Injector Testing

When testing injectors it is important to understand how they are connected, controlled and ran.

They are controlled by the ECM on the GROUND SIDE.

SO there should be a constant battery voltage when the ignition switch is on the on position.

The rapid pulsing heard with a stethoscope is equivalent to the duration that the ECM allows a connection to the ground source.

The spike seen afterwards is the magnetic field induced when the current stops.

The final extra bump is the mechanical pintle valve closing within the injector.