdaspeed wg on a 2g t25 on my 87 crx si.

 

Sounds like you have a leak somewhere. If you plugged it up and it got vaccuum again then that would be my logical bet.

 

ok, sorry to bring back an old post but i didn't see the point in openin up a new one with the same question. so now i have the newer style cartech/begi 2025. i have it hooked up the same way as the older style. the stock fpr, t's off to the gauge, fmu, then return.......as it should be. it does the same thing tho....as soon as i hook up the vacuum line to the side port the gauge reads ZERO. i take it off and it reads pressure. but if i hook it up to the needle valve (which is supposed to have the check valve ventin to atmosphere) it will still read the psi but it'll go to zero as soon as i put the check valve on the side port. idk what the deal is........am i needing a restrictor on the vacuum line or something. hell, its just a 87 crx si....didn't think itd be this complicated.

 

take a picture of how you have your hoses run.

 

as per cartech install instructions....duh.....its installed on the return side.......
so from the stock fpr i have the t for the fuel psi gauge, then on the IN port of the fmu, out the fmu to the end of the return.........check valve on the needle valve ventin to atmosphere.....and supposed to have vac to the side port.....but my gauge drops to ZERO when vac is hooked up.........stumped....

 

I can't tell a whole lot by your pics. Just curious why are you hooking up a fuel pressure gauge there anyways? At idle (when you can actually be outside of the car and looking at the gauge) the pressure is gonna be stock fuel pressure. Have you tried hooking it up without the pressure gauge?

 

i don't see how a gauge would affect anything tho? this might fix the problem, but i'm gonna try and tap into that top bolt on the fuel filter....anyone know what size that is? i have my gauge in my lil center console so i can monitor the psi for tuning purposes.

 

since you're running an fmu why not just plug tune that bitch?