MoTeC Global Forum

Hello all

I am very new to the motec world. We are working on a 12 Ford Mustang with the factory ECU and an SDL dash logger. The system was set up to monitor many aspects of the suspension and more, but I am looking for monitoring the fuel used in order to calculate when we need pit stops for endurance racing. The car does have an aftermarket fuel cell and a sending unit, but it seems less than the most accurate way to go.

It seems with modern cars they monitor the fuel usage to calculate MPG, miles to empty and the like so I imagine the ECU is looking at consumption. I would imagine you can pull this off the OBDII port information. All of this is WAY over my head and I'm trying to figure this out. Any dumbed down advise would be greatly appreciated. I'm going through videos and the manual but not getting anywhere.

Thank you so much.

Jake

It is possible that the factory ECU will transmit Fuel Usage on the OBD port but not guaranteed. Unfortunately the SDL does not have built in OBD-II functionality so you wouldn't be able to read it directly.

The only possible way to be to reverse engineer the CAN bus and workout where fuel usage is being sent (if it is at all) and then create a custom CAN template that reads the data in. Unfortunately that is possibly a very difficult task.

You best way forward is to probably just use the sender unit, it may not be overly accurate but at least it is something.

I helped an endurance team (using a factory ECU with no fuel usage sent over CAN) calculate an accurate fuel used by monitoring an injector pulse width. We spliced into the wiring going to an injector and were able to connect this to a digital input. We calibrated the input as pulse width (needed something tricky for when we stopped). I think we used the pulse width as input to a table of fuel volume -- then we used that as the raw input to the Fuel Calculation.

We just changed the scaling on the Fuel Used calculation to match actual fuel usage, and it was pretty good. Certainly helped them.

Using this idea, if you could get injector pulse width, or even injector duty cycle from the CAN bus, you could convert this into a value useful for the Fuel Used calculation.

Wow both amazing responses that are way above my head. Either of you aware of anyone in the Philadelphia, PA area that may be up to the task? Because clearly I'm in over my head...

Thanks.

Jake