Dash and ECU questions

An almost generic question about the way the dash interacts with the ECU

For instance does the average fuel (instant) consumption data come from the ECU or the dash or a combo of both?

The fuel gauge is (from what I have seen) intelligent that depending how you ride it will adjust to the consumption so that it will rise and fall.

Can the dash or does the dash interact with the ECU to affect fuel consumption or is this solely the ECU and the map within?

Apologies for being a numpty but I am curious and don't really know.

Fuel consumption data comes from the ECU.

The fuel level sensor is just a thermistor, and AFAIK the dash only displays the level determined by the voltage across the sensor.

There's no interaction between dash and ECU to affect fuel consumption. That's based solely on the ECU's calculated injector pulse width derived from the map + sensors + throttle.

Mark do you think that the ECU may 'remember' the last 'few' miles revs (injector ms delivered per hour) and use that to predict an mpg?

Mine used to predict very thirsty behaviour until i had done about 35 miles (no idea why), then it went to proper mpg but thirstier if i was above 5.5k - which implied an "intelligent" readout

No, there's no 'remembering'.

There's 'instantaneous' (ahem..) fuel consumption calculation based on injector pulse widths, injector flow rates, acceleration enrichment correction, fuel consumption scale factor, blah, blah, more correction factors and scale factors than you can poke a stick at..with the data sent to the dash over the CAN bus with all the other pertinent stuff like RPM, speed...which the dash then crunches and displays, slightly delayed...

Higher fuel consumption in those first 35 miles or whatever is probably also related to the engine temperature reading. As we know the 8V is a cold blooded beast at the best of times and takes an age to get up to full operating temperature. It’ll also be considerably thirstier in cooler conditions than in the height of summer.

The 2 valvers are, if anything, even worse! Even though they have an oil cooler thermostat the engine temperature sensor location and mount means that they chronically under-read and the cooler the weather the worse it gets!

Pete Roper wrote:

Higher fuel consumption in those first 35 miles or whatever is probably also related to the engine temperature reading.

Isn't that what I said?

I was just reinforcing the temperature sensor input being probably the most critical. My shitboxes get 30km more distance to a tank to ‘Light on’ in summer compared to this time of year! It’s one of the reasons I don’t ride the G much in winter. I can’t afford the bloody fuel!

Also the Mana has a nice, big, fairing to nestle behind. It’ll be even nicer when I get round to sticking heated grips on it!

beetle wrote:

No, there's no 'remembering'.

There's 'instantaneous' (ahem..) fuel consumption calculation based on injector pulse widths, injector flow rates, acceleration enrichment correction, fuel consumption scale factor, blah, blah, more correction factors and scale factors than you can poke a stick at..with the data sent to the dash over the CAN bus with all the other pertinent stuff like RPM, speed...which the dash then crunches and displays, slightly delayed...

This is useful to know.

thank you and to everyone else who has added to my post