Negative Pulse Width

[Sailor]

Hello!

We have a problem with the injector signal of a M800. The values "Fuel Base Pulse Width" and "Fuel Actual Pulse Width" are very instable and sometimes get negative values. In the test outputs menu it works fine. But if we tow / start the engine on the test bench the problem occurs (no fireing). Additionally we dont get the duty cycle >50 % (in test mode 100 %). If we set values in the fuel main table too high (>50 % DutyC) it goes down to 0.
Compensations are all turned off.

Any Ideas?

Best regards from germany

[OmarK]

In the diagnostics window in ECU Manager are you getting any errors?

[Sailor]

Yes we get errors.

Error Inj 1 Combined - open
Error Inj 2 Combined - open
Error Inj 3 Combined - open

as permanent error and

Error Inj Max Duty sometimes as non permanent.

I have to say, that we have a 3 cyl engine, but just use one injector signal (injector 1). We convert the injector signal to analog (0-10V) to control a valve. To get a load like a injector we put a 1k ohms resistor on the injector signal to get the voltage to 0.

[MarkMc]

Hello,
I do not really understand what you are doing so you may need to send me your ECU configuration.

How have you set up your injector current in the ECU? The ECUs diagnostics for the injectors are based around how an automotive injector works. Automotive injectors are usually 0.5-5 ohms resistance for peak and hold injectors and 8.5-16 ohms for saturated drive injectors. If you have 1K ohm resistor on the injector outputs the ECU will see very little current on the output and give a Open Circuit error.

What crank and cam triggers do you have? Does the ECU become sychronized when the engine is cranked?

[Sailor]

Hello,

The problem has been solved already. We now put a 100 ohms resistance between, to get the signal stable. The error occurs, but does not disrupt. The Injector Current is set to 0. Problem was that we don't use injectors. We use the signal of the injectors to drive a natural gas valve. The ECU becomes syncronised.

Thanks for your response anyway.

Best regards