How to set fuel consumption properly?

I haven’t managed to make average fuel consumption work properly. So I have set all the necessary information (engine size, fuel type, engine power, car weight), my car also has MAF sensor. However, RealDash displays average fuel consumption 25 liters per 100 km, while car’s built-in trip computer displays 10 liters. I wonder if injection size affects this info? (I haven’t set injection size, since it’s impossible to find this info for my engine). I guess the only thing left to do is fuel correction?

what car? which engine? usually for 4 cylinders the number of injections per cycle is 1!

Hello, the size of the injector is fundamental for the calculation, you can use this page to calculate more or less the size of the injectors based on the engine power

in Target Crank HP place the engine power of your vehicle

and in Max Duty Cycle% I would put 85 - 90%, press the calculate button. at the bottom the size appears in lb / h and cc / min

I hope the translation is understood

It depends on the engine, in some cases not very advanced engines have semi-sequential injection, what it does is inject 2 times per cycle, a modern engine, it should be 1 injection per cycle

Toyota’s 1KD-FTV. Yeah, it’s 4 cylinders engine, so I guess injections per cycle number is 1. However, I haven’t managed to find injection size number still. Looks like Toyota just doesn’t provide this kind of info for their engines.

Yeah, thank you for this site!
I tried different numbers (namely, 200, 400, 600, 800). And it still displays wrong info, it doesn’t even change anything. It shows exactly same fuel consumption for any injection size number. I’m going try again today, will let you know of the results.

If your vehicle is not sending injector pulse widths, then injector size is not used for calculations. Your vehicle probably uses MAF for calculations.

So, does it mean that the only solution here is fuel correction in garage tab?

In MAF calculations, the engine size (cc) and VE-value also affect the calculations. And then, of course you can use the correction factor.

Yeah, 100km of tests behind and it’s finally working correctly. Thank u a lot!!!

For all the 1KD-FTV (3.0L, 173hp) owners, you need to set the following values:

  1. Engine size: 2982
  2. Value Efficency: 70%
  3. Mechanical Efficiency: 50%
  4. Fuel Consumption correction factor: 0.22

I guess fuel correction number may be a little bit different (0.2-0.25) if you have a stock engine. I set 0.22, since my engine is chip-tuned to 220 hp.

I am not sure if my 320d is sending injector pulse widths but MAF data is coming. Currently, I have put 19 as injector size based on some google search. What should I put it as? Based on DanielGaviria’s link it should be 26. I can try with that. But if RD is not using injector size any number doesn’t matter? It is not accepting blank or 0. Should I leave it as 1 and check?

As infomed earlier I am not able to leave the FCC at a fixed value. Based on trial and error, for city rides it is set around 0.34 and for highways I am having to increase it to 0.47 to kind of match the kmpl reading of my trip computer. Can have an action button to change FCC on the fly without going into garage?

@ilezg How did you arrive at the above values based on 100 km testing. I have still not got a fix after 8000 km of trial and error :-). I have set Vol eff at 100% and Mech eff at 95% (default value) and still I am not able to arrive at the correct FCC number. Is your FCC fixed at 0.22 for both city and highway drives? If yes, my only hope is to remove injector size and try. Have you entered 1 for injector size?


Injector size is only used if RealDash receives injector pulse width data from the vehicle.

Is there a way to check it, like we did for MAF?

Can have an action button to change FCC on the fly without going into garage?

Check what?

Changing the fuel consumption correction on the fly is not a good idea. Rather, we would need to find the actual issue and fix that.

I was wondering if there is a text gauge I can set up to check whether it receiving injector pulse width data like we did for MAF.

Sure, there are inputs for Injector Pulse Width 1 & 2.

Both of them are remaining 0 while driving, which means RD is not receiving IPW data. So I have to play around with FCC, Vol efficiency and Mech efficiency.