Carb to Electronic Fuel Injection | Performance Cars Building Brisbane

Now when I talk EFI, I am talking about full engine management. Let’s first touch on a little history.

Before fuel injection we had carbie and points. Firstly the points or Kettering system was replaced with electronic ignition.

This gave us a better spark to ignite the mixture but still had mechanical and vacuum timing advance.

Next was throttle body or single point fuel injection which replaced the carbie with a fuel injector squirting fuel into a standard wet manifold.

On wet and dry manifolds, a wet manifold is one that contains a mix of fuel and air while a dry manifold only contains air. Carbie and throttle body type injectors are considered to be wet while port and direct injection is dry.

I know mechanical fuel injection also exists, for the purpose of this discussion lets ignore it.

Now that we had a computer a few sensors for the throttle body injection it only was logical to add a little more computer power and have full engine management which controlled fuel and spark. Considering the added benefits of complete engine management this is the type of conversation we will discuss.

We have a few options to convert carbie to fuel injection. If the manufacturer had an option for engine management we can use the components from that. Parts like inlet manifold (which will have throttle body, fuel rail, injectors and TPS), engine sensors for cam, crank and coolant. I am not going to list them all we will cover them more when we choose an ECU to run it all. Ignition system parts will be used also.
We can use our current manifold and remove the carbie and fit a throttle body injection system like, Fast or MSD. When using this you will also need a way to remove the mechanical and vacuum advance if your engine has a distributor.
We also have many aftermarket options available manifold wise for popular performance engines.

Race Auto Maintenance

Fuel injection requires a high pressure electric fuel pump and regulator for fuel supply. These pumps are generally a push type pump. Push pumps are good at pushing the fuel at high pressure to the engine. These pumps do not draw or suck well because of this they must be situated near the fuel tank.
The pumps are well suited to being fitted inside a fuel tank or gravity feed external to the tank. In some cases it may be necessary to use a small internal pump to feed a surge tank and the main pump gravity feed from the surge. The pump will have to be wired in using a relay and fuse. Your ECU will be able to control the fuel pump operation.

Fuel-injection

Ignition system is where you can maintain that stock look or change it all. If you want the look of the distributor you can lock the advance in yours or use one of the many aftermarket disruptors built for engine management. Don't like the look of a distributor, with all that computer power why not go to a coil on plug set up. One coil per each cylinder for maximum bang.

Vehicle Engineering

The brains of it all is the ECU. With a manufacturers optional EFI engine you may choose to run the original ECU. This is a perfectly sound option. With a number of factory ECUs able to be flash tuned you have the ability to make changes and even add forced induction. Using factory sensors will make the whole job easier.
Since we are into modifying cars, this is where we get to have some fun choosing an aftermarket ecu. Whether you use a Haltech, Adaptroinc or any one of the many good aftermarket ECU available your options open right up. Knock control, wide band O2, flex fuel, boost control are all there.

Wiring it together can mean cutting and splicing a factory harness or a complete custom harness. All those sensors will need to be connected to the Ecu in the correct place along with outputs and controls. Other power supplies like ignition feed, power the whole lot. Once all wired up time to test it all works correctly.
Then it is Dyno Tune time. This is when we set up of the maps for fuel and ignition.
Along the way many other little things will almost always pop up. Acceleration cable length, radiator hoses ETC. Those are all the little challenges we face when modifying cars.

Carb to EFI

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