cushti

iTrader: (7)

Just done parallel fuel rail & fitted SX fpr. Turned ignition on, pump primes itself & fpr goes up to only 1 bar then drops back to zero (I've wound it out quite a few turns so 6 threads are now showing but the pressure doesn't seem to be getting any higher). I turned it over & it seems to run fine at idle but fpr still reading only 1 bar constant so I don't want to run it too long or press the throttle as it should be 2.6 bar. Everything ran perfect before conversion & no leaks I can see.

- having the vac hose connected or disconnected to the fpr from the inlet manifold makes no difference to the pressure reading.
- no matter where I turn the thread on the SX fpr the reading is always around 1 bar on the pressure gauge (thread wound virtually right in it reads 0.8 bar & wound out about 10 threads it reads 1.0 bar)
- I know the gauge is working because I clamped the bit of return hose pipe after the gauge, turned ignition on & it shot up to 4+ bar
- fuel pump is a Walbro one & done less than 500 miles
- spent last 4 hours going around all the vac pipes, hoses & manifold itself looking for cracks or splits but everything looks sound. I also put new gaskets on manifold & ICV

Any kind person have any ideas: such as the fpr is knackered?!

cushti

iTrader: (7)

......I just got the grinder out & cut the old stock fpr off the old fuel rail & fitted this in-line between the sx fpr & the pressure gauge. Guess what it reads now - yep, still 1 bar?

Any ideas anyone, please???

apalmer

iTrader: (8)

Just thinking.. have you connected your FPR on the fuel tank return line or the feed? Also did you ptfe all your connections? You'd would have noticed if you hadn't i'm sure!

@

chrisdicko

iTrader: (21)

Not sure if I'm of any help, but mine was fitted today (HKS though), and I used this Carl Davey, specialist Subaru Impreza parts supply and just connected the two fuel lines, and a vac pipe.
Have you connected the fuel lines the right was round?

apalmer

iTrader: (8)

Just had another thought.... bing... i have a sard fpr and with the gauge kit i had an inline rail adapter so i could measure rail pressure (not just gauge) really they should be the same but at least you could tell if the gauge was faulty or not. Another thing could be your connections to the adapter, have you connected the pipes the right way... ie, rail and return into correct ports?

@

cushti

iTrader: (7)

Hi chaps.

The FPR is definately on the return, not the feed. I bought some 2nd hand rails (with -6 jic ends) off Carl Davey so no need for a fpr adaptor. I have it set up as follows:

1. The feed hose (that comes out of the fuel filter) goes to a t-piece at the front that supplies the fronts of each rail
2. The two hoses out the rear of the rails then go into each side of the SX
3. The bottom return port of the SX goes off to the in-line pressure gauge then back to the tank

Ah, now I've had a brainstorm but it sounds too easy. Should the pressure gauge be BEFORE the fpr then (i.e: rail-gauge-fpr-tank instead of how I have it set up which is rail-fpr-gauge-tank)?

(it would make sense as the pressure needs to be read before the fpr as it wants to maintain the pressure in the rails, not afterwards when it goes back to the tank)

Slowboy Racing

FPR gauge needs to be on the pressure side of the feed. So you should have the fuel feed from the tank > fuel filter > fuel rails (OE reg removed) > FPR gauge > FPR > return to tank.

apalmer

iTrader: (8)

Yep defo measure fuel pressure before the FPR, or from FPR not after it.