using VEMS as just a wideband lambda

[miniminor63]

Hi

I have the VEMS ECU installed in the car, but the car its in will just sport a "regular" short stroke NA carbed distributor driven engine this year. I have done some research and it seems that the VEMS needs a crank signal to turn on the wideband sensor.

I would just like to put it in the exhaust, to check the AFR, while dialing in the carbs. The engine does not have a trigger wheel, and I will not install one as the engine is in the car.

Are there any workarounds?

[rob@vems.co.uk]

You can force the wideband to start using the terminal command:

Manmde02bye

As this is what we use to start the system when calibrating the sensor.

[miniminor63]

ah, of course. So this means that I could just use the terminal to look at the values? Or could I open megatune and look at it there then?

[rob@vems.co.uk]

If you opened terminal, banged that command in, closed it an the opened MegaTune it would work.
But if it was me doing this, I'd use the VEMS as a very simple ignition controller too:
Use the points as the primary trigger.
Have a fixed ingition table as the advance/retard is handled by the distributor.
Use a single IGBT channel to fire the coil, the firing order is taken care of by the distributor.

This will then give you some context to your fuelling data with at least RPM, but also manifold pressure, and air and coolant temps if you connect the sensors.

It would be fairly straight forward to get the first part working, and the next steps would be incremental.
You may even end up wanting to lock the distributor and try your own ignition curves - copying a known good curve from David Vizard's work would be case of locking the dizzy and banging the numbers in then tuning...