Hi All

I Have a question about the trip computer and how it works

I have been told that if fuel was drained out of my tank it would change the mpg on the trip computer !

I am aware that it will change the distance available as it can sense the drop in fuel in the tank 

Any input on this will be much appreciated 

Bruce

Welcome to the forum Bruce, you'll find the members on here are a friendly and helpful bunch :) 

My key question is how or why has your tank been drained? 

Obviously the fuel gauge will show a lower amount of fuel and the same for the distance to empty on the computer. But I'm unsure about the mpg. On the one hand it should because the car has done less miles with the fuel however if the ignition and computer were off then the car may not twig about about the loss of fuel in relation to mpg if that makes sense. The car may use the current fuel.level as reference.

Hope that all makes sense.

Cheers

Steve

Hi Steve

Tank was drained by 1/4 to allow for new pump to be fitted

Car was  on 47.1mpg average over last 8000 miles when it went in and on 41.1 when it came out and trip had not been reset!?

Not sure how this is possible 

Any ideas

Bruce

Hmm, truthfully I'm.at a loss. Have you asked the garage about it? 

Cheers

Steve

yes they gave me the usual BS 

I need to find out if the car uses the sensor in the fuel tank to calculate mpg 

I can't think it would otherwise when you fill it up your mpg would go up!

Does that make sense?

Bruce

Yes it does. Using the sensor it will calcualte miles left to empty 

Thanks 

I understand that bit but can it affect the mpg on your trip computer?

Bruce

Yes. As its missing info trip comp will go crazy 

Its like A + B + C = D 

Now take away imput B and it = ? 

Its math :) 

got it 

Thanks for your help

Bruce

I'm glad somebody was able to explain this to you as it just bought a smile to my face, in my case if you just swap the 4 round with the second number in your mpg figures you've pretty much got my mpg, nobody has to touch my tank it just drains itself. 

Or ... i might be wrong lol

I cannot remember if mpg worked when a fuel sender failed on my car 2 years ago