Effect of Car Loading On Fuel Gauge?

[Conan]

I just got back from a three-day road trip in the Jetta. Cruised up to Montana to pick up a project car ('72 Honda AZ600) that has been languishing in storage. Turns out the car wasn't ready to tow, so I just loaded up the Jetta with whatever I could fit. I made the best mileage I've ever seen so far, just by driving 77 MPH steady across Wyoming. Coming back, the car definitely had a load on, and was riding a bit low in the back.

I got burned by this before-- one time I was towing my little Honda 600 behind a Subaru Forester. The fuel light came on, and I knew that meant I had about a forty mile reserve. Just miles after the light came on, I ran out of gas. In the middle of nowhere, Idaho, in the middle of the night. I learned (the hard way) that a tail-heavy Subaru has no gas reserve.

Twice I had the fuel light come on during this road trip. I dashed for the closest diesel, and found that I had 2 to 2.5 gallons left. (Only took 15 gallons-- ventectomied.)

So, what is the effect of a load on your fuel capacity? I've run out of fuel once in the TDI, and don't want to do it again. Especially not in BFE Wyoming, with a maxed load of tools and valuables. And a dog.

 

[Joe_Meehan]

I have run out of fuel a couple of times. I have learned it is a lot easier and smarter to just refill when I hit half way.

I can remember when VW sold a fuel tank that fit in the spare wheel housing. I guess they can either run out of fuel or loose a tyre.

Really, why worry. Just fill up when you get to half full. It just makes life a lot easier.

 

[Conan]

Stopping every half a tank on rural road trips would mean almost certainly having to get fuel at very expensive and/or sketchy stations. I like to fill up at big truck stops when possible. I learned (the hard way) that a fuel light means you have about forty miles of range left in a Forester, or about zero if the tail is weighted down. I'm wondering about that effect in a mkiv Jetta. It seemed to be backwards from my Forester experience-- the light came on when I still had tons of diesel. I guess the only way to know true range is to run out, which I don't intend to do. The first (and hopefully, last) time I ran out, I thought it was never going to start again.

 

[MikeMars]

Ultimately the fuel tank has a flat base, and if you are on an adverse tilt (due to a hill, or heavy loading, or whatever), the last bit of fuel will not reach the fuel pump.


(Remember to increase the pressure in your rear tyres if you are heavily loaded).