fuel 'range' on trip computer seems faulty

[johnpemberton]

recently purchased a 2008 ml 280 cdi, i seem to be experiencing a small issue with the trip computers fuel 'range'

there was a small fuel leak when i first bought the car,this was promptly repaired by the garage i bought it from. the issue i have is the range readout seems to drop very severely when the car first starts and for 5/10 mins of driving, this number seems to steadily rise after a small drive and eventually seems to settle with an ammount. my question is if this is something i will just have to get used to (all my previous cars have never had this) or is there someway i can reset the computer and see if that works?

*i have read previous threads relating to the analoge fuel gauge:this seems to be working fine, moves to full when filled etc it seems to be an issue with the actual computer based range readout.

thanks in advance

 

[Chee]

Do you start your car to warm it up? Happens to mine on cold mornings, I start the car, leave it for couple of minutes there and the MPG drops to 9 which of course will reflect in the max range.

 

[whitenemesis]

The range is bound to drop in the first 5/10min driving as the mpg will be very low initially. As the engine warms up the mpg increases again and so does the range..

 

[television]

Do you start your car to warm it up? Happens to mine on cold mornings, I start the car, leave it for couple of minutes there and the MPG drops to 9 which of course will reflect in the max range.

Is that all I got my SL500 down to 2.3 mpg one cold morning.

 

[Chee]

Is that all I got my SL500 down to 2.3 mpg one cold morning.

Take your foot off the accelerator while having the Parking break on

 

[exjagman]

Is that all I got my SL500 down to 2.3 mpg one cold morning.

Was that while you were parked on that sheet of ice?

 

[exjagman]

recently purchased a 2008 ml 280 cdi, i seem to be experiencing a small issue with the trip computers fuel 'range'

there was a small fuel leak when i first bought the car,this was promptly repaired by the garage i bought it from. the issue i have is the range readout seems to drop very severely when the car first starts and for 5/10 mins of driving, this number seems to steadily rise after a small drive and eventually seems to settle with an ammount. my question is if this is something i will just have to get used to (all my previous cars have never had this) or is there someway i can reset the computer and see if that works?

*i have read previous threads relating to the analoge fuel gauge:this seems to be working fine, moves to full when filled etc it seems to be an issue with the actual computer based range readout.

thanks in advance

Your range will increase as your engine temp increases and your mpg increases, once that has happened your range will start to decrease as your mpminute increases

 

[brandwooddixon]

The range is based on current fuel consumption and so is bound to be less when cold as this is when the engine is at its most inefficient.

I think it tends to err on the side of caution as well. I've had mine down to 2 miles range and still had 4 litres in the tank!

 

[mersum1es]

That feature annoyed me, so I've mod mine to show liters left, much easier to follow (even also that reading is cautious, tank has actually few liters more than shown in gauge).

 

[Chee]

The tank itself should be as big as on the papers. The fuel in the system would make the difference.

Sent from my GT-I9505 using Tapatalk

 

[mannikon]

That feature annoyed me, so I've mod mine to show liters left, much easier to follow (even also that reading is cautious, tank has actually few liters more than shown in gauge).

Sounds like a useful mod. How was it done?

 

[mersum1es]

Sounds like a useful mod. How was it done?

Non-UK/US car easily; just enabling the option by star in cluster version coding list

 

[Troon]

The miles remaining display in my car is terrible. Although I understand the maths that's likely to be causing the numbers I get, it's silly and much worse than any other car I've used.

I often set off from work with 47 miles to go and less range than that showing — yet I get home with more than 60 miles remaining (no, I haven't filled up on the way).

 

[johnpemberton]

cheers all for responses!

 

[Irresistance]

From my experience the range calculator takes about the last 10 minutes MPG as average and applies this to the amount of fuel it believes is in the tank.

When the tank is up to 75% full, I am tempted to believe it is pessimistic (it shows more fuel than there actually is) and when it is close to empty it tends to be optimistic - ie, if it says 10 liters it's actually 12 or so. At least, that's how it seems to work after observing it with near OCD-frequency for 5 years on the W210 (and since August on the W220)