Can anyone help me out? I have a 99 si on a vortech charger. My fuel pressure is rediculous, at idle it sits around 21psi when Im wot its constantly rising...up over 100psi and off my gauge Wil the rising rate Vortech FMU keep the pressure rising? Or should it taper off and hold steady somewhere?

 

Yeah, it is the FMU...
It is a rising rate correct? And you have the vortech supercharger, that does not hit full boost until redline correct? So as you are approaching redline, the boost is increasing linearly, and since it is a rising rate FMU, I would think it will keep raising the fuel pressure as long as the boost pressure is rising...

The more boost, the more the FMU cuts off fuel return to your tank, making your fuel pressure rise enough to increase the amount of fuel entering the motor under boost, keeping your motor from breaking (detonating)...

Sorry to hear that, I would have to say ditch the FMU and get some 450cc injectors and some good tuning...
Basically the FMU is a CHEAP ass way to increase the amount of fuel to the engine, and it does not work very well... Hope u don't blow any of your fuel lines...

Good luck.