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MG MGF Technical - fuel gauge lottery

This has probably been asked before, so sorry if it has.

My fuel gauge seems, er, what my old physics teacher would call 'non-linear'. I fill the car up and it says 'full'. Fine. I drive for a day and a half and it says 'half full' and I think "Bloody hell! It's guzzling the juice". It then takes three and a half days for it to creep down to the red bit and I'm happy again. I then fill the car up and it takes about 45 litres, which is about right, I think.

Is the F fuel gauge usually like this, or do others' go down more evenly? It's not a problem, as it reads 'full' when it's full and 'nearly empty' when it's nearly empty, which is, I suppose, what a fuel gauge needs to do. I just thought I'd check that this isn't a sign of a duff gauge.

Oh and it's a 2001 VVC (and it's the coolest car ever...).
David Bainbridge

I find mine to be the opposite, goes down slow to the half-way then shoots to the red. I think this is something to do with the tank design. I'm sure I have heard it described as being saddlebag shaped?



I also believe that the tank must be saddle shaped. If I go round a bend when the fuel gauge is near empty the the gauge reading goes back up to about the eighth full mark.

From past experience with my MGB I tend not to rely on the fuel gauge. In stead, each time I fill up I reset the trip meter and then refill when the trip meter gets to around 320 miles (about every other day).


looks like a dodgy sender unit. Easy warranty replacement. Male sure they put the fuel pipe back properly tho, or you could end up broken down at a distillery:-))

The tank is saddle shaped and fuel can move from one side to the other. Only shows when tank low.

I always found this gauge totally useless. Use the trip mileage counter as reference.

The fuel dials on most cars are very innacurate. On my car it is as good as on any other car I have driven, accuracy has never been a big thing with car fuel guages.

If you go round a corner the dial can change from 1/2 full to 1/4 full. As the tank is upright (behind your seat) it is quite difficult to get an accurate measurement with a float.

It is just not worth the array of sensors and calculations required to give anywhere near an accurate representation of the actual fuel level. The fuel indicator is really just a little advancement of the old fuel low indicator light in that you also know when it's full :-).

I have always used the trip meter to estimate fuel level (as Dirk Suggested). I ran a car on LPG for seven years so I had no other indicator of the amount of fuel in the tank. Mind you, at least I had the backup of being able to switch back to petrol if I ever ran out of gas.
Tony Smith

Fair enough!
David Bainbridge

Never had a problem as long as you remember with the modern plastic tanks they can be all sorts of wierd shapes so can have 'unexpected' reserve pockets - useful if you run out of fuel - in fact on my BMW bike we have found that if we lie it on to its right side after running out of fuel you actually get enough fuel foanother 'careful' 25 miles.

Ted Newman


When my tank is full, my jauge indicates only 3/4 full...
Also, i'm not sure when it is empty because i'm not confident in my jauge.
As a result i go to often at the fuel station and i'm always a bit worry when i am in the countryside where there are less and less fuel stations.

I told my problem to my garagist with other little problems i have with my F. His answer : "that's normal, all F have this problem". He says that each time for everything. Never fixed anything ;(



>>>"that's normal, all F have this problem". He says that each time for everything

But what if he's right!?!
David Bainbridge

David, Mine does the same as yours. I usually rely on the trip, and unbelievably, since fitting the K&N, I now get about another 30 miles from a tankful...weird

Kieren Gibson

>> in fact on my BMW bike we have found that if we lie it on to its right side after running out of fuel you >>actually get enough fuel foanother 'careful' 25 miles.

Ted, not so easy to do with the F, unless you are with 5 strong guys ....

Most applicabel reason for mad fuel sender indication is a wrong adjusted or sticking swimmer.

A very tricky job to get it adjusted right. Special at the new tanks from 1999 upwards, cause of less space inside the tank.

Some pictures may help to understand the problem.

This one of our German friend Wolfgang is also interesting, cause it shows the cutted tank.

As Dirkie mentioned.. LOL... just forget it if not covered under warranty.

Dieter Koennecke

This thread was discussed between 11/06/2001 and 21/06/2001

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