Fuel guage reading not compliant!

[Charles H]

Easier to just remove the sender and move the arm connected to the wiring and watch the gauge. Cheaper too!

[Dave B]

I guess i will just go and fill the Jerry can with another 3 gallon and pop that in - at least then if the sender is reading correct i should then read at least way over half !!!!
Regards, Nige.

Be careful not to put too much in, in case the sender unit needs to come out again!

[Forkie]

Well for me it is just a case of ' how comes in all recent scenarios the gauge reads just over a quarter ' !!!!
Well today down here was a rare decent day - time for another run out - avoiding all the salted main roads of course
Only did around 10 miles at best locally - fuel light starts shining when the gauge hit the quarter mark - . Ok so i got one rich carb and she is not running up to speed correctly but knowing there is a fair bit of fuel in the tank that surprised me. I choose to ignore the flickering light . Parked her back up in her nest after our local run about and decided to go chuck another 3 gallon in and see what it reads then - so i've now got (according to the gauge , engine running) just under half a tank!! At least it is a different reading.
Nice to think it has finally moved from 'just over a quarter', so i do think now that the level it was at a few days ago did just happened to be the same as the lay up level, but i also think the gauge is reading lower than it actually should read, but that is just my opinion.

[iani]

Well for me it is just a case of ' how comes in all recent scenarios the gauge reads just over a quarter ' !!!!
Well today down here was a rare decent day - time for another run out - avoiding all the salted main roads of course
Only did around 10 miles at best locally - fuel light starts shining when the gauge hit the quarter mark - . Ok so i got one rich carb and she is not running up to speed correctly but knowing there is a fair bit of fuel in the tank that surprised me. I choose to ignore the flickering light . Parked her back up in her nest after our local run about and decided to go chuck another 3 gallon in and see what it reads then - so i've now got (according to the gauge , engine running) just under half a tank!! At least it is a different reading.
Nice to think it has finally moved from 'just over a quarter', so i do think now that the level it was at a few days ago did just happened to be the same as the lay up level, but i also think the gauge is reading lower than it actually should read, but that is just my opinion.

You have to learn the behaviour of the fuel gauge in every old car, I've never had one that gave anything like the same mileage quarter to quarter, once you know how it behaves you can work out how many miles to expect on the readings and take it from there.

[Forkie]

That is a really fair point Ian. Even the wife said earlier we are now all used to driving cars eons away from the 2000 range, with much more direct info. Maybe i am just so far out of touch now with it, after such a long period , i am expecting too much !!!!
0r in another way - am so used to the moderns, i am expecting the same from the 2500, which of course is silly !

[johnnydog]

The 'book' states that the low fuel light should start to illuminate (flash?) with two gallons of fuel remaining, and remain on constantly when there is one gallon left in the tank
The low fuel warning is greatly affected by the vehicle movement, and it can start to illuminate on the move with more than a 1/4 tank of fuel, so I wouldn't rely on the low fuel light or fuel gauge indication at all - as said you get to know with your own Triumph when is the time to refuel as the gauge information etc varies significantly from one Triumph to another.
I had an S years ago that actually ran out of fuel when the gauge was reading between 1/4 and empty......

[Charles H]

From experience, the top 'half' of the tank takes ages to use, the bottom 'half' much less so. The sender is just a float resistor moving on an arc. The arm moves very little at the top of its stroke compared to the bottom. This is exacerbated with the shape of the tank. The volume of the top 'half' is greater than the bottom 'half' because it has a sump area on the estate. Worse on the saloons which taper at the sides to clear the suspension turrets.
Sounds like you have a proper working system now.

[Forkie]

Yes Charles, i agree on that point that most tanks seem to hold a good reading for longer in the top half than in the lower !!! I guess it is my own fault for not driving a classic for so long, and forgetting how the behave !!! I don't ever remember seeing the fuel light before, so i must of always kept it full
Based on my last week or so, and John's comment, i think i will assume just over a quarter is empty - time to refill !! And yes hopefully that is one small issue sorted. Wish i could say the same fox the autobox - i think i have sussed it today

[Mike Stevens]

Estates (and Stags) do start to flash the low fuel light way before you think they should due to the low, flat shape of the tank. As others have said you just need to get used to what the readings/flashing say.

Yes, GND = ground or Earth or in this case the body of the car which is battery negative, or should be. Earlier cars would of course be battery positive, but you don't need to worry about that as an ''S' should definitely be battery negative to the body. Sorry for any confusion caused. The sender wire colour should be Green/Black and the low fuel switch Green/Orange, according to the book! However, quite which 1/4" tab on the sender is which is not shown!

[Forkie]

Hi Mike
The 1/4" tab you mention - are you referring to my W and T remarks? I was just reading any info i could from the face of the sender unit. I know it would be an original part - EVERTHING on this car was original - believe me I think the only receipt for ' replacement parts' i have is for an mot failure in the late 80's/early 90's ( cannot remember exactly without checking) was for rear brake cylinders as the handbrake was 'below requirements'
P.S. - been having a bit of a catch up on here, slowly.... have come across your P.I. pics on the 'Spit ' ....
Regards,Nige