When you think of hot rodding, old carburetors, and high horsepower you don’t necessarily think of great gas mileage or, for that matter, easy starting on those cold mornings. Now, when you think of aftermarket fuel injection most of us picture complicated wiring diagrams and countless hours of programming with a laptop. Well, with Fuel Air Spark Technology’s (FAST) EZ-EFI fuel injection kit they took the guesswork out of the otherwise electrical engineer’s job and put it into a complete plug-and-play package. The kit comes complete with everything you need to convert your motor from carburetion to fuel injection in a few hours, depending on your skill level. The only thing the kit does not include is a way to hook up the fuel return line to your gas tank, but we’ll show you a few options on how to do that.
So why would you want to spend the extra coin to remove your carb when it works just fine? Well, for starters let’s look at starting and driveability. Have you ever tried to start your truck on a cold morning and it just seemed to not want to? Or worse yet, have you driven to a significantly higher or lower elevation and now your carb jetting is too lean or rich causing poor driveability? So, how does the FAST EZ-EFI fix this?
Well, there are sensors that fine-tune the vehicle’s fuel delivery to enrich or lean out the fuel mixture ever so slightly. The manifold absolute pressure (MAP) sensor’s main job is to detect and measure the engine’s load. The throttle position sensor (TPS) tells the ECU when the throttle is opened or closed and also takes the place of a carburetor’s accelerator pump. The intake air temp (IAT) sensor helps the ECU determine the air density and helps to adjust the amount of fuel that is given to the motor. If the air density becomes less dense then the ECU will decrease the amount of fuel, otherwise the engine would run rich and eat up gas. The O2 sensor’s job is to help fine-tune the fuel trim by measuring the amount of oxygen exiting the exhaust. If the O2 sensor reads a lean condition (15:1 or greater air/fuel ratio) then it can add a slightly longer pulse width to the injector to add a small amount of fuel to richen the mixture up. A rich condition (12:1 or less) can be fixed too, the O2 sensor will read the lack of oxygen in the exhaust and tell the ECU to decrease the amount of fuel by shortening the fuel injector’s pulse width. The rpm signal is picked up off your coil, aftermarket ignition box, etc., and helps the ECU determine the amount of fuel by calculating all the sensors’ data together, extremely fast.
So, why should I care about fuel control when my carbureted motor is running just fine? Well, without getting into a heated discussion about carbs versus EFI, let me ask you this: Do you know what fuel mixture your vehicle is running? Without an O2 sensor in the exhaust, or dyno time, you could be running your motor really rich, or worse, dangerously lean. Chances are that your carbed motor is running rich. While a little rich is not all a bad thing, too much fuel in the mixture can cause pre-detonation, poor mileage, fuel in the oil, black smoke, bad smells, carbon deposits, fouled plugs, and fuel-washing the cylinder walls, causing lubrication problems. Although the previous examples are the extremes of running an engine way too rich, the majority of us are just looking for a few more miles per gallon.
Since I already had my 383...
Since I already had my 383 on the dyno at Westech Performance in Mira Loma, CA, swapping the carb for fuel injection would allow us to measure and compare the dyno numbers back-to-back. Installing the EZ-EFI throttle body is as easy as removing your old carb and bolting down the new throttle body. The intake manifold needs to be a 4150-style to match the bolt pattern on the EZ-EFI throttle body.
After we bolted on the throttle...
After we bolted on the throttle body, Ernie simply screwed on the throttle cable. Ernie then positioned the cable so that there was a little bit of slack, and not pulling the throttle body’s butterfly open.
Included with the EZ-EFI kit...
Included with the EZ-EFI kit is a coolant temp sensor that needs to be installed, typically in the intake manifold. This helps the ECU determine how much fuel to add or remove, depending on engine temp.
The kit’s O2 sensor bung needs...
The kit’s O2 sensor bung needs to be welded in, and make sure you don’t leave any gaps for air to sneak into the exhaust system. Make sure that you are at least 20 inches away from the head, otherwise the O2 sensor may suffer damage. It’s also a good idea at this time to check all your exhaust gaskets for leaks because it could cause the O2 sensor to read a false lean condition, and add unneeded fuel.
Ernie pulled the simple wiring...
Ernie pulled the simple wiring harness out and gathered the wires that needed to be hooked up to the battery and the ignition12V power supply. Red wire goes to battery positive, Black to ground, and Pink to Ignition 12V.
You may or may not need to...
You may or may not need to use the rpm module, depending on your ignition system, but FAST includes it for your convenience. The provided module is used for a distributor and coil-type setup but you can use an HEI or MSD ignition-style box in place of the rpm module. Make sure you read the instructions when you get ready to install your rpm signal because there are several ways to wire the signal. You could cause damage to your ECU if you don’t wire the rpm signal correctly.
The ECU can be mounted inside...
The ECU can be mounted inside or outside the engine bay but FAST recommends you keep it away from direct heat sources, such as next to the headers. I will most likely mount my ECU on one of the inner fenderwells or the firewall.
Route the wiring harness so...
Route the wiring harness so that the injector wires are in order. The throttle body driver-side rear is the #3 injector and just to its left is the #4 injector. The driver-side front is the #1 injector and the #2 injector is the passenger-side front. Once all the injectors are plugged in the rest of the wiring harness can be plugged in with ease.
Since we were on the dyno...
Since we were on the dyno at Westech, the fuel system was already plumbed, but you will need to mount the fuel pressure regulator where it makes sense on your firewall. After the fuel lines are plumbed you’ll need to check for leaks and set the fuel pressure regulator to 43 psi. This baseline fuel pressure setting will work for motors with outputs of up to 550 hp.