Audi 2.5 v6 TDI mpg issues...Help

Frascano

Frascano

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Hi all,

Really need to get you all thinking because it's putting me off driving the thing

54 b6 avant 2.5 v6 180 Quattro

I'm filling up £20 and getting around 140 miles mainly town driving but driving slow, car pops up with an average of 25mpg surly something is wrong?

I've read around on forum but need more options.

MAF replacement?
Injector cleaner?
Terraclean?
New air filter?

Help

Ash
 
Many a or auto ? I have a manual a6 avant Quattro, it returns 35Mpg average according to the DIS. Remember that it's cold outside and you're hauling 1700Kg of weight and permanent 4wheel drive will impact massively your fuel economy !
 
I used to get avg 35 out of mine out here in the sticks. 140 miles to £20 is about what I'd get too. So seems about right but maybe your DIS is out of sync?

There is a way of adjusting it via VCDS, but whether it's worth it or not, I don't know.

that mileage to £20 seems ok.
 
Right I see man, I'll have to look into it but my mate gets 460 to a tank and he drives it how he wants, I get around 350 if I drive steady
 
In town I get under 20mpg, often about 15. If I drive on motorway at 70-75 I've had it up at 40mpg, 80 about 35mpg & 85 30mpg on long runs.

So yours sounds about right
 
I have had both manual and now auto.You really have to work it on tank full to tank full.DIS isnt that accurate.The manual would getover 40 on a steady run but down to 20ish in town but thats largely dependent on traffic and how you drive.The auto has been tuned right and I use V Power which also helps and that can easily get 40 on a run but again drops to near 20 round town and you cant amble in high gear which I liked to do in the manual.Dont think either ever went below 20 which might indicate something needed sorting.I have tried using tuning boxes in both and there was some improvement but had to stop because both burnt the wiring out.Also I watch the tyre pressures cos that is a big factor and lots dont bother
 
Oh right great feedback don't you think that's really bad? Haha? My mate has the same at running at 215 and he gets 35mpg driving how he wants, might get it terracleaned
 
If he gets a true 35 he cant do much in town and it might be better tuned.
 
If it's mainly town driving then you'll not see much over 25. The v6 diesel is a great motorway cruiser but not economical for pootling about. I have a manual 2.5q and it'll return 36mpg mixed driving but stop-start kills it.
 
See I would accept the 36mpg stop starting because that's good haha, motorways its shocking sitting at 63 I get 40-4mpg at a push, what can you get on motorway
 
You should get over 40 steady cruising at 80 .Thats what my auto can do on V Power tuned right and pressures right.Effectively its double the urban figure.Something on yours needs looking at.Have you made sure the brakes are fully free?When was the timing last checked?Mine was out when the belts were last changed and the retune helped a lot
 
Woop here he is :)

I do get between 400-450 to a tank, most of the time is just going to work and back with the odd poodle to a meet, my journey per day round trip is about 20 miles, 10 each way, about 10-12 total of that is dual carriage way mostly sitting at 50-70mpg, the rest is round town, i do have a little play most days too..... I would put mine down to the map and the terra clean I had done, made such a difference in every aspect of the drive :)
 
DIS is wildly inaccurate so all mine are tank-to-tank calculations but sitting at 70-75 on a flat stretch the instant mpg is about 38-40. My average is 400-440 a tank. Mind all the pumps have winter diesel just now so that usually sees you drop a couple of mpg.
 
Mike B said:
You should get over 40 steady cruising at 80 .Thats what my auto can do on V Power tuned right and pressures right.Effectively its double the urban figure.Something on yours needs looking at.Have you made sure the brakes are fully free?When was the timing last checked?Mine was out when the belts were last changed and the retune helped a lot
Click to expand...

Well tomorrow I'll be doing many motorway miles so I'll do a test at 80 for a few miles boss, what you mean by tuned? Errmm I could check, how would you check the timing?

audi-a6 said:
Woop here he is :)

I do get between 400-450 to a tank, most of the time is just going to work and back with the odd poodle to a meet, my journey per day round trip is about 20 miles, 10 each way, about 10-12 total of that is dual carriage way mostly sitting at 50-70mpg, the rest is round town, i do have a little play most days too..... I would put mine down to the map and the terra clean I had done, made such a difference in every aspect of the drive :)
Click to expand...

Haha, definitely going to take your advice brother. Map and terra needed.

frankc said:
DIS is wildly inaccurate so all mine are tank-to-tank calculations but sitting at 70-75 on a flat stretch the instant mpg is about 38-40. My average is 400-440 a tank. Mind all the pumps have winter diesel just now so that usually sees you drop a couple of mpg.
Click to expand...

Don't you think that's bad? 70mph should achieve 50+ sitting at 2k when the engine is running at full potential man?
 
I doubt anyone with a 2.5 Quattro has ever seen 50+! I was under no illusions when I bought mine that I would get mpg that high. As Chris Adams said above its 1700kg of car, permanent 4wd and let's be honest the engine design is 16 odd years old. Even the newest common rail v6 diesels are returning mpg in 40s under real-world driving conditions.

Timing belts need done at 80k mile intervals then the timing is checked using diagnostic software like VCDS and adjusted on the injection pump sprocket. If the IP timings out then it'll affect mpg and probably run rough.
 
I get that, in regards to the timing it was done by Audi and doesn't need doing for another 20k are they every 60k with Audi belts?
 
The only reliable way to check the mpg on a run would be to make it as long as poss after brimming the tank and then filling again .Having done this it is a surprise to see how much the mpg rises cos thats whatThe the car is meant for not so much a runabout.The belts should last 80k or 5yrs.Audi should know the timing routine but if has any trouble starting and/or smokes a lot this could be the timing out
 
Mike B said:
The only reliable way to check the mpg on a run would be to make it as long as poss after brimming the tank and then filling again .Having done this it is a surprise to see how much the mpg rises cos thats whatThe the car is meant for not so much a runabout.The belts should last 80k or 5yrs.Audi should know the timing routine but if has any trouble starting and/or smokes a lot this could be the timing out
Click to expand...

I'll probably do that then, I usually wait in the morning for the lights to go out on the dash to allow me to get a good start, but how do you mean it will have starting issues?
 
Before mine was retimed it was hard to start mostly when warm and smoked alot after starting.I saw mine retimed by Chri in London and he took a lot of time and trouble.Its always tempting for a mech who is in a hurry to cut corners
 
I never use the figure on DIS cos its not accurate but if you get that for most of a say a 100m round trip averaging 75 and then brim again it might give an acceptable result
 
Mike B said:
I never use the figure on DIS cos its not accurate but if you get that for most of a say a 100m round trip averaging 75 and then brim again it might give an acceptable result
Click to expand...

Okay man thanks


Still think I'm going to terraclean it
 
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