Long road trip, gas mileage

[jimnkaran]

Left today on a long road trip, 1628 miles one way. From New Mexico to Kentucky. Just filled up and got a big surprise on my mileage. I went 257.8 miles on 5.1 gallons of gas. And I did top it off as much as I could after the auto stop kicked in on the pump. I have been getting about 45 mpg with part road and part city but this tank was all road miles. Sure hope it holds up that way. Would love to make the whole trip at 50 mpg!!!! Only using 91 octane. Sure wish I had a cruise control, it will be the first thing I buy when we get back.

[a2jack]

Jim. Don't top off past the pump's auto shut off. It floods the canister and will get you a check engine light...Many of us have been there and done that.
A2Jack.

[Bum-bling-B]

Check on the next tank. I took a trip last week and had an early cutoff - tank after the great one was so good BUT it all evens out in the end.

[jimnkaran]

Originally Posted by a2jack

Jim. Don't top off past the pump's auto shut off. It floods the canister and will get you a check engine light...Many of us have been there and done that.
A2Jack.

Thanks for the heads up, didn't know why it said to not top it off.

[minimee]

Originally Posted by a2jack

Jim. Don't top off past the pump's auto shut off. It floods the canister and will get you a check engine light...Many of us have been there and done that.
A2Jack.

I did not know this...is this true with all cars? I have been "topping off" for years.

[JPaul]

Originally Posted by minimee

I did not know this...is this true with all cars? I have been "topping off" for years.

It's true at least with the smart, due to the gas tank and filler neck's design. It's stated in the Owner's Manual too. Note the location of the tank vent valve «Y58»!

[Karl Roth]

Any car with a vapor recovery system as part of the fuel system. some cars will run just fine with them flooded but they can't do the job they where designed to do. Store fuel vapor to get burned off later.
But to get back to the original point of the post your mileage will vary the biggest difference will be how you drive. my worst has been on the highway with foot to the floor. Back off just a bit and 40's...
karl

[jimvw57]

Most full size cars have the vapor canister up front by the motor. Since the Smart motor is mounted low and in the back, the canister is on the same level as the tank which can allow liquid fuel to get into it. Not a big deal if you know not to top off the tank like the other cars.

When you fill up, set the handle on the lowest rate setting and after it shuts off, wait a bit and add until it stops a second time again at the slowest setting. You wll get a ful tank and the gauge will read full. Any faster and the fuel will foam up and you won't get a full tank (or a full reading on the gauge) Took me a while to figure this out but it has worked consistantly ever since.

[Duckhunter]

When you fill up, set the handle on the lowest rate setting and after it shuts off, wait a bit and add until it stops a second time again at the slowest setting. You wll get a ful tank and the gauge will read full. Any faster and the fuel will foam up and you won't get a full tank (or a full reading on the gauge) Took me a while to figure this out but it has worked consistantly ever since

That is what I do and works for me

[PeteInLongBeach]

Many car manufacturers admonish against topping off the tank after the first click, to protect flooding of the vapor cannister. This is not particular to the smart.