Okay, I've been reading all these posts bout what lines go to what.. the diagram doesn't show up but here's my question. I disconnected the FMU to see if I got it on right. I got one line that leaks out fuel like crazy (I'm guessing it goes to the tank) and the other line does not. Now where does each line go to on the FMU? thanks


Alvin

96 RST

Star Stage I turbo kit /Starion I/C w/ 2" chrome piping / GReddy Type-S BOV / Missing Link / Custom APEXi- GReddy 2.5" exhaust / 55mm ARD TB/ Nology wires / APEXi EL mech boost gauge / Autometer A/F gauge / Southland Dual Friction clutch / B&M short shifter / Energy Suspension shifter bushings / 16" GSX Rims / Front/ Rear camberkits / Eibach Prokits / Tokico Blues/ Front Upper, Rear Lower strut bars / Rear GST sway bar/ GSX Dual Piston Calipers, X-drilled/ slotted rotors

bump
Alvin

96 RST

Star Stage I turbo kit /Starion I/C w/ 2" chrome piping / GReddy Type-S BOV / Missing Link / Custom APEXi- GReddy 2.5" exhaust / 55mm ARD TB/ Nology wires / APEXi EL mech boost gauge / Autometer A/F gauge / Southland Dual Friction clutch / B&M short shifter / Energy Suspension shifter bushings / 16" GSX Rims / Front/ Rear camberkits / Eibach Prokits / Tokico Blues/ Front Upper, Rear Lower strut bars / Rear GST sway bar/ GSX Dual Piston Calipers, X-drilled/ slotted rotors

Your question is somewhat confusing.

There should be an inlet and outlet. The inlet comes from the fuel rail and outlet which heads to the gas tank. I wouldn't even hazard a guess on which fuel line was which merely dependent on which had more fuel within it.

>The inlet comes from
>the fuel rail...

hmmm....i have my inlet connected to a vacuum source on the intake manifold and outlet going back to the gas tank....is there a difference because semperboost has a 95-96?

The top part is the vacuum line, middle I believe is inlet, and bottom is back to the tank. I think that is right, I havn't had a chance to install yet.

I think I've been running the FMU backwards for a couple months!!...Idiot! So the 96-99 Fuel system has a returnless fuel line, only one line leading to the rail. So the FMU taps into this line and restricts the flow to the rail, increasing pressure right? But doesn't this restrict the flow to the injectors? Can someone explain how this works please

Alvin

96 RST

Star Stage I turbo kit /Starion I/C w/ 2" chrome piping / GReddy Type-S BOV / Missing Link / Custom APEXi- GReddy 2.5" exhaust / 55mm ARD TB/ Nology wires / APEXi EL mech boost gauge / Autometer A/F gauge / Southland Dual Friction clutch / B&M short shifter / Energy Suspension shifter bushings / 16" GSX Rims / Front/ Rear camberkits / Eibach Prokits / Tokico Blues/ Front Upper, Rear Lower strut bars / Rear GST sway bar/ GSX Dual Piston Calipers, X-drilled/ slotted rotors

So the 96-99 Fuel system has a returnless
>fuel line, only one line leading to the rail. So the FMU
>taps into this line and restricts the flow to the rail,
>increasing pressure right?

Well, that's how STAR sort of has it done. But no, most HRC users have the SFMU tapping into the fuel line that LEAVES the fuel rail(the test port) and heads back to the fuel tank. By doing so, it causes pressure to BUILD in the fuel rail to whatever pressure is needed to make the car idle according to specification AND force the fuel injectors to become "bigger" by having more fuel pushed out due to the increased fuel pressures in the rail. Therefore, the fuel inlet line stays exactly the same.

But you're right about the 96-99 fuel systems having a RETURNLESS fuel system. That's why it's necessary to ADD a fuel return line to bleed the excess fuel after the pressure back to the fuel tank. That's how stock turbo cars work, and that's the optimal setup for your car.

Now, as I have repeatedly criticized before, the STAR system has you adding the standard FMU at the rear of a 96-99 fuel system where the stock FPR sits, and run a vacuum line to the back of the car thereby causing the same effect of increased fuel pressures throughout the entire fuel line and inlet. That seems a little weirder to me though, and I don't recommend it, especially given the length of vacuum line requried to message the FMU to increase fuel pressures during boost. Basically, it becomes the fragile "lifeline" of the car during boosted operations.


But doesn't this restrict the
>flow to the injectors?

Not if it's done according to the HRC method, by ADDING a fuel return line. Otherwise, you're right, it does RESTRICT flow TO the injectors, but at the same time, it INCREASES fuel pressure. But that's the concept of the newer innovative and more emissions friendly returnless fuel systems you see everywhere.

Now I'm thinking bout running some fuel line to put the FMU back into the engine bay. I better read up on that post above bout SS lines. I'm just gonna rin some hi-pressure fuel line if possible


Alvin

96 RST

Star Stage I turbo kit /Starion I/C w/ 2" chrome piping / GReddy Type-S BOV / Missing Link / Custom APEXi- GReddy 2.5" exhaust / 55mm ARD TB/ Nology wires / APEXi EL mech boost gauge / Autometer A/F gauge / Southland Dual Friction clutch / B&M short shifter / Energy Suspension shifter bushings / 16" GSX Rims / Front/ Rear camberkits / Eibach Prokits / Tokico Blues/ Front Upper, Rear Lower strut bars / Rear GST sway bar/ GSX Dual Piston Calipers, X-drilled/ slotted rotors

>Now, as I have repeatedly criticized before, the STAR system
>has you adding the standard FMU at the rear of a 96-99 fuel
>system where the stock FPR sits, and run a vacuum line to
>the back of the car thereby causing the same effect of
>increased fuel pressures throughout the entire fuel line and
>inlet. That seems a little weirder to me though, and I
>don't recommend it, especially given the length of vacuum
>line requried to message the FMU to increase fuel pressures
>during boost. Basically, it becomes the fragile "lifeline"
>of the car during boosted operations.

God bless the 95's (makes for some tidy vacuuming routing on 96up for fear of the above. I think I prayed for the vacuum line when I ran it in Dualgens OBDII. so far so good I guess).

Out of curiousity where does the Hahn kit return line dump into the gas tank on 96up models? Do you T or use the existing return line from where the factory rear regulator dumps or do you put a fitting somewhere else?

>Out of curiousity where does the Hahn kit return line dump
>into the gas tank on 96up models? Do you T or use the
>existing return line from where the factory rear regulator
>dumps or do you put a fitting somewhere else?

We run a new line from the test port, to FPR, then after removing the rear stock FPR, we use the existing return line as you correctly guessed. No tee'ing necessary.