Thread: The D2a Diesel with never changing fuel economy

Do you lose weight each time you work on the car?

i think your miss reading numbers it should change but not that much,

twr7cx

I think what is more likly is that as you do a mod and notice an improvement you quickly adapt your driving style as you get used to the increase in performance and then start driving to that increase. in other words, you're putting the welly in.

Just my thoughts.

Nino.

What Nino said.

Same phenomenon here. I you want some economy back put a donaldson pre cleaner on.

You will hear the loud sucking noise when the cyclone builds up on the fujita scale & back the foot off accordingly, will save heaps on fuel.

Originally Posted by landy

I think what is more likly is that as you do a mod and notice an improvement you quickly adapt your driving style as you get used to the increase in performance and then start driving to that increase. in other words, you're putting the welly in.

I'm assuming that by welly, that's some UK reference to a boot, so your saying that I start booting around. No. My vehicle normally get 450km out of a tank, almost religiously for the last 11 months that I have owned it. I flog the truck, it's either on the accelerator or brake pedal, but not inbetween, when unloaded or otherwise it's towing my boat.

After doing a mod like a larger intercooler or winding up the boost, I don't suddenly stop booting it because it's now got more power - the opposite is more accurate as (as who adds more power not to then use it?). However, after these changes I usually get 550 to 650km per tank for the next tank with no change in driving style or routes taken, then straight back to the old 450km for the following tanks. Also of note is that the black overfueling smoke goes away during this high milage tank, and returns afterwards indicating that the engine is running from lean to rich.

This has occurred 4 times now.

So aside from unbased opinions on my driving style, that I don't care much for, does anyone have any actual knowledge on the ECU setup that they can share?

Originally Posted by twr7cx

I'm assuming that by welly, that's some UK reference to a boot, so your saying that I start booting around. No. My vehicle normally get 450km out of a tank, almost religiously for the last 11 months that I have owned it. I flog the truck, it's either on the accelerator or brake pedal, but not inbetween, when unloaded or otherwise it's towing my boat.

After doing a mod like a larger intercooler or winding up the boost, I don't suddenly stop booting it because it's now got more power - the opposite is more accurate as (as who adds more power not to then use it?). However, after these changes I usually get 550 to 650km per tank for the next tank with no change in driving style or routes taken, then straight back to the old 450km for the following tanks. Also of note is that the black overfueling smoke goes away during this high milage tank, and returns afterwards indicating that the engine is running from lean to rich.

This has occurred 4 times now.

So aside from unbased opinions on my driving style, that I don't care much for, does anyone have any actual knowledge on the ECU setup that they can share?

There is no mechanism for the td5 to alter fueling settings autonomously. It responds to sensor inputs, so the only way you'd get the kind of your describing would be for a sensor to be switching between two distinct states in response to some action that has been common to all your mods.

If I recall right your D2 had fuel consumption issues when you purchased it . I seem to remember you posting that one of the mods you did had fixed the issue but if you are saying consumption resets after a tank I'd have to assume the fix was temporary?

Are you disconnecting the battery when you do the mods that result in the improvement?


Cheers
Paul

Sounds like your may be disconnecting battery between mods...

Is it auto? Have you reset transmission adaptations?

Skuilnaam

Originally Posted by OffTrack

If I recall right your D2 had fuel consumption issues when you purchased it .

Yes, when I purchased my D2a it had multiple issues including bad fuel consumption (between 400 to 450km a tank) and constantly cutting out (overboost issue). Fitting a TD5 Alive/Alive Tuning Turbo Booster Box and uprated MAF sensor solved the overboost issue and caused an increase in fuel economy to what it is now - a fairly consist 450km per tank (bearing in mind that it is now running 3" larger tyres and has a 4" suspension lift).

Originally Posted by OffTrack

I seem to remember you posting that one of the mods you did had fixed the issue but if you are saying consumption resets after a tank I'd have to assume the fix was temporary?

Yes, the fix was temporary. When I rebuilt my fuel pressure regulator I got 650km out of the next tank - no difference in vehicle power or my driving style. Afterwards it fell back down to 450km per tank.

This also happened when I fitted a larger intercooler.

Also when I increased the boost pressure.

And my VNT and Ashcrofts Torque Converter have now arrived so I will be interested to see what effect these has.

Originally Posted by OffTrack

Are you disconnecting the battery when you do the mods that result in the improvement?

Originally Posted by skuilnaam

Sounds like your may be disconnecting battery between mods...

No, I avoid disconnecting the battery as the alarm goes nuts when I reconnect it, so generally I work with the battery in place and connected unless it needs to be removed.

Out of interest, what difference would/could disconnecting the battery make?

Originally Posted by skuilnaam

Is it auto?

Yes.

Originally Posted by skuilnaam

Have you reset transmission adaptations?

No, got any more details on this?


My other vehicle is a Ford Falcon ute - hand built 5.6L stroker 342ci Windsor V8 - it's achieving the same fuel economy as the D2a, and it's not driven easy either...