MFA mpg reads 99.9??

[stevef182 0]

the mpg on the MFA constantly reads 99.9..obviously something is broken!! am also only getting 300 miles per tank..this seems low to me! i mean, a VR6 has a 15 gallon tank so that works out at 20 mpg! :shock:

anyone got any suggestions as to whether the two could be related, and if not, what could be causing both these problems!

Thanks!

[nocrap 0]

I've read somewhere on here what that means but cant remember.

 

Regarding the 300 miles to 1 tank, are you actually putting in 15 gallons, i.e when you go to a petrol station you are putting in 68 litres? or are are you just reading what it says on the top of the fuel metre?

 

I generally fill up in the last quarter about 45 to 50 litres of fuel. 50 litres is 11 gallons (therefore a 4 gallon reserve) this will take me just over 300 miles before its back down to the same level...my car is however a 2l 16 but does have the same size fuel tank and seems to have a similar MPG to the VR.

[carpy25 0]

99.9 means the vacuum pipe from the inlet manifold to the back of the dash clocks has a leak or is off ,had any engine work done ?

 

Rob

[joebloggsVR69 0]

300 miles on a tank? I wish I got those figures :lol:

I get about 240 (but that's driving around town..) :D

[dr_mat 0]

Didn't we go round this loop before? Pretty sure the VR's MFA mpg reading comes from the ECU, not the vacuum line.

As for working out the real mpg, better get a calculator out!

[stevef182 0]

I've read somewhere on here what that means but cant remember.

 

Regarding the 300 miles to 1 tank, are you actually putting in 15 gallons, i.e when you go to a petrol station you are putting in 68 litres? or are are you just reading what it says on the top of the fuel metre?

 

I generally fill up in the last quarter about 45 to 50 litres of fuel. 50 litres is 11 gallons (therefore a 4 gallon reserve) this will take me just over 300 miles before its back down to the same level...my car is however a 2l 16 but does have the same size fuel tank and seems to have a similar MPG to the VR.

 

no i was just going on what i read at the top of the fuel metre...i guess its normally around 50 litres i put in, but obviously i never have it completely empty..the 300 miles comes from the assumption that by the time it had gone to empty (on the gauge) it would be just over 300 miles from when the tank was full..

[stevef182 0]

Didn't we go round this loop before? Pretty sure the VR's MFA mpg reading comes from the ECU, not the vacuum line.

As for working out the real mpg, better get a calculator out!

yeah it was mentioned in another post before by someone else..i left a reply there but no proper answer was given..

so if its controlled by the ecu what could be actually causing the problem, a faulty ecu??

[dr_mat 0]

Faulty ECU, yep, could be.

 

ISTR making some comments about it, but essentially the ECU uses the road speed (as sent from the gearbox sender unit) and the injector timings (well it knows that cos it tells 'em what to do). So chances are it either thinks it's putting no fuel in, or it thinks you're doing 1000 mph everywhere all the time.

 

I guess it could be the dashboard unit too, but tbh I don't know much more detail than that, and I suspect you're just going to have to swap bits till it starts working.

 

At the very least you should get VAGCOM on it and go over the measuring blocks with a fine toothed comb and make sure they're all sensible values.

[stevef182 0]

Faulty ECU, yep, could be.

 

ISTR making some comments about it, but essentially the ECU uses the road speed (as sent from the gearbox sender unit) and the injector timings (well it knows that cos it tells 'em what to do). So chances are it either thinks it's putting no fuel in, or it thinks you're doing 1000 mph everywhere all the time.

 

I guess it could be the dashboard unit too, but tbh I don't know much more detail than that, and I suspect you're just going to have to swap bits till it starts working.

 

At the very least you should get VAGCOM on it and go over the measuring blocks with a fine toothed comb and make sure they're all sensible values.

 

with regards to the dashboard unit; everything else works so i doubt its that..but i wont rule it out..guess ill get VAGCOM on it and see what it says..thanks mate