Running out of fuel…….

[Peter Shepherd]

I have had a problem of running out of fuel although the computer reads 70 miles outstanding. The fuel gauge reads just over empty and no red light showing low on fuel. 
 

I can fill up, the tank capacity is 71 liters, put in 46.45 litres to top up to full but then only get 250 miles, with computer showing 95 miles remains in tank. So with 71 litres(15.6) gallons at 20 miles per gallon I should get a minimum of 312 miles per tank but only get 250 before I need to refill.

i know the fuel tank is a “saddleback” design so clearly something is wrong, has anyone had a similar issue or has a suggestion.

[Herbie]

Why not just try this - it'll stop all that nonsense above?

Just pick a figure (I chose 1/4 full) and simply never let it go below that. As soon as the petrol gauge begins it's descent from 1/2 towards 1/4 I'm aware that I need to put fuel in, irrespective of what the computer/gauge/light is telling me.

[ColinBarber]

2 hours ago, Peter Shepherd said:

i know the fuel tank is a “saddleback” design so clearly something is wrong

I'm not sure it is that type of design on the series III RX450h.

[Peter Shepherd]

Sorry was not vehicle specific, GS 300 Mrk 3 2005.

[Linas.P]

Pump float issue? Although that should not affect the range.

Or maybe blocked/damaged pipe between two half of the tank?

[RONNIE W HODGEKINSON]

3 hours ago, Herbie said:

Why not just try this - it'll stop all that nonsense above?

Just pick a figure (I chose 1/4 full) and simply never let it go below that. As soon as the petrol gauge begins it's descent from 1/2 towards 1/4 I'm aware that I need to put fuel in, irrespective of what the computer/gauge/light is telling me.

Yes.. I Do The Same Herb..!!

[LenT]

8 hours ago, RONNIE W HODGEKINSON said:

Yes.. I Do The Same Herb..!!

Me too!  I certainly wouldn’t let the gauge drop below 1/4 full.

However, my Lexus - like my two previous Hondas - has the little display window on the dash that presents the remaining estimated range.  

I actually find this more compelling, so anywhere between 100 and 80 miles will mean a fuel stop.

[Harrier Man]

19 hours ago, Herbie said:

Why not just try this - it'll stop all that nonsense above?

Just pick a figure (I chose 1/4 full) and simply never let it go below that. As soon as the petrol gauge begins it's descent from 1/2 towards 1/4 I'm aware that I need to put fuel in, irrespective of what the computer/gauge/light is telling me.

I do the same. I do find it mildly irritating though that my gauge reaches my one bar minimum only to find that I could have driven for significantly more miles based on the 30 something litres that I put in to fill the tank. Nothing like the range anxiety I would feel if I had a fully electric car though.

[Spock66]

But the problem described is actually running out of fuel not the accuracy of fuel gauge, estimated mileage etc so this is clearly a fault.

[Peter Shepherd]

I could run car down to the fuel gauge low fuel light coming on with 0 miles left, there is always a safety milage built in so would have enough miles to get to a petrol station. Now I carnt run past 80 to 100 miles left so there must be a fault in the fuel/tank pickup or delivery system. Just trying to find out if an easy fix or not before throwing any money at the “annoying” problem.

[ColinBarber]

21 hours ago, Peter Shepherd said:

Sorry was not vehicle specific, GS 300 Mrk 3 2005.

So yes, the GS has a saddleback design. It has two sender units, one in each subtank - I've never really understood how it works out the level correctly across the two. With the series II GS it also tried to be clever and based the fuel level on usage so it could get out of calibration, especially if you don't to large fill ups - the series III GS might do the same. Worth disconnecting the Battery to reset everything before starting to investigate if the sender units are operating correctly.