This capture is from a 2006 VW TFSI, direct injection turbo charged engine. This is a differential coupling and you can see it resembles the common rail diesel injector pattern. The control unit contains capacitors that provide the high voltage used to operate the injectors, usually 2 capacitors for a 4 cylinder engine.
This waveform image shows the detail of a common, multipoint petrol injector, mounted in the inlet manifold. (Indirect injection or manifold injection). This was taken from a 2006 2.0 Mazda.
This next waveform set, show a sample taken from a direct injection petrol BMW (N43), which uses piezo injectors. The first image shows a full cycle of cylinder No.1. I have used a maths channel to show the actual injector opening signals, as the other voltage signals can be confusing. They are the ghost signals from the driver circuit in the ECU and completely normal. Unfortunately I was unable to get a current clamp in place to sample current. But, as you will see, I have managed to show what the current pattern would look like, from the ground side voltage drop.
This next image is a capture of the same type of petrol injector as above, only this one has a current sample also. It plainly illustrates how the current signal mimics the volt-drop shown in the ground voltage signal above.
This image was taken from a 2016 Direct injection petrol engine, fitted in a Vauxhall Astra. It’s a 1.4 litre turbo with Delphi engine management.
The injectors are of the solenoid type.
Mark Stammers Diagnostics 