The D2a Diesel with never changing fuel economy

So I have owned my D2a for over a year now (for those not familiar with the vehicle, I purchased it from Phil/snowwhite in Sydney). During this time the fuel economy has not changed since the day I got it - I get almost exactly 450km per tank (except two tanks in a year that managed to achieve higher) - the average fuel consumption is 15.5L per 100km.

Now during this time I have done the following additional modifications, all of which you would think would effect the fuel economy in some way:
32" tyres
Roof rack
4" suspension lift
VNT
AliveTuning intercooler
Boost adjust
New TD5Inside tune
Winch and lights fitted to the front bar

Not one of these modifications has effected the fuel economy up or down!
Even Jose from TD5Inside recently redid the tune, it was on a very aggressive tune which was resulting in the vehicle running rich (thick black smoke out the back at wide open throttle and very high exhaust gas temperatures on hills according to the MadMan EMS) - the new tune has no black smoke out the back (visible from the rear view mirror) and the exhaust gas temperatures are much lower all around - indicating it is running a lot leaner - despite this, no change to fuel economy.

I've tried different service stations - BP, United, Caltex, Shell, etc. all through NSW, Victoria and Tasmania, with no change in fuel economy.

Recently I towed my boat (Haynes Signature 520) for 400km - exactly the same fuel economy as when I drive around with only me in the vehicle!

It seems I just have an odd vehicle.

Jose from TD5Inside was kind enough to redo the tune from scratch to suit the current modified set up at no additional cost (big thanks and recommendation to him).

I have run the vehicle now for a full tank of fuel. It was on a very aggressive tune which was resulting in the vehicle running rich (thick black smoke out the back at wide open throttle and very high exhaust gas temperatures on hills according to the MadMan EMS) - the new tune has no black smoke out the back (visible from the rear view mirror) and the exhaust gas temperatures are much lower all around - indicating it is running a lot leaner - despite this, no change to fuel economy.

He has asked me to:

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Can you plug your nanocom, make some read fuelling files and send it to me, so that I can see if i can find what the problem is....

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Which is exactly what OffTrack recommended a while ago (that I still haven't done).

I need to pull the Nanocom out this weekend and work out how to recode this information (if anyone wants to provide a brief description that would be very much appreciated).

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Originally Posted by twr7cx

So I have owned my D2a for over a year now (for those not familiar with the vehicle, I purchased it from Phil/snowwhite in Sydney).

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haha, snowwhite, he'll love that! :D

as to the economy that does seem odd, did the auto ever get rebuilt and could that be affecting the ecomony due to incorrect shift points?.
maybe install a sail, that might bring some gains. :angel:

That is a lot of fuel! Disco's should be economical. At a guess it is using too much which is why it doesn't change when you tow.
Have the injector pump and injectors ever been done?

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Originally Posted by The Angry Chook

That is a lot of fuel! Disco's should be economical. At a guess it is using too much which is why it doesn't change when you tow.
Have the injector pump and injectors ever been done?

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Td5s don't have an injector pump- only an in tank pump and unit injectors.

Any Nannocom reported errors?

Hi,

As I already told you, Phill request us a super mega super extra mega powerful map...and that´s what we did eheh :)
He had some flat spots some other remaps and we managed to correct them!

The new map we made for you is less powerfull ...

Get some fuelling readings with the nanocom and send them to me... I will try to see If anything strange pop up and help you out with this!

Just pop-up in to my head while reading your other post....could'nt this be a problem with the speedo??? I remember that a costumer of us had a similar problem (he changed tyre size) and we had to make speed readings from a gps and a terratrip... the speedo error was enourmous!!!! Anyway, just a tought!!

Regards

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Originally Posted by td5inside

Phill request us a super mega super extra mega powerful map...and that´s what we did eheh :)

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That doesn't sound like the Phil I know. He's normally very restrained & almost conservative when it comes to his cars.





:angel::angel:

I´ve answerd you on the other post regarding this subject, but....could'nt this be a problem with the speedo??? I remember that a costumer of us had a similar problem (he changed tyre size) and we had to make speed readings from a gps and a terratrip... the speedo error was enourmous!!!!

What if, your speedo is reading 100km and In fact you are running 120 or 130 km?!!!

Regards!

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Originally Posted by Scouse

That doesn't sound like the Phil I know. He's normally very restrained & almost conservative when it comes to his cars.

:angel::angel:

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In fact, Phil´s map was a big challenge to us, because he had experienced other maps and had some problems with them... When I say big extra power, of course it was request/made with reliability !!

We work together and made - if I remember - 2 or 3 versions of the map, with Phill always giving us his feedback and also some fuel readings...this was very important and very helpfull from him!
We managed to sort out a good powerful and reliable map...

Regards

if we were to blame the map, my opening guess would be the injection is retarded so your not getting everything you could out of it.

more realistically tho if everything seems to be performing normally Id start by looking at the exhaust, very similar symptoms occur if


you have excessive restriction in the exhaust
if the wastegate is opening to agressively or not closing off correctly.
the EGR butterfly is not opening all the way.

if its an auto you might also be getting some flare on TC or in the clutch packs, ID start by following the auto diagnostics drive test after doing a stall test to see whats what in that department. It doesnt sound like an auto problem if its towing ok but thats likely to be the most expensive bit to fix if its the problem so lets eliminate that first.