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Discussion Starter #1
I just had a Vortech S-Trim installed on my 99 GT. I am very pleased with the power that it makes, although, I seem to be having some problems.

When I first start and drive the car everything is fine. But after the car has been driven for 20 minutes or so, I notice the fuel pressure getting higher and higher. When the car sits and idles for a little while, I can actually hear the fuel pump whinning. As it whines the fuel pressure jumps "N'Sync" with the noise, and flucuates from 30psi to 70psi. It actually sounds like the pump is sucking air. Once this starts occuring it detonates REAL bad while under boost. And Feels like I've lost ALOT of power.

It is frustrating the hell out of me, and the detonation seems to be geeting worse. But once again...........after the car has sat overnight everything is fine. I can't figure this out. Any info or ideas would be greatly appreciated.

Here are a complete list of Blower/Fuel mods.

1999 Nustang GT 5 speed
Vortech V-1 S-Trim
FMS 42 LB injectors
90 mm Lightning Mass Air
255 In Tank Pump
Anderson Power Pipe
Diablo Chip

Dyno #'s at first

373 RWHP 361 RWTQ

it now feels more like 300-310 (Somethings not right)
 

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Discussion Starter #3
All Parts are Brand New.
 

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WEll I didnt see an fmu in there so that cant be the problem. The only way the fuel pressure is going up is if there is a restriction. So, your regulator could be failing at it gets hot. That is the only theory I can come up with--I suppose the pump itself may be doin something weird as it heats up too. If you can leave the car idle and go back with a rubber mallet or you hand and beat on the tank while it is doin it--you might be able to cause a change. If you do the pump is probably to blame. I would definitely look at something failing due to heat since it doesnt do it while cold. I highly recommend an adjustable fpr so if you dont have one just replace the stocker. And dont hammer down while lean!!!
 

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Discussion Starter #5
The car is a 99 GT. The car doesn't have an FMU.


We have now switched the pumps out twice. Now the car idles fine, but Fuel Pressure cuts out under boost. I'm getting very frustrated at this point.
 

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do you have a chip or something with no fmu? Generally if you are losing fuel pressure it is because the engine is consuming more fuel than the pump or lines can support. Make sure you dont have a kinked line restricting fuel volume as that will result in lost pressure when under boost.
 
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