Electronic Fuel Injection - EFI In An Afternoon

Meanwhile, up top, the carburetor was removed and the FAST throttle body bolted in place with a fresh gasket between it and the intake manifold. The throttle return spring and existing throttle linkage is connected to the new throttle body. The FAST throttle body is a well-designed piece that includes four injectors, the throttle position switch, air temperature sensor, MAP sensor (manifold absolute pressure), and an idle motor, all in one very tidy package that is similar in size to the four-barrel carburetor you just removed.

Next the coolant is drained from the motor and the coolant temperature sensor is threaded into a coolant port on the intake manifold or other suitable location. Meanwhile the techs down under are plumbing in the feed and return lines for fuel. We must admit things were made easier for them here because our '52 already had a port in the tank for the return line. There are any number of ways to achieve this and FAST offers complete kits for fuel supply and return with the EZ-EFI fuel pump kit. If you are dealing with a vintage fuel tank the good people at Tanks Inc. can often supply the needed pieces for either in-tank fuel pumps, external fuel pumps, regulators, and return options. This fuel injection system required 43 psi of fuel to properly feed the injectors so engine-mounted pumps will not get it done, nor will wimpy neoprene fuel lines, and a return line is a must.

The high-pressure fuel lines were routed forward to the engine bay and the connections were made to the throttle body. The FAST fuel pressure regulator will keep pressure down to 43 pounds. Wiring was routed from the fuse panel to the FAST electric fuel pump using the EZ-EFI fuel pump relay harness. This completed our fuel delivery and return line work. You can also wire the fuel pump in directly from the fuel pump relay on your main wiring system if it is so equipped, but either way a relay will be needed to handle the load.

Next the ECU is located and mounted. This unit is water tight so it can be mounted either under the hood or inside the car. When mounting the ECU, keep the cable plug pointing down to prevent any moisture from running into the plug. Also be certain to keep the ECU as far as possible from electrically "noisy" components, such as ignition boxes, coils, and distributors as these components can cause problems with the ECU.

The best location for the ECU seems to be on side of the firewall, engine side, or interior in a location where you can see the face of the unit and the LED trouble light. Remember you will be routing a communication cable for the handheld interface so keeping the ECU close to the passenger components will make routing that temporary communication cable much easier. Finally, be certain the supplied cable will reach the ECU prior to drilling any mounting holes. Our unit found a home on the passenger inner fender panel.

Before the wiring harness is plugged into the ECU all the other connections are made to the various sensors and a constant, clean 12V power source is required. It is recommended that both the positive and negative wire be connected directly to the battery. This eliminates the potential low-voltage problems that can raise havoc with electrical components. Choose the options desired during the wiring process as the ECU can handle an idle increase when the A/C is turned on, electric fan controls, and fuel pump control. Wire in the accessories you want the ECU to control. This may sound a bit complicated but it is really very straight forward with a great direction booklet and clearly labeled wires. Next is a 12V power source that is hot in both the crank and the on/run position. This is connected to the 12V switched wire in the harness, once again, simple enough.