Ficht DI Injector Operation

[ajv00303]

I want to better understand the operation of the Ficht DI Injector.
According to the schematic in the Manual there are 2 wires going to each injector, looks like a constant 40V and the other wire goes to the EMM.
I assume this 2nd wire (coming from the EMM) gives the injector the command to fire, is this a gnd connection?
So, if I had a spare injector and wanted to "experiment", I would basically connect 40V across the 2 pins on the injector and switch it on/off to simulate the operation when on the engine.

[SEAHORSE]

The injectors only "operate" in thousandths of a second.
Using 40 volts triggered by hand would probably burn out the internal coil windings very quickly. When running, the injectors are cooled by the circulating gasoline in the system, which in turn is kept cool by the water-cooled vapor separator tank.

https://www.crowleymarine.com/d/supp...rect-injection

[ajv00303]

So my basic description is correct, the wires coming from thr EMM get pulled down to fire the injector I understand the PW and Duty Cycle of the pulses will change with fuel demand and fuel is needed to cool the injector.

[SEAHORSE]

The EMM only completes the ground circuit to fire the injectors, it does not "send" a positive pulse to them. A lot of people get confused by that.

[ajv00303]

The EMM only completes the ground circuit to fire the injectors, it does not "send" a positive pulse to them. A lot of people get confused by that.

Understood, that's why I stated constant +40v.
How much current does 1 injector draw? I assume <10A as there is a 10A fuse feeding 2 injectors on the PDP.

Another question: If there is a fuel supply to the input of the injector and it's not energized, does the fuel bypass the injector and come out the return port?

[CCGambler206]

So do etec fire the same way just 55v?

[SEAHORSE]

Yes and no.

Yes, the FICHT and E-TECs are activated by completing the ground circuit. No, the FICHTs have a return spring that returns the plunger home after firing - the E-TEC uses a reverse electrical pulse to stop the plunger and another pulse to return it to home, ready for the next activation.

[ajv00303]

@SEAHORSE

Can you provide the Pulse Width and Period to be used to test an injector?
I am trying to come up with a set-up to operate a Ficht Injector.
I plan on switching On/Off a 40V Power Supply. I understand the injector needs to be cooled, etc.1st need the waveform.......
I am NOT testing an injector from 1 of my engines, going to try to source one from an engine being parted-out.

This is kind of a lab experiment.....

[SEAHORSE]

Those are engineering specs and not published and not used by service personnel.

Years back there was a cut-a-way FICHT injector that was powered by a 9 volt battery and a doorbell button.

[ajv00303]

I have a set-up underway with a pulse generator driving a relay switching a power supply on/off.
I am also trying to source a Ficht Injector for eval/learning purposes.