Which would trust more, trip computer or fuel gauge?

OSI

Quick question regarding figuring out how much fuel you have left etc...

I've noticed since I got my car (1.6 Hyundai Coupe) that when the fuel light comes on, the trip computer says I have around 60-80 miles left in the tank. And when the needle is pointing at empty it still says I have a good 40+. So even though the gauge says the tank is empty, the computer seems to say I've a good gallon and a bit left.

My question is, how accurate is the trip computer for figuring out how much fuel you have left? ie, if it says I have 40+ miles of fuel left, can I feel safe in the knowledge that I'll make it home, or should I be dashing for the nearest petrol station as the gauge is about to bend in half it's that low.

Obviously I could try and find out, but getting stuck in the middle of the country on the way home isn't an ideal situation..

Anan1

The only sure way to find out is to run it to empty.:)

EPM

My trip computer bases distance to empty on the fuel consumption since the last reset - most do. It can drop fairly quickly though after coming off a motorway slip road say where you need to floor it.

But it really isn't a good idea anyway leaving the car go that low (easier said than done I know). Can suck all sorts of crap from the bottom of the fuel tank into the filter.

mickdw

The trip computer can only base the calcs on previous averages so if it says 40 miles left, you will run out alot quicker than that if drive hard for the next few miles. All this is assuming its actually accurate. My current car will go down to zero (forget to fuel in time once) without running out while an alfa 166 I used to have ran out with 40 miles remaining on the computer so not worth the hassle of guessing imo, just fill up in good time.... you dont lose anything by filling up good & early

woody33

And I'm told that the fuel pump is lubricated by the petrol and if the level is low they can run dry intermittently when you corner, causing them to fail. Not that I always follow that advice myself, you understand.

Cookie_Monster

I've seen my trip computer tell me I have 60 miles left and 20 miles later I have 65 left

Always use gauge to judge but when it's down to zero will lokk at the remaining miles to judge if nessicary

mailforkev

I prefer to use the trip display but in my Volvo the fuel warning light comes on at a minimum of 120km left still displaying, last night it came on at 140km left on the trip.

It's very disconcerting driving around with the fuel warning light on even if the car says there's ages left to go.

Hellrazer

When I worked in one dealer we used to have a bet on how far you`d get "on the light" so to speak.

Best ever was an Accent showing 50 km left and I got to Wexford and back on it--about 130 km.Think the best in a coupe was about 80-90km when it was showing 50 left.

Always get the impression that the manufacturers make the fuel light come on with loads left in order to stop peeps running out all the time.

Del2005

Hellrazer wrote: »

Always get the impression that the manufacturers make the fuel light come on with loads left in order to stop peeps running out all the time.

There's very little point in the light coming on and then running out. It's a warning light that you are running low so you need fuel soon.

zilog_jones

Hellrazer wrote: »

Always get the impression that the manufacturers make the fuel light come on with loads left in order to stop peeps running out all the time.

No trip computers or fancy "lights" in my car
However, I have let it go down to the empty line on the fuel gauge and was able to fill the 40 litre tank with 35 litres of petrol. At the beginning of the red line there is still a good 10 litres left in the tank.

Del2005

zilog_jones wrote: »

No trip computers or fancy "lights" in my car
However, I have let it go down to the empty line on the fuel gauge and was able to fill the 40 litre tank with 35 litres of petrol. At the beginning of the red line there is still a good 10 litres left in the tank.

That all depends on the car/tank, I've often put more then 40l of petrol into my 40l tank even when it's not empty. But my car will do ~200 miles on the 1st quarter mark and then only gets about 150 miles more to the 3rd quarter mark.

bmw535d

the best way to find out is to find out the size of your tank in liters. as soon as the light comes on, fill it to the brim,see how many liters you get in,take away about 1 to compensate for the tube going into the take,subtract the amount you've put in from the size of the tank,you then know how much is left in the tank when the light comes on, you can then work out how far you will get based on you average consumption