mpg

[jamema]

hi all i have a 2002 90 hdi 2ltr,owning it now for 3 months,my mpg wont go above 34.9 and thats driving like a grandad..
i often service it and treat it with wynns egr and fuel cleaner,ive had it plugged in and no faults coming up....i went on a 200mile motorway hike and it did manage 36.5 ,thats sticking to around 60 - 70 mph...

why is my mpg so low....help...

[Gibbo]

Brakes binding? Tyres? Excess weight in the car?

[jamema]

no none of them gibbo...

[jmkent]

Is that the trip computer reading, or a manual calc?

If its the trip, maybe worth trying again with a manual calc just to check the trip is working correctly.

[jamema]

thats with the trip computer...

[icepac21]

Originally Posted by jamema

thats with the trip computer...

Hey, please can someone explain how to work out the MPG yourself?

[jmkent]

Originally Posted by icepac21

Hey, please can someone explain how to work out the MPG yourself?

Reset the mileage trip, and fill the car up with fuel.
Drive until down the 1/4 tank or so.
Refil the tank again, noting how many litres you put in.
Make a note of how many miles you've driven in that time.
Then calculate mpg using: (miles / litres) * 4.54

Then you're done

Its basically what the trip is doing, but just a manual check. I've checked mine before, and trip was within 0.5mpg of the manual calc, so shows its working OK.

[john_h]

i also find your MPG will go down if you have lost pressure in your leak back pipes on your injector, also you loose alot of fuel...

for a while ive been running on around 37mpg for a while, changed the leakback pipes and replaced the clips its gone up to 60mpg! must of been a blockage or pressure loss...that finally made the pipe blow off and dump fuel in the engine bay and drip onto the roads. class when i took it to work and the fitters called all the buses in to check all of them for a diesel leak test...never told them it was my car

[clanless]

The distance between each mark on the fuel gauge is 7.5 litres or 1.65 gallons. If you get 99 miles between each mark you are getting 60 mpg.

This is quite hard to achieve, but it can be done. You use something like 10% more fuel travelling at 70 as opposed to 60 - something like that anyway, its a HUGE difference in consumption for relatively little speed gain.

Its not just speed as well, remember to change up before 2k rev's, to accelerate gently and to take your foot off the accelerator to slow down when approaching a junction as opposed to slamming on the brakes.

[jamema]

Ill check leak off pipes then and do a manual mph
figure...