fuel warning light - Page 3

T-Cut · 21st February 2018, 10:00

Quote:

Originally Posted by Steve42

Last week my tank was very low.
Gauge was nearly on 0 and dashboard said I had 3 miles in the tank.
Started the car up and started to de-ice the car.
After a few min it had gone from 3 miles to 10 miles .
I had 10 miles to get home so thought I would risk it .
Drove the 10 miles home and got to the garage.
Stopped and looked at the dashboard I still had 20 miles left in the tank .

There's a clear logic in that, but did the gauge needle rise in line with the new range calculation?

TC

kelvo · 4th March 2018, 18:32

I'm still getting used to the fuel gauge on my new V6, at times I do wonder if it intends to give me a heart attack through horrendous fuel consumption - there seems to be little movement at first and then suddenly seems to drop, it doesn't seem linear with mileage. Compared to my previous V6 I knew I would get around 300 miles on a full tank but seem to be getting less with this one.

Not being previously aware of the diagnostic function on the dashboard I have been doing a bit of calculation.

The fuel light came on the other day and the range has varied from 50 - 10 miles, when I got the car out of the garage today, the gauge was on zero and range was zero.

I used the test function and got the following readings.

6.0 _ _0030
1_6.2 _ _ 0000

I presume from this that approx. 3 litres was left in the tank.

I took the car and refuelled it and it took 57 litres to fill, I know the tank is 65 litres so presume that 8 litres remained.

Interestingly after refuelling I checked the diagnostics and got

6.0 _ _ 5700

I would have expected this to read nearer 60 or 65 if the tank was full?

Out of habit, I have always reset the trip counter after refuelling and using my calculation I am getting a fuel consumption of 21.3 mpg, this kind of figures as I mainly do short runs around town.

I am still a bit wary of the fuel gauge but using the trip counter and fill to brim I am a bit happier that my fuel consumption is not as bad as led to believe. Having now got a car with IPK, this is showing fuel consumption of around 22 mpg so think this tallies.

HarryM1BYT · 4th March 2018, 21:06

You need to keep in mind, how the fuel level sensors work. They are floats attached to arms, which operate a rheostat or variable resistor. The floats can never follow the level down the the very bottom of the tank, nor to the very top, due to the thickness of the floats. Besides, they are even less able to follow the extra fuel in the filler neck above the top of the tank.

4th March 2018, 21:06	#23
HarryM1BYT This is my second home 75 Contemporary SE Mk II 2004 Man. Sal. CDTi 135ps, FBH on red diesel, WinCE6 DD Join Date: May 2010 Location: Leeds Posts: 17,273 Thanks: 2,160 Thanked 2,061 Times in 1,586 Posts	You need to keep in mind, how the fuel level sensors work. They are floats attached to arms, which operate a rheostat or variable resistor. The floats can never follow the level down the the very bottom of the tank, nor to the very top, due to the thickness of the floats. Besides, they are even less able to follow the extra fuel in the filler neck above the top of the tank. __________________ Harry How To's and items I offer for free, or just to cover the cost of my expenses... http://www.the75andztclub.co.uk/foru...40#post1764540 Fix a poor handbrake; DIY ABS diagnostic unit; Loan of the spanner needed to change the CDT belts; free OBD diagnostics +MAF; Correct Bosch MAF cheap; DVB-T install in an ex-hi-line system; DD install with a HK amp; FBH servicing. I've taken a vow of poverty. To annoy me, send money.

4th March 2018, 18:32	#22
kelvo Gets stuck in MG ZT 190 SE Join Date: Oct 2017 Location: Chatham, Kent Posts: 569 Thanks: 22 Thanked 163 Times in 135 Posts	I'm still getting used to the fuel gauge on my new V6, at times I do wonder if it intends to give me a heart attack through horrendous fuel consumption - there seems to be little movement at first and then suddenly seems to drop, it doesn't seem linear with mileage. Compared to my previous V6 I knew I would get around 300 miles on a full tank but seem to be getting less with this one. Not being previously aware of the diagnostic function on the dashboard I have been doing a bit of calculation. The fuel light came on the other day and the range has varied from 50 - 10 miles, when I got the car out of the garage today, the gauge was on zero and range was zero. I used the test function and got the following readings. 6.0 _ _0030 1_6.2 _ _ 0000 I presume from this that approx. 3 litres was left in the tank. I took the car and refuelled it and it took 57 litres to fill, I know the tank is 65 litres so presume that 8 litres remained. Interestingly after refuelling I checked the diagnostics and got 6.0 _ _ 5700 I would have expected this to read nearer 60 or 65 if the tank was full? Out of habit, I have always reset the trip counter after refuelling and using my calculation I am getting a fuel consumption of 21.3 mpg, this kind of figures as I mainly do short runs around town. I am still a bit wary of the fuel gauge but using the trip counter and fill to brim I am a bit happier that my fuel consumption is not as bad as led to believe. Having now got a car with IPK, this is showing fuel consumption of around 22 mpg so think this tallies.