Fuel Gauge Accuracy

[Hughd Lurker Find all posts View Profile Close Hughd]

I have searched the forum, and I can't find anything on the ACCURACY of the Prado fuel gauge.
You might think that in the days of ABS, Stability Control and DAT that it would be possible to make a fuel gauge that was even roughly accurate to maybe plus or minus 20 litres. Mine sits around the full mark for the first 320 km, then drops to just above three quarters over the next 20 km. Then it stays there for about 150 km before dropping to just over half - where it stays for another age.
The service guys say they all do that - do they?
H

[samo Addicted PP Member Find all posts View Profile Close samo]

Re: Fuel Gauge Accuracy

mine is fairly accurate throughout the range, fuel light comes on ive got 15 to 20l left. cheers samo

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

Re: Fuel Gauge Accuracy

There was a heap of this discussion under the 120 diesel engine section.

Mine got through 107 litres before switching and explains why I always get more mileage out of the first tank.

[Malcur Junior Member Find all posts View Profile Close Malcur]

Re: Fuel Gauge Accuracy

Mine varies a bit. The most I have done before the 2nd tank light comes on is 633km. Yesterday the light came on afyter 500km. It seems to vary, generally I get 600+km but a few times the light has come on under 500km. In all cases, I end up with the same consumption by the time I fill the two tanks. I have also noticed that if the light comes on early, then the guage for the 2nd tank stays at the top for a longer time.

I assume this means the guage itself is reasonably accurate, but the 2nd tank light is not so accurate.

Mal :? :? :?

[Bankrupt Member Find all posts View Profile Close Bankrupt]

Re: Fuel Gauge Accuracy

Only on my first ever tank but I'm sure the guage is stuffed. Ive done 500km and haven't even used a 1/4 of a tank yet

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Re: Fuel Gauge Accuracy

Only on my first ever tank but I'm sure the guage is stuffed. Ive done 500km and haven't even used a 1/4 of a tank yet

You've used 1/2 tank... on the 1st tank the gauge only uses half its scale.


Mick

[Bankrupt Member Find all posts View Profile Close Bankrupt]

Re: Fuel Gauge Accuracy

650kms now and just about 1/4 of the tank used...at this rate I should get approx 4200KM from 180ltrs

Must have bought the 3ltr Fresh Air Model

[Corigator Avid PP Poster! Find all posts View Profile Close Corigator]

Re: Fuel Gauge Accuracy

Bankrupt - You'll find it goes down a little quicker from there. But you may well get 2,00km if you're careful with the fun peddle. -

Let us know how many k's you are at when the fuel light comes on...

Thats the joy of a Prado turbo diesel

[Bankrupt Member Find all posts View Profile Close Bankrupt]

Re: Fuel Gauge Accuracy

Bankrupt - You'll find it goes down a little quicker from there. But you may well get 2,00km if you're careful with the fun peddle. -

Let us know how many k's you are at when the fuel light comes on...

Thats the joy of a Prado turbo diesel

First refil took 150ltrs and did 1370km. Car is new, has tracklander cage etc on roof and did a fair bit of dune / beach work in that 1370km.

Wasn't too bad I thought.

[Jono_Insomniac Lurker Find all posts View Profile Close Jono_Insomniac]

Re: Fuel Gauge Accuracy

yeah i have noticed with my 2004 gx that the first tank only uses the first half of the gauge, and at about 85lt the 2nd tank kicks in and uses the whole gauge. i got 1350km and still had 20lt left. my first big trip and was playing it careful

[Chewie Lurker Find all posts View Profile Close Chewie]

Re: Fuel Gauge Accuracy

Not sure if it's been mentioned already but I've been informed that the fuel system (in a 4Lt V6) is pressurised from the second tank. Ie: every time you start the motor, you're using fuel from the 2nd tank.
I was noticing that I always seemed to get more K's out of the first tank - when compared to the second. Say around 750km from 1st and 600 from the 2nd.
Now, after a bit of "bush testing", I get roughly equal k's out of each tank by not turning off unless re-fuelling or if I'm going away from the car. Makes all the difference on long trips

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Re: Fuel Gauge Accuracy

Not sure if it's been mentioned already but I've been informed that the fuel system (in a 4Lt V6) is pressurised from the second tank. Ie: every time you start the motor, you're using fuel from the 2nd tank.

Not quite... here's a better explanation from another threat:

[quote:1uovt20q]Mine seems to get a lot more from the first tank than from the second

The reason for this is in the way the fuel system works. You don't have two seperate tanks that are switched between (like the 90 series).

The second tank should be thought of as an "extension"to the main tank

The system works by taking fuel from the main tank and pumping it to the injection pump or fuel rail (depending on engine type)

The return line from the engine goes through a "Jet pump" which is in the main tank but sucks fuel from second tank. (more fuel is pumped than used by the engine for lubrication and cooling the injection system etc)

The jet pump pumps fuel to the main tank and tops it up whenever fuel is flowing (Engine running)

A jet pump uses no moving parts. Think of it as a funnel with a high pressue jet firing into the middle of it. The pressure stream draws in surrounding fuel into a lower pressure, higher volume stream.

So.... to pump fuel out of the second tank you are in fact using an amount of fuel from the main one to make the jet pump work.

Here's a diagram of a jet pump which will hopefully help explain how it works:



Mick[/quote:1uovt20q]