Thread: My MPG has gone nutts!

I've owned my 07 140bhp 2L TDI S-Line for approx 6 weeks now and I can't fathom how badly its doing for economy. I haven't got DIS so just working this out based on the trip computer on miles til fillup (which is fairly accurate) here's what I get:

I filled up £20 @ 137.9 per litre of diesel. That equals approx 14.5L/3.18 Gallons of diesel. I've only managed to get 85 miles from that. That's 26.6MPG on a 2L diesel that's been driven slowly.

I don't understand how that is possible? I've not gone above 2K rpm and I've hardly been in any traffic. Now I understand the cold weather is a factor but this is just ludicrous.

What I found totally confusing was, before I parked up one day it was at 80miles before fillup. Then when I started it up, it shot down to 50 miles.

I'm startled. Can any other owners share their experience, mpg and some advice?

Hi,

Only had my B7 for 2 months its a 140 tdi - it's been mapped to 210 and i am getting 44 on a good run

Originally Posted by jay z B

Hi,

Only had my B7 for 2 months its a 140 tdi - it's been mapped to 210 and i am getting 44 on a good run

Wow, Something has to be up for sure

mate of mine on here gphilla is having a similar issue with his he is worried injectors are on the way out.

hello,
i own the same car as you, and like you mine does not have full dis either, so what you are actually going off is range/driving style!
did you drive the 85 miles around the doors? up and down the gears, fast and slow, no cruising? if so then this is just a reflection of true diesel consumption that your car will use in these conditions!
i am sure if you put the same £20 in and pulled onto a motorway or similar dual carriageway, placed it in 6th gear and kept a steady cruising speed of for example 75mph, your range would rise and rise and rise as this is the type of situation your car gets maximum mpg from!
i found that "around the doors" my mpg is really not good at all too, but in contrast on long runs and particularly motorways the mpg is quite epic!
it also might be considering running on premium diesel rather than supermarket muck! as i found running mine on v power really does help with mpg and power, and my avant seems to like it more too! it kicks out virtually no smoke at all on this and i get noticeable more mpg"s! but sadly does cost more! a couple of tanks are required for the cars ecu to adjust is required though!

i have only completed 50k on a 57 plate - driving in 5th/6th steady is 53 - 58 mpg - around town 31/38

I find many people exaggerate their claims of super high mpg. I tend to get around 30mpg around London town, rain or shine. On a long run its 40mpg. I believe my slightly low mpg is due to a boost leak around my intercooler.

As a matter of interest from this thread i logged my trip to work today.

Car is 2005 audi a4 140 bhp with 65k miles. Distance from door to door is 15miles, consisting of 3 miles on dual carriageway (60mph), 8 miles on motorway (80mph) and 4 miles of city driving (max speed of 30mph) with about 6 sets of traffic lights.

According to DIS my combined fuel consumption was 52.9mpg. You should def get urs checked out. Hope this helps.

Last sunday i brimmed my tank then set off on the A1 and got stuch at average speed cameras, road was pretty empty so i could just cruise along at 45 - 50mph in 7th (its an auto) and my range jumped up to 755 mte with pics to prove it.

it doesn't actually do that though, i get around 50 on motorway and 33 - 44 town driving.

oh its 2.0tdi mapped to 185bhp

it should be hitting around 37-47 on a estimated average and a non stop motorway cruise 55 ?? you need to get it checked out diesel aslo use slightly more fuel in colder wheathers also

You can't work out an accurate mpg for your car without measuring it brim to brim, preferably over several tankfuls (and I mean tankful, not just the odd £20 worth of diesel here and there ). The way you've described isn't ever going to give you a meaningful figure.

Buy a small notebook to keep in the glove compartment, then note down total mileage covered per tank (actual distance) and litres used to brim it (that's diesel right up to the top of the filler pipe, not just until the foam actuates the pump shut-off). The greater the distance between fill-ups the more accurate the mpg figure. Once you've done that for, say, five tankfuls, you'll have a better idea of where you are.

I can't remember how the indicated range works, exactly (it's probably in the manual somewhere), but it's quite common for it to jump in the way you describe. My last A4 (1.9pd 130) did it and so does my current one. It's a guide to how much fuel you've got left and it tends to err on the side of caution IME.