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Street Class Unlimited Class
DOHC SOHC Ion Updated 1/05 For the most recent list of the fastest five cars click here. |
D.I.Y. Adjustable Fuel Pressure Regulatorby:TitanWhen turbo charging a Saturn car one of the first things to address is the fuel system. More fuel must be injected into the engine to prevent the engine from running lean. In order to deliver more fuel to the engine many people will replace their stock 19lb fuel injectors with higher flowing ones. This fixes the problem of supplying an inadequate amount of fuel to the engine but often creates another problem, too much fuel. The PCM is not able to compensate for the larger injectors creating an overly rich mixture, which causes poor gas mileage, erratic idle and decreased power output. Lowering the fuel pressure is one trick that can be employed to fool the computer into thinking that the injectors are smaller than they really are. Don't want to spend the money on an aftermarket fuel pressure regulator? Don't worry, your Saturn (up to 97) may already have a fuel pressure regulator that can be modified to adjust the fuel pressure. Here's how it's done… Locate the fuel pressure rail bolted to the intake manifold. Now, following the fuel rail toward the throttle body and locate a small circular object right before the return line exits from the fuel rail. This is the fuel pressure regulator (FPR). To reach the FPR you will have to remove the throttle cable, bracket and vacuum lines attached to the FPR. Once everything has been removed you will clearly see that the FPR is held in place by a metal clip. Remove the clip, using either a screw driver or needle nose pliers, pulling in a downward direction toward the engine. Once the clip is off the FPR can be easily removed. Be sure to mark the stock setting so that you can reset the pressure to stock setting before re-installing. CAUTION: There are two other parts, an o-ring and filter, that are held in place by the FPR and can easily be lost. Now that you have the FPR off of the car use a #10 safety torx
bit and gently begin turning the torx screw back and forth until
the screw becomes free. I recommend removing the FPR from the car
because it is easier to break the set screw free without runing
the FPR. Once the set screw is free re-install the FPR and attached
all of the brackets and hoses. Now attach a fuel pressure guage,
turn the key to run and check for leaks. If there are no leaks start
the car and observe the fuel pressure at idle, it should read about
43.5psi. Now to adjust the fuel pressure simply turn the screw clockwise
to increase fuel pressure and counter cloclwise to decrease fuel
pressure. Once you have the desired fuel pressure set it's a good
idea to place a small amount of lock tight on the screw to make
sure that it doesn't vibrate out. Also, take note that the fuel
pressure increases by about 5psi when the engine is above idle.
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