[Closed] Audi A4 Avant fuel economy

shit fuel?

I've just put a tank of tesco diesel in my A3 tdi and I'm down about 10% on usual.

You've not said what engine it has ?

Sorry 2.0 TDI 143ps, common rail I'd guess.

I've got a 2005 a4 avant 2.0 tdi.... every day mileage (to work or shops) is around 55-55mpg. Ragging it (rare) is more like 45mpg. Drove to the alps and back last winter with 3 of us and snowboarding kit, averaged 62.3mpg for the full trip (including up and down the mountains).

oh, and with a towbar rack on with 2 bikes, it won't do more than 47mpg on a motorway.

Dave

Bit crap that, should get 50+ on runs around 55 mph.

Is he driving it in 2nd gear everywhere?

Edit:

Does he have the heated mirrors on full chat all the time.. There's yer problem right there.

177PS here and generally hovers around 40mpg day to day mixed driving.

Poor fuel??

It is quite a high mileage car, possible the injectors may need a clean!

Fuel makes little or no difference to fuel economy. It's a con by the retailers and if you think otherwise you're deluding yourself.

Tell him to get the engine temperature sensors checked using VAG COM or equivalent. There are several and they're prone to failing, leading the ECU to get the fuel mixture wrong. Just because the dial says the temperature is OK doesn't mean the ECU isn't getting the wrong info.

This fixed the problem on my Passat.

2.0tdi 140 avant sline 2006 with 41k on clock here, getting around 43mpg running at 60-65mph on scottish highland A roads on longer runs. Did get 46mpg from half tank cruising around 55-60mph for a trip. Sounds as though that may be a bit low from some of the figures above. That's with regular tesco diesel...did have a read about the higher octane stuff but seened to imply it didnt make that much difference, poss a little smoother running on the engine but not much diffetence to mpg...???

Flaperon - in a Diesel fuel quality will make a massive difference to economy, yes I agree it all comes from the same place, but different companies put different additives in, Morrisons for example put a higher % of sulpher in than shell & BP.

Sensor wise, in general if there is a sensor not performing its duty correctly, i.e. coolant thermistor thinking its cold when in fact the engine is warm, you'll generally get a very high amount of smoke due to overfuelling.

Possibly try an aftermarked fuel injector cleaner in the fuel tank and see how you get on, you'd be surprised at how much a fuel injector can carbon up over 90K miles, get that cleaned out and the injector can perform as it should.

I get around 50mpg out of my 170ps A6 2.0TDi (SLine Special Edition Avant seeing as we are all bragging 😉 ) on a trip and I usually drive at around 80mph.

Is it the quattro?

Meant to say my figures above are based on tank to tank measurements/calcs and not an on board computer as believe these can be a fair bit out.

The real world figures are very different from the on board computer (DIS). My driving is mainly motorway, mileages average from 60 - 200 miles general driving at around 70 - 80. What I have found is that the real mpg value is noramlly 10% lower than indicated. I have corrected this on my A6 Avant now (VCDS).

2005 A3 20tdi Sport - Averaged low 50's
2002 A4 Avant 1.9tdi SE - Avraged high 40's
2006 A6 Saloon 20tdi SE - Averaged high 40's
2009 A5 Sport 20tdi Sline - Averaged mid 40's
2010 A6 Avant 20tdie Sline - Average mid to high 40's

Real world is that if I drive at a constant 60 then the figures jump up by about 10%. For some reason (And many other VAG drivers see this) when the temperature drops the fuel econonmy does too.

I get 50mpg out of my peugeot 306 estate that cost me £300, leaving oodles* of spare cash for more entertaining stuff...

*some

I drive a diesel & get fuel from anywhere - Morrisons, Tesco, Sainsburys, Total, Shell....and my mpg is pretty consistent. Probably around 4mpg variation with an average of 60mpg. Never bother with the 'special' stuff.

I'd get the fault codes read & see if any sensor faults show up. Does it smoke a lot on the throttle?
As above, is it the quattro? What gearbox? Manual or auto? Autotrader reckons the manual 143 diesel estate should do 53 mpg combined, 41 urban & 63 extra urban, so 50mpg doesn't sound a unreasonable expectation.

How long has he had it? Perhaps he just needs to get used to driving it. I find in my car if I try too hard to be economical, I can make things worse. I think I over labour the engine. Maybe he is doing this?

Does seem a bit low, we get mid 40's from a 2.7 TDI Quattro A6 auto. He isn't going to match a Golf 1.6 though.

Bit crap that, should get 50+ on runs around 55 mph.

Is he driving it in 2nd gear everywhere?

No, but I expect he's not driving at 55mph either, more like 70mph.

Not quattro, manual 6 speed.

When I drive with him in his Golf there was absolutely nothing I could criticise which is rare for me, as you will know if you've been here for a while 🙂

Not sure what difference to fuel the temp sensors would make. It's not a petrol, so it can't run rich or lean. I can't imagine how the ECU would add less air when cold? More fuel always equals more speed unless you've reached the maximum limit of airflow.

He isn't going to match a Golf 1.6 though.

No, but he's hoping for at least 50mpg which I would too to be honest. My 2.0 TDI is earlier, bigger and auto and I get over 60mpg to work, half of which is the same road.

Girl at work gets around mid 20s from her RS4 during gentle driving.

Flaperon - in a Diesel fuel quality will make a massive difference to economy,

Well, yes, if you're talking about the difference between heating oil and BP Ultimate. But between the various brands and "supers"? Not a chance.

I barely get 40 out of my 2005 avant, been that way since I got it new.

Just bought a new A4 saloon 2.0tdi and that is currently getting 36.6mpg!

As for driving style - we are talking about the 'get on motorway, stick cruise on 70mph and leave it ther' style, so it's not really a factor.

Does seem a little low. I am getting 48mpg average from my 2012 120d and thats mainly crappy london city driving.

I am unsure if a 60+ is realistic....I barely get that on a 70mph motorway run and the beemer engines are a bit better than VAG usually.

Well 60mpg is what I get, I have done nothign special apart from fit Nokian tyres. And I use cruise control, which is a bit more than most people can manage it seems.

@molgrips - so based on what you've said (asuming servicing is up to date), statement of the obvious time - if the extra economy is worth it he needs to take the car to a specialist as it the mpg indeed seems a bit low

The figures I posted are from the onboard computer - i don't keep track of the tanks.

Didn't say, but mine is the 140 version, not the 170.

I am completely addicted to cruise control, and i find that going bang on 70 (by satnav - indicated 75) gives me the best balance of 'making decent progress' and fuel efficiency.

Had a bit of a play on the autoroute last year, dialling the cruise control up and down and watching the instant mpg - you can make big gains by dropping 5mph or so. 🙂

Dave

Seems like he is at the bottom end of what people get, when he should be at the top end.

Incidentally it's at the garage now having a 'health check'.

Could it be in need of being driven a bit harder for a while to clean all the soot out?

italian tuneup +1

mine gets a bit smoky if its only been used for the work run for a few weeks - bit of a booting once its up to temperature dumps a load of smoke out the back and smooths it out nicely 🙂

Dave

I had an almost identical A4, mine had 18's on it and was an s line so possibly a closer ratio box. I could get 52mog driving along twisty a roads, as long as there was no other traffic so I could go at my speed, not stop-start. However, I actually got 44mpg average over 60000 miles. I do drive hard though and cruise at 80 on the motorway, quite often gunning it on overtakes.
I have no idea where people's 60mpg stories come from, I can only assume they are quoting what they archived once, along a flat motorway with a honking tailwind sat at 55mph.
Oh, and cruise control is less efficient than normal driving as long as you know what you're doing (which I choose to ignore as time is precious to me!)

My TDI A2's economy is sensitive to a clean air filter after about 10,000 miles despite Audi saying it should be changed at 20,000 miles.

I have the 143ps engine in my Seat Exeo (Audi A4 old shape in drag!) and get the same sort of mpg you're experiencing. Will get 50mpg on a long motorway run if I keep it to 70, but as soon as you start pushing it hard it drops to low 40s. Commuting 13 miles each way a day gives me 38.

Car is a 6 speed manual with 18" wheels and I think bridgestone non eco tyres.

I have no idea where people's 60mpg stories come from, I can only assume they are quoting what they archived once, along a flat motorway with a honking tailwind sat at 55mph.

Well like I say, I've got a Passat with the older engine, Nokian energy saving tyres, new injectors and auto, and I get 62mpg almost every time I do a long motorway trip. Verified at the pump too. The M5/M6 seems to be more economical for me than the M4, I got 65mpg last time I drove back from Preston.

Oh, and cruise control is less efficient than normal driving as long as you know what you're doing

I disagree - on motorways, you can't be gathering momentum on the descents and rolling up the climbs - this is a really really bad thing to do in terms of traffic flow, you need to keep a constant speed. And if you don't use cruise you'll be slightly speeding up and correcting all the time, this is less efficient than using cruise.

I have no idea where people's 60mpg stories come from, I can only assume they are quoting what they archived once, along a flat motorway with a honking tailwind sat at 55mph.

Mine as quoted above was 3 people (and the rest full of snowboards and kit) driving from Cheltenham to Meribel and back, via the tunnel - cruise control at 70mph (speedo@75mph) on the motorways/autoroutes, and spirited enough driving up the wiggly mountain roads for me to be told off by t'missus.

Averaged over the whole return trip at 62.3mpg. I even took a picture of it because I was impressed 🙂

Dave

see, I just don't get it. I've managed a 60mpg (on the dash) once in my new Golf 2.0 143 blue motion, however day to day I get 54mpg (again, indicated). On a long, cruise control 80mph run it'll be about 53mpg and will do 55mpg if I don't use cruse over the same run.
I literally never see the figures everyone else does, I assume I've never grown up and like booting it too much!

Where you drive as much as how you drive will play a factor. Even motorway driving with lots of small braking / accelerating (Lorry's pulling out etc) will kill fuel economy.

On a long, cruise control [b]80mph run[/b] it'll be about 53mpg and will do 55mpg if I don't use cruse over the same run

There you go then... drop to 70 and your mpg will come up to the same as mine.

Dave

On a long, cruise control 80mph run it'll be about 53mpg and will do 55mpg if I don't use cruse over the same run.

If I do 80mph, I get about 53 too. Sounds good.

Try doing 70mph, you'll get much better economy. I'd have thought this was obvious 🙂

Btw, Fitting Nokian H tyres gave me about 10% better economy over Dunlop Sport.

I know, I just never seem to meet anyone who actually cruises at 70mph, any time I get in a car, it's immediately 80mph.
I think the tyres would have made quite a difference, however the car went on Saturday and I really don't expect the same from the A6 I bought to replace it. Maybe when the tyres are shot I'll have a punt so thanks for the heads up

My dad has an A6 with the same engine as my A4 and an auto box. It is a lot heavier, and he can only get about 45-50mpg out of it - and that is with the 'old-man driving' dial turned up to 11.

Dave

I used to do 80mph before I got a car that gave me detailed fuel consumption information...

Definately check cam shaft and temperature sensors. Those tend to misbehave over time and give wrong commands to ECU, temperature gauge on dashboard could show as if temperature 90c while sensors read and give different readings to ECU which in turn for example could give reading of cold temperature engine which would trick into more consumed fuel. Additive products such as Millers or Forte do help to clean system and smooth out engine running and give few mpg extra.

Then there is subject on tyres, wind speed, air temperature, etc etc.