I have a 1990 V12 with MM ignition and 16CU ECU. Does anyone know how many pulses per rev are output from the MM ignition unit? The service manual that I have only seems to refer to the later models. Do I get one injection pulse per rev? or one pulse per bank per rev? My car is not running at present so I can't measure it.

 

I do not know what the output of the Marelli ECU is. But I would guess the pulse output would be the same as the Lucas.

What are you trying to achieve?

 

I have a spare ECU that I'm playing with, I need to scale the RPM value from the test port. I thought I had read that there was one injector pulse per rev but I have also read that there are six pulses per rev from the MM unit, that would correspond to six pulses per RPM if my interpretation of the code is correct.
My understanding is that the earlier 16CU systems used the pulse to the distributor so six pulses per rpm.

 

The Engine Performance supplement says that injectors are fired every 3rd ignition pulse, but does not say how many ignition pulses per RPM.

Just found in the ROM that injectors are fired twice per engine cycle.

 

Thanks. I stuck a couple of gallons of petrol in it today and replaced the battery and it fired straight up so I will try and get a scope on it.