MR2 Turbo Center-Feed Fuel Rail: The Fuel Pressure Regulator

MR2 Center-Feed Fuel Rail Installation: The Fuel Pressure Regulator

Overview	Fuel Pump	Fuel Rail	Parts List

The Aeromotive 13109 adjustable fuel pressure regulator is the perfect complement to the mid feed fuel rail because it has two -6AN input ports to accept a feed from each end of the fuel rail. The most difficult part of the installation is finding a good location for the regulator. I installed it above the coolant overflow tank against the rear firewall, but that location was available because my TEC³ EMS allowed me to remove the resistor packs and the stock coil and igniter that usually reside in that area of the engine bay.

Apply Teflon tape to the threads of two -6AN to -6AN flare unions and screw them onto the two side input ports of the pressure regulator. Apply Teflon tape to the -6AN threads of the Earls 981662 -6AN to 1/8" NPT adapter and screw it onto the bottom fuel return port. Apply Teflon tape to threads of both the adapter on the fuel return port and the Earls 984004 1/8" NPT to 1/4" ID hose barb. Use the Earls 991001 1/8" NPT coupling to connect the hose barb to the fuel return port.

A critical part of the fuel system is an appropriate fuel pressure gauge needed to adjust the fuel pressure regulator to the appropriate base fuel pressure. The fuel pressure regulator comes with a 1/8" NPT port to connect most 0-100psi fuel pressure gauges. I used a NordSkog electric fuel gauge and sensor combination to generate a signal that my TEC³ EMS could datalog, but there are plenty of mechanical gauges that are much less expensive and will work well for adjusting base fuel pressure. Regardless of which gauge you choose, apply Teflon tape to the sensor threads and attach it to the fuel regulator.

Locate an appropriate location to place the fuel pressure regulator with all of its attendant paraphernalia (keeping in mind that the fuel lines and return hose will also have to be attached to it) and drill the appropriate holes to mount it using the bracket that came with it. Measure the distance of fuel hose required to run from the fuel return hose bard on the pressure regulator to the the fuel return pipe near the front firewall heat shields. Cut the appropriate length of hose and clamp it in place using the Econ-O-Fit hose ends. Measure the distance from the fuel ports at each end of the fuel rail to the ports on either side of the pressure regulator. Determine which combination of 90 degree and straight -6AN hose ends will best allow the fuel lines to run to their destinations without sharp turns or kinks and construct the appropriate -6AN fuel lines. Use Teflon tape on all adapter threads to form tight seals and avoid over tightening the connectors.

Double check all your work and reconnect the battery. Connect the +B and FP holes in the "Diagnosis" box with a heavy gauge wire or paper clip and turn the ignition key to "ON." You should hear and feel fuel coursing through the fuel lines. Check thoroughly to ensure that there are no fuel leaks in the system. If there are any leaks, shut down the system and fix it before proceeding. Once the fuel system is verified to be free of leaks, adjust the base fuel pressure of the system to the appropriate pressure. If using an EMS, 43 psi is the standard fuel pressure used to measure injector flow rates and that is probably the best place to start unless you have other requirements.

Cut an appropriate length of 4mm vacuum hose and connect the vacuum tube on the fuel rail to the vacuum nipple on the fuel pressure regulator. Torque the bolts to 14 ft-lbs. Bolt the bracket with the EGR vacuum modulator and VSV back on the manifold and connect the VSV engine harness connector and the hoses back to their respective locations. Reattach the evaporative and EGR lines to the top of the throttle body. Reattach the water lines and the air line to the ISC valve on the bottom of the throttle body. Reconnect the ISC and TPS connectors on the engine harness to their proper connectors. Bolt the throttle body back onto the intake manifold with the appropriate gasket between them. Place the throttle body stay in place and bolt it on. Torque the 12mm bolts to 14 ft-lbs. and the 10mm bolts on the valve cover to 10 ft-lbs. Bolt the throttle body inlet to the throttle body with the appropriate gasket between them and torque the bolts to 14 ft-lbs. Bolt the throttle cable bracket to the throttle body and torque the bolts to 14 ft-lbs. Reattach the throttle cable. Reattach the turbo hoses between the throttle body inlet and the intercooler and tighten the clamps appropriately.

The engine can be started after appropriate measures have been taken to control the larger fuel injectors. The fuel pressure gauge should indicate a pressure approximately 8 psi lower than the base fuel pressure during idle when the engine warms up.