Q5 awful mpg

[Spaced69]

Where do i start...lol
Bought a q5 2.0 tdi s-line s tronic 160k full service history. 1st had cambelt and full service done for peace of mind...noticed was putting twice as much fuel as my old a6 2.7tdi...had remap done...was very responsive but fuel consumprion still as bad...took to garage...so far had dpf knocked through and had economy map put on with dpf and egr mapped out...mpg was just as bad...went back to garage..injectors tested...marginal..but paid for new nozzles ro be fitted..mechanic rekons mpg better...picked up car as had to drive london for new year...reset mpg as hit m40...over the 130 miles with no traffic and steady 75mph the avg mpg was a terrible 34mpg
What else could be wrong as fed up chuckin money at a car that should have fairly good mpg

[Renars]

Where do i start...lol
Bought a q5 2.0 tdi s-line s tronic 160k full service history. 1st had cambelt and full service done for peace of mind...noticed was putting twice as much fuel as my old a6 2.7tdi...had remap done...was very responsive but fuel consumprion still as bad...took to garage...so far had dpf knocked through and had economy map put on with dpf and egr mapped out...mpg was just as bad...went back to garage..injectors tested...marginal..but paid for new nozzles ro be fitted..mechanic rekons mpg better...picked up car as had to drive london for new year...reset mpg as hit m40...over the 130 miles with no traffic and steady 75mph the avg mpg was a terrible 34mpg
What else could be wrong as fed up chuckin money at a car that should have fairly good mpg

Well its bit too much, 40 - 45 should be more realistic.
What is your long term average ?

[Spaced69]

On daily basis avg 20mpg

[Renars]

If there is no massive smoke coming from exhaust I say fuel is leaking somewhere.

[Pev]

That is very poor mpg. Barring a fuel leak, have you renewed the air filter & cleaned the MAF sensor with electrical contact cleaner? If that improves your mpg then I would buy a K&N lifetime air filter

I just sold a VW Bora that I had from new for 15 yrs and fastidiously maintained it myself. I had it re-mapped to 160bhp soon after I bought it and it was regularly returning 56mpg (full tank to full tank) with a best of mid 67 mpg if I cruised at 60mph on the motorway.

[Gazwould]

K&N , lol . OE is best .

https://www.honestjohn.co.uk/realmpg/audi/q5-2008

[Pev]

OE is perhaps only better if you change your car frequently. I have always put K&N filters in all my cars but then I keep my cars for at least 10 yrs, the longest being 23 yrs! The Bora I mentioned in my last post was on 173,000 miles when I sold it and averaged 56 mpg from new (that is tank to tank, not off the digital readout, and recorded every time) and really flew when I needed it to.
I was a professional diesel engineer for 15 yrs and my cars only go into a local garage when I need work doing that necessitates a garage lift.
It's all down to how well you service, drive and generally maintain your car.

[Gazwould]

You don't have to tell me .

Remaped 1.9 130PD , almost 180 bhp , 507.00 LongLife oil changes every 6 months with as little as 1,300 miles between.
182k now .

The K&N requires cleaning , offers no performance advantage and won't provide this much surface area filtration .

https://i.imgur.com/jIVoXwY.png


Any 2 Stroke use ?

[Pev]

Very good, you must look after your cars too:) I've seen a similar photo comparing the surface area of Mann filters to many others so now always tend to buy Mann. I buy my oil and filters in bulk and service my cars after 2,500 miles from new and then every 7,500miles.

I'll still stick with the K&N filters though and clean and re-oil every 12k. Incidentally I fit coolant pre-heaters on all my cars and rarely start them cold unless I am away from home or have to go out unexpectedly.

Incidentally when I sold my Bora it was still on the original clutch and showing no signs of slipping unless I inadvertently gunned it from low revs in a high gear which it would do after I had it re-mapped.

I did put in 50ml of low ash 2 stroke oil with every tank for a short while until I looked further into it and then stopped doing that. I have though for the last 10 yrs put in 60ml of Millers Diesel power (buying a 5 litre can) every time I fill up.

I use the Fuelio app to accurately record my mpg.

[Gazwould]

50ml to a tank isn't enough , why we're you put off ?

Millers works as it has 2-EHN .

[Pev]

My mistake I meant to say 200ml of 2 stroke. I bought a dozen small plastic 250ml bottles which I put in 200ml of 2 stroke and 50ml of Millers. I added that to every full tank of the 2 diesel cars I was running at the time. I did that for about 18 months.
Then another engineer friend of mine, who I told about adding 2 stoke oil, contacted Shell UK and they sent him a detailed reply advising against doing so which he sent to me but I didn't keep. I also read on another forum that because it has zinc in it it can eventually block the injectors. So now I just add Millers. I have the 70 litre fuel tank on my Q5 so add 70ml of Millers every time.

[Gazwould]

Biased reply !

JASO B or C ?

[Spaced69]

Just an update
Just wasted another £300 having a dieselgate rollback and a remap
Car is exactly the same...on motorway at 70 can just squeeze 40mpg on straight level part
Around town druving like miss daisy it avg 19mpg
So tired of this car and about to sell the dam thing
So wish i had my 2.7tdi a6 back
Using twice as much fuel in this q5