Fuel consumption conundrum

cogarch

cogarch

Member
Can poor fuel consumption be a symptom of poor engine tuning? If so, what level of fuel consumption if any could justify a service under warranty?

We bought our 2005 A2 1.4 TDI in March, as a family car to replace an aging petrol Passat estate (which was averaging about 27 mpg around town). I was tempted by a hybrid but, with past experience of an A4 1.9 TDI getting up to 65 MPG on the motorway, I was looking forward to getting figures that were even better with an A2 Diesel, with superb design and handling to boot.

The design and handling are as expected, but in terms of fuel consumption I have been managing an average of 37 MPG around town and 44 MPG on the motorway (A/C on most of the time), with a maximum of 56 MPG in a controlled experiment when I filled the tank up before and after driving 100 miles at a steady 70 MPH (slowing down as necessitated by road conditions!). This was nowhere near what I had expected - I thought I might have found the reason when I discovered my tyres had been under-inflated. However the figures weren't any better when the tyres were pumped up to the recommended pressure.

It's not as if I'm lead-footed -- I pride myself on being a pretty smooth driver. The question is, are these what is to be expected for this model, and if not might there be an underlying mechanical problem?
 
Have to say in the three weeks of owning my 1.4Tdi, I'm consistently around the 52 - 56mpg (measured brim to brim), and I drive with a lead right foot. I am not a smooth driver, I generally pull away fast, so I'm pretty happy. I have noticed however that there is a wide disparity between owners, some being as low as late 30's, which for a Tdi is terrible. Can anyone shed any more light?

As a side note, I instantly went from 52mpg to 58mpg by changing the oil. ;)
 
MPG will always vary from car to car of the same make and spec, there are manufacturing tollerances involved so unless all engines and gear boxes are blueprinted they will all vary, things like external air temp made my tdi vary by up to 10mpg, in winter just squeaked past 50, easily 60 in summer, having the air con on in some cars makes a difference, it cost me 5mpg, some others it makes little difference.

Also the amount of weight in an A2 effects consumption greatly, try removing the rear seats for a week and see what difference it makes, likewise the level of stop start traffic and a whole host of other factors come into the equation.

You cannot really compare like for like as it doesn't really exist, someone living round Norwich will get better fuel than someone living in the peak district - it's the hills you know.
The only true comparison of you to drive 2 different cars on the same route at the same time, which is impossible.

However your figures do seem a little low, as mine were when I first got 'eggbert' they should improve once you're used to the cars engine, try keeping below 2k rpm and only use 1st to go 1 car length, it makes a huge difference.
Hope this helps
Mike
 
Hi Cogarch,

Just out of interest, how many MPG were you expecting to get at a steady 70MPH? The only way I can get high MPG is to drive long distances at less than 2000RPM in 5th gear.

John.
 
My previous diesel was a Pug 106 (1.5l, NA)

I used to get 60mpg whatever I did.

After a week or so with the Audi the computer is showing about 56mpg. Which considering the extra weight and performance over the Pug is not bad in my opinion.
 
In answer to your question Poor_John it's true that I haven't had the patience yet to test extended periods at 50 MPH. Maybe I was being unrealistic, but I did think that even at 70 MPH with the A2's reputation I might be able to do better than my old A4 1.9TDI, with which I remember regularly managing 65 MPG on motorway journeys. I should say that that was according to the DIS, while with my A2 I am sadly deprived of such toys and so am not only restricted to brim-to-brim but also have no real-time info to help me maximise MPG while I am driving.
 
i tried driving like that today...changeing up before or at 2000 rpm
its pretty slow progress...usually in 2nd i go to 2500 rpm or just below
do all you guys drive like that? is that the main reason why i never better
43mp locally? by the way its a Tdi
 
I tend to drive everywhere in 5th gear if above 30mph, however I regularly lead-foot it on a daily basis given the nature of the roads I drive on. I drive a mixture of 1/3 town driving and 2/3 country a-roads at about 50-60mph using cruise control.

My MPG is way higher than the figures you've experienced, but I have found that above 60mph my MPG starts to drop off due to the higher revs required.

See the link in my sig for figures

Ian
 
your A2 looks daym good....the shiznit

i normally don't like cars with aftermarket kit but must say yours looks subtle
i like the subtle understated style.

i dont know i tend to use 5th once above 40mph as it does'nt feel right its far too early..then again i think you have the Tdi 90
 
Thanks very much ;) The kit is the genuine Audi one, so it's OEM+ (that's the styling mentality I subscribe to!) - plenty of pics in the UK gallery. Mine is a TDI 75, not a 90, however it has been remapped by Revo to give circa 105BHP.. :D
 
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