It would be easier to build out the Quarinjection project if I just sourced a bunch of parts designed for the DIY-EFI/Hotrod market. However, one of the challenges of this project was to design robustly on as thin a budget as possible. I sourced off the shelf items designed for high volume production cars which will make the engineering/integration more challenging, but lower the overall cost by allowing me to source from any suitable vehicle and aftermarket manufacturers.

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What is needed to run an engine with Electronic Fuel Injection? It’s no different than the 60’s technology that the engine runs on now. You need the proper ratio of fuel and air and a well timed spark.

Existing Engine

Fuel Delivery – Pump: The little V4 has a physical diaphragm fuel pump driven by an eccentric lobe on the camshaft. This sucks gas from from the fuel tank and delivers a few PSI of pressurized fuel to the carburetor.

Fuel Delivery – Carburetor: The V4 has a Solex 28/32 PDSIT-4 carburetor. This regulates the amount of fuel by taking into account the temperature and load on the engine as well as the movement of the accelerator pedal. The carb functions as both ‘sensors’ and the ‘control mechanism’. It is an analog calculator.

Spark Delivery – Generation: The spark is supplied by the ignition coil. It’s similar to transformer (with a trick) to go from 12 volts to 40,000-50,000 volts. The trick is that when you remove the supply voltage from the coil, the magnetic field collapses and generates the high voltage spark.

Spark Delivery – Timing: The V4 has a Bosch distributor which regulates timing of spark based on engine RPM and engine load. It is another analog calculator.

Electronic Fuel Injection

To replace the functions of the existing engine with modern EFI, these are the elements needed:

• Fuel Delivery
  • Fuel Pump
  • Fuel Lines
  • Injectors
• Spark Delivery
  • Ignition
• Sensors for engine load, timing and temperature
  • Throttle Position Sensor (TPS)
  • Manifold Pressure (MAP)
  • Crankshaft Position Sensor
  • Camshaft Position Sensor
  • Inlet Air Temperature (IAT)
  • Coolant Temperature (CLT)
• An ECU computer to coordinate the sensors and delivery
  • Computer Selection