Anyone know if the MINI OBC will accept correction factors to adjust the typical generous high MPG readings? How is it done? BMW's OBCs have these and the accuracy can be corrected to dead-on.

 

Bump. MINI service manager tells me that MINI's mpg values cannot be adjusted or corrected. Anyone know any different? BMW and Audi have the ability to change the factor. Why wouldn't MINI?

 

I would think NCS expert would do the trick...

 

There is NO WAY to get it to be "dead-on".

Yes there are other makes of cars that are much closer but even those can be as much as 1-2 MPG off at times.

The way the MINI one works is based on a number of factors. The instantaneous is based on fuel passing a sensor vs speed. The non instantaneous is based on readings at approximately 18 mile intervals. Thus if you run the car hard for say 50 miles and then easy for 50 miles it will be different than if you run the car hard for 100 miles or easy for 100 miles. But at any rate an interval of 18 miles is really a long interval to get average reading to be anything closer that maybe 5MPG.

So I would say that NCS Expert probably would not be able to make any adjustments to this.

And maybe of note to you it that if you reset it every time you get gas you will notice that it is much farther off than if you let it calculate over 10 or more tanks.

Mine has not been reset for over 15 tanks of gas and it is with in about 1/2 MPG of the overall average for those 15+ tanks. I do know that if i reset it the reading will be off by maybe as much as 3-4 MPG.

 

Thanks for your response Schatzy62. I have two BMWs and I have adjusted them myself to both read within 0.1 or 0.2 mpg at each fill up. I have a new Audi that I just had in for service and they adjusted it (not user adjustable). I'll be calculating each tank manually as I do with all my cars all the time, and we'll see what happens. My MINI, as in all the other cars, reads too high to the tune of 2-3 mpg, tank after tank after tank, in all types of driving. I think this is a farce and the manufacturers are playing with the public to make their cars seem like they get better mileage than they do. They understand that most people won't calculate mpg manually when they have a trip computer do it for them so they won't really know its off by 5-10%, or more. I think something should be done about it and I highly doubt its a technical issue because I've never seen a car read low by 5-10% - they always read favorably to the manufacturers.

I don't agree with your position, perhaps because I don't know enough about the specific MINI technology, that the 18 mile interval is too long an interval to get more accurate. I think of it as a snapshot in time and statistically these should average out and be reasonably close especially if you have a few tanks that read high and a few read low. But ours only read too high and I'm sure MINI can do better. I am still not believing that there is no way to make a correction to the calculation that the car does. Whether its 18 mile, 5 mile or 30 mile snapshots, the calculation is off and should be correctable. Your thoughts? Any R56 MINI techs out there who can look into this a bit further?

 

The instantaneous fuel reading is probably derived based on engine speed, vehicle speed and what the oxygen sensor is telling the ECU.

Much the same way that E85 engines know that E85 is in the engine based on the O2 sensor reading.

 

My understanding is that mpg is based on the fuel injector pulse (open) time plus vehicle speed.

 

The open time for injectors is determined based on readings from the O2 sensor.

 

Yes it is. You just need to enable the hidden menu in the MMI and go to work! Loads of info about it on AZ.