After searching for info on hooking up the Vortech FMU, I understand it I THINK.
So on the top of the FMU I hook up a vacuum hose that goes to the intake manifold. Then on the bottom 2 fittings, one is the return line from stock fpr & the other is a return line to the tank.. but which one is which? Which one is the one on the very bottom of the FMU for?
The test port?? The FMU is placed inline with the fuel return line..the FMU restricts the flow of the return line (via diaphragms, piston) based on the boost level and cal. disk. The more it restricts the flow the more fuel must get dumped to the injectors. Correct me if I am wrong please but this is how my 96 works
Alvin
96 RST
http://www.kaptainmyke.com/tir/gallery/SemperBoost Star Stage I turbo kit /Starion I/C w/ 2" chrome piping / GReddy Type-S BOV / Missing Link / Custom APEXi- GReddy 2.5" exhaust / Nology wires / Dual Gaugepod pillar mount / 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 Upper/Lower strut bars / Rear GST sway bar X-drilled rotors / Axxis pads / Stock GS/GST sideskirts /Color-matched center taillight/ door handles/ sideviews Cleared Headlight turns/PIAA bulbs
The test port (on the fuel rail that has the schraeder fitting inside it) with 96+ 420a's IS the start of the fuel return line. Both of the above explanations are totally correct.
I'm not sure if Alvin has one of those fuel return lined 96's, but it's a possibility. Otherwise, we all use the fuel test port on the fuel rails for the start of the fuel rail. Mating a fuel line to it that eventually mates up to the side inlet of the SFMU and then eventually out of the bottom outlet and then leading into the fuel tank comprises the complete return side of the turbo fuel system.
_____________________________________ Jason ESi-T
04' BMW 325Ci 91' Nissan 240SX 98' Eagle Talon ESi (sold)
#29646, "RE: fuel system" In response to Reply # 3
I had to mount the FMU right near the fuel tank because of the whacky fuel sysem..I think only 95 and early 96s have this. The other options to get the FMU out of this dangerous spot was to 1) get a boost-a-pump 2) get a different fuel rail. My FMU hasn't sufferend any damage but it is getting repaired cuz I guess when one of the mechs took it apart to tighten a fitting he forgot to put the piston back in when regulates the fuel..doh! So I've been running low boost for about 6 months not knowing I wasn't getting enough fuel...doh!
ALvin
96 RST
http://www.kaptainmyke.com/tir/gallery/SemperBoost Star Stage I turbo kit /Starion I/C w/ 2" chrome piping / GReddy Type-S BOV / Missing Link / Custom APEXi- GReddy 2.5" exhaust / Nology wires / Dual Gaugepod pillar mount / 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 Upper/Lower strut bars / Rear GST sway bar X-drilled rotors / Axxis pads / Stock GS/GST sideskirts /Color-matched center taillight/ door handles/ sideviews Cleared Headlight turns/PIAA bulbs
#29647, "RE: fuel system" In response to Reply # 4
>I had to mount the FMU right near the fuel tank because of >the whacky fuel sysem..I think only 95 and early 96s have >this.
Actually, you have another option. Most of all 96+'s in fact do not have a fuel return line and we are required to install a line under the car to the fuel tank so that we can install the FMU or FPR by the fuel rail instead.
It's my own opinion that installing a FPR or FMU back by the fuel tank is pretty "WHACK" for the same reasons why you had your problems with leanness. I suggest adding an aluminum fuel line from the fuel rail to the fuel tank and having the FMU in the engine bay between that line and the rail. You can use the same rail, just use the test port on the rail as the outlet to the FMU.
_____________________________________ Jason ESi-T
04' BMW 325Ci 91' Nissan 240SX 98' Eagle Talon ESi (sold)
#29648, "RE: So what you are saying is.." In response to Reply # 5
Make a split in the fuel return line then run a line from that to the FMU, place the FMU in the engine bay and connect a line from the test post to the FMU???
ALvin
96 RST
http://www.kaptainmyke.com/tir/gallery/SemperBoost Star Stage I turbo kit /Starion I/C w/ 2" chrome piping / GReddy Type-S BOV / Missing Link / Custom APEXi- GReddy 2.5" exhaust / Nology wires / Dual Gaugepod pillar mount / 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 Upper/Lower strut bars / Rear GST sway bar X-drilled rotors / Axxis pads / Stock GS/GST sideskirts /Color-matched center taillight/ door handles/ sideviews Cleared Headlight turns/PIAA bulbs
#29649, "RE: So what you are saying is.." In response to Reply # 6
>Make a split in the fuel return line then run a line from >that to the FMU, place the FMU in the engine bay and connect >a line from the test post to the FMU???
If you have a fuel return line, no split is necessary. Merely, place the FMU inline with the stock fuel return line in the engine bay. Then you can send the boost reference vacuum line to the FMU right in the engine bay, and have much less risk of going lean with a faulty vacuum line.
The usage of the test port is only for those of us (96+'s with alte fuel system) who do not have a stock fuel return line.
_____________________________________ Jason ESi-T
04' BMW 325Ci 91' Nissan 240SX 98' Eagle Talon ESi (sold)