Miles to empty- how does it work?

[heatdev]

Hello All,

I've put a few hundred miles on the car recently. New plugs, and coils, oil change new axel back exhaust.

The car ran with new vigor, power like never before. Three days later, everything seemed to settle into a between before and after. Less pep. I noticed that whenever the gas my miles to empty would drop from 150 to 55. At speeds above 80, the miles to empty would rise dramatically. On a full tank, mile to empty would read above 400, after a few minutes, the reading goes to 190. What is going on here? How is the reading measured? I sometimes get a code for an evap leak, but I haven't found the source.

Thanks!

[abscate]

I’ve never seen the algorithm for the miles to entry but I suspect it resets when you fill the tank. The numbers will fluctuate all over the place until the car has run some miles and figured out how much fuel you have in the tank and what your average mpg is. It does not use the same average mpg that is displayed on the computer, I’ve played with this when bored in a long trip.

Going down a big hill, you can reset the average mpg, which will then max at 99.9 mpg, but miles to empty won’t change.

All of these are integrating the fuel injector time to determine fuel used, I believe.

[heatdev]

Thanks for the reply. I wish I understood this area better. It's always been close to accurate. Odd changes make me nervous. I'll keep searching for more information. Wonder if vida would help here.

[rspi]

If you are referring to the 2000 MY, it has 2 floats, on in each side of the tank. Sounds like one said maybe going bad.

[FlyingVolvo]

From the manual:

"Shows the approximate distance which can be driven on the fuel remaining in the tank, calculated on the basis of the average fuel consumption during the last 12 miles (20 km) driven and the amount of fuel remaining in the tank at the time of the reading."

As far as why it's varying to much for you, I'm not sure. I would do a few tanks and record exact mileage based on distance and fuel you put in. It could be bad level senders.

[wizechatmgr]

If you have VIDA, pull the terminals off the battery. Let it sit for a couple minutes with ignition on. Turn ignition back off. Reinstall battery clamps. Take the car for a 10-20 mile ride AFTER you fill the tank. If you have a bad fuel level sensor, VIDA should have the code for it stored now.

How do I know? I have a bad sensor. I'm not going to drop the tank over it until both are bad.

[heatdev]

Thanks for the reply! I don't have VIDA, maybe down the road.

[abscate]

From the manual:

"Shows the approximate distance which can be driven on the fuel remaining in the tank, calculated on the basis of the average fuel consumption during the last 12 miles (20 km) driven and the amount of fuel remaining in the tank at the time of the reading."

As far as why it's varying to much for you, I'm not sure. I would do a few tanks and record exact mileage based on distance and fuel you put in. It could be bad level senders.

You’ve shutoff a perfectly good chance for an internet rant with a manual reference. Is this allowed?

[FlyingVolvo]

From the manual:

"Shows the approximate distance which can be driven on the fuel remaining in the tank, calculated on the basis of the average fuel consumption during the last 12 miles (20 km) driven and the amount of fuel remaining in the tank at the time of the reading."

As far as why it's varying to much for you, I'm not sure. I would do a few tanks and record exact mileage based on distance and fuel you put in. It could be bad level senders.

You’ve shutoff a perfectly good chance for an internet rant with a manual reference. Is this allowed?

I can go get some pitchforks and torches if you'd like!

[abscate]

M56....m56...m56...m56....