I know what an injector is and how it works but my question is what is the difference between an high and low impedance injector?

 

Impedance is electrical resistance, which is measured in Ohms.

Low impedance injectors are around - 1.7 to 3.0 ohms
High impedance injectors are around - 10 to 16 ohms

Most manufacturers have used both types at one time or another,
but most later model cars use high impedance injectors.

You find out your injectors' impedance by putting a digital ohmmeter across the two electrical connections on the injector and see what it reads.

The main advantage of low impedance injectors is a shorter triggering time. When large injectors are fitted to high output engines, low impedance injectors will often give a better idle quality because of this. But you need to use external resistors so you don't burn up the ECU injector circuits.

The main advantage of high impedance injectors is the that less heat is generated in the circuit and usually no external resistors are used.

 

good stuff thanks guy