VR fuel ecomony 5.5 litres per 100k

[john230873]

Found a new thing last night. Coming back from a long trip notice that my fuel per 100 km was reading 5.5 litres driving at 100kmh, normally this is at 8.5 to 9 litres per 100 km.

Turn out that each time I turned my high beams lights is when my fuel per 100km went to 5.5 litres.:hit: If any thing the fuel per 100ks should go up.

Trying to track down what is going on someone has suggested the alternator might not be producing top performance and when I turn my high beams on the fuel pump might not be getting enough power and the fuel pressure is dropped causing the drop in litres per 100ks.

Has anyone else had this?

 

[Fatboy]

5.5 L / 100km? That is a figure a little hyundai would be proud of. I think something is wrong there.

Also if your fuel pump was not giving you enough fuel, I'm sure you would know about it going at 100 kmh. Good luck finding the cause!

 

[Fekason]

Lcd?

Could it be that the LCD on the trip computer is on the way out?

5 is 8 minus two lines on the left.

 

[john230873]

No it not that becuase I turned the high beams off and the computer rose back to 8.9

 

[hako]

I'm with Fekason and the digits - brilliant off-centre deduction.

 

[Fatboy]

But the OP is saying the digit 8 is being displayed fine.

 

[hako]

Does anyone know exactly how the fuel consumption is measured? - is it flow or pressure or what.

 

[john230873]

I did some more testing tonight and found the more load I put on the electronics the more the Lper100km dropped.

 

[Fekason]

Measurements.

I believe that the fuel consumption takes readings for distance from a transducer (I think) at the transmission, and fuel flow based on fuel injector pulses registered at the computer.

Can be calibrated to be very accurate, but is reasonably close "out of the box".

 

[hako]

I believe that the fuel consumption takes readings for distance from a transducer (I think) at the transmission, and fuel flow based on fuel injector pulses registered at the computer.

Can be calibrated to be very accurate, but is reasonably close "out of the box".

Thanks Fekason. Regards