my fp guage is now mounted to the test port in the fuel rail and it is stuck at idle fp (either 45 or 50 i'm spacing it right now)until i go under boost then it goes up. so i'm wondering if yours does the same thing. i don't really know how it should work but it seems to me that if i put my foot to the gas the pressure should start rising right? even when i'm laying into the throttle it doesnt move until i'm in boost. does this sound correct

Yeap.

Mine moves about 5psi under partial throttle because my stock regulator is still in place and fully functional. If you're using an SFMU with the stock regulator disabled, it won't move until you hit boost.

Either way, it's not something to worry about. You can't read 5psi on that damn gauge anyway :D

another fp gauge question...

will the pressure at that test port on the rail be the same pressure as the line that goes into the fuel rail?

it's the pressure in the rail that matters anyway. :wary

ok, i know this, but is the pressure of the line right before the rail the same as the pressure @ the test port?

i have my fp guages T-d off the line that feeds the rail, much like the way hahn does there fp gauge... is this just as accurate as have the sender hooked to the test port?

So what about when you go from idle vacuum to 0 boost? If the idle fuel pressure is around 44 psi, shouldn't the fuel pressure rise a little at 0 boost 0 vacuum and then rise according to boost? This all assuming the stock regulator is disabled and a vortech SFMU is being used.

-Jared
96 GS
Melbourne, FL

He's using a stock FPR on rail (unhooked vac line) and regular FMU. Because it is set up like this, you should see one number (50 psi?) from full vacuum to 0 boost. From 0 boost to 8 boost, expect the pressure to rise linearly.

Corbin

'95 ESI-T
HRC+FMIC+ETC...



Gimme fuel...Gimme fire...Gimme that which I desire

still wondering if it matters where you put the fp guage at... is it ok to have it in the line that feeds the rail, or is the pressure there going to be different than the pressure at the test port on the rail?

The pressure should be very close. Each bend or disruption in flow will cause a pressure loss, but the difference between in the rail and the rail input should be small. You may not even be able to see it on a standard gauge.


Corbin

'95 ESI-T
HRC+FMIC+ETC...



Gimme fuel...Gimme fire...Gimme that which I desire

cool, thats what i thought, just wanted to be sure. thanks again corbin :)