D40 Fuel Economy

[KraftyPg]

See that's the thing I just don't understand about economy. I thought I'd stuff everyone up and come in with a figure no one else could get by idling in the carpark but when I calculated the figures I couldn't manage better than 2000LPH. The figures just don't add up!!









(BTW if anyone really feels they need to explain such a ridiculous statement don't bother it's a joke!)

 

[siringo]

Well I'm going to tow the Nav behind a truck next week and see if that improves my economy, but knowing my luck I'll end up with 14's and the tyres will wear out.

 

[KraftyPg]

Tow it backwards the economy should go into the negative.

 

[siringo]

^^ No that's no good. I've only got an 80 litre tank, I'd end up creating fuel and then it would just overflow the tank. I'd need a long range tank at least, or a way of hanging out the side of the vehicle with a jerry can.

Or would that only happen if I left the rear wheels on the ground? Or if I put it in 4WD, would it make twice as much fuel??????

 

[KraftyPg]

But if you can create fuel you can sell it back to yourself at a cheaper price and therefore economy wont be such an issue.

 

[iamrichardthelionheart]

i've just dropped a recon fuel pump and new injectors in and i'm very happy to report economy is 8.02L/100km

06 STX D40 2.5D 6sp - with all the usual fruit, so it's not a light nor aerodynamic vehicle.

i'm not happy with the cost though..... no change out of $6K

the economy prior was recorded at 13+L/100 - however i found my problem was fuel leaking into the sump, so the above value isn't a true value as i found by chance, it'd would drop 3L of fuel into the sump over 4,000km.

i couldn't work out how my oil level increased, until it dawned on me there was a fuel leak - either injectors leaked or fuel pump seal failed.

 

[4BYFOR]

i've just dropped a recon fuel pump and new injectors in and i'm very happy to report economy is 8.02L/100km

06 STX D40 2.5D 6sp - with all the usual fruit, so it's not a light nor aerodynamic vehicle.

i'm not happy with the cost though..... no change out of $6K

the economy prior was recorded at 13+L/100 - however i found my problem was fuel leaking into the sump, so the above value isn't a true value as i found by chance, it'd would drop 3L of fuel into the sump over 4,000km.

i couldn't work out how my oil level increased, until it dawned on me there was a fuel leak - either injectors leaked or fuel pump seal failed.

Damn man thats costly..

 

[doog]

mine has now done 11000 klm's and it sits at 8.5lt/100, before the service at 10k it would get down to 8.2 on occasions.

mix of suburban/city driving some cruise control & i dont like Prados and hiluxes beating me away at lights. so they usually don't.

 

[Passage GT]

are you driving on 2 cylinders! forgive me but that seems so out there, if what you are getting is correct then maybe mine needs to get looked at. the best mine will do is 11-12l/100

to be honest mate i'm pretty bloody happy with it, one thing that did make a noticeable difference was sitting in 5th gear instead of 6th, my initial instinct was to stay in 6th because the revs sat lower and i could still accelerate without it struggling for hills etc.
however switching to 5th put it right in the sweet spot, barely any throttle on and you'd just breath on it to power over the crests and hills etc.
despite sitting on a higher rpm the less throttle use made a dramatic difference in economy.
I'm thinking of getting an aftermarket exhaust for it down the track and see if that improves it even more, currently the only mods engine wise is an EGR block.
i've got a couple pics of my scanguage from through the day.

 

[nathand22]

Personally i have found the scanguage ll to be so inaccurate i stopped even looking at the fuel info and just add up my fuel the old proven way every time i fill up.
I found i could make the scanguage range from 4LPH and up to 32LPH if i wanted to and it would depend on how long the trip was and what sort of terrain i was on, and what speed i reached.
for eg if i did a short 10km drive up to the next town i could get figures of around 4LPH but do a trip on the freeway and it was an entire different story, then compare actual figures over the entire tank with my own and it was always out by at least 2Lph.
So know i dont even bother to type in how many litres i put in at each fill, i just use it for water temp, volts, intake air temp, and speedo reference but even that is out when i run the bigger tyres.

 

[flashum1]

08 diesel manual, exhaust, snorkel, 265 mud terrains, 3"lift, steel bullbar, wouldn't be far off max weight pulling 2.5 tonne 23 ft coromal returned 16.8 per 100 last 3 tanks from bega to Evans head. Got dom3 sitting in caravan waiting for free day to fit. Hoping for 15 or better after! Worst was 20lt p/100 but no idea why it's gotten better.

 

[big zetor]

different fuel maybe! mine user's more when i run bp through it, nI use shell most of the time.

 

[flashum1]

Don't think I've ever tried shell, run bp most the time cause I know it's good. Used to run caltex allot too as its usually a couple of cents a litre cheaper until I got a bad batch a few weeks back, consumption didn't change too much, was way down on power pulling van up hills. Really gotta make time for Dom3 real soon!

 

[Passage GT]

Personally i have found the scanguage ll to be so inaccurate i stopped even looking at the fuel info and just add up my fuel the old proven way every time i fill up.
I found i could make the scanguage range from 4LPH and up to 32LPH if i wanted to and it would depend on how long the trip was and what sort of terrain i was on, and what speed i reached.
for eg if i did a short 10km drive up to the next town i could get figures of around 4LPH but do a trip on the freeway and it was an entire different story, then compare actual figures over the entire tank with my own and it was always out by at least 2Lph.
So know i dont even bother to type in how many litres i put in at each fill, i just use it for water temp, volts, intake air temp, and speedo reference but even that is out when i run the bigger tyres.

that's a fair call, i did a bit over 200km for the day and it hadn't quite reached the 3/4 mark on the fuel guage.

 

[KraftyPg]

I'd suggest if SG isn't accurate send it back and get it calibrated. Over an entire tank mine is always within +/- 0.2LPH to calculated figures, the only time it wasn't accurate was the time I forgot to make the tank 80l after a reset and I was getting readings of 255lph while cruising at 90kph on the freeway.

Live figures (which aren't actually live) will vary and can vary dramatically depending on many different factors and like any car computer such figures should only be used as a guide but the entire tank figure should be almost spot.

 

[siringo]

Yesterday, going off the fuel giage in the dash, I got approx. 137km's for a 1/4 tank. Was doing about 105 up and down hills with a gentle right foot.

Had torque running this morning while driving this morning and noticed that I may be able to get better economy driving in 5th gear. Torque said that the litres/100 k's reading may be slightly better in 5th than 6th.

I'm of the conclusion that there's a big bug in the ECU software in these Thai King Cab's of my version of them anyway. Between crap economy and that surge problem in 4th low.

 

[mick087]

siringo i would have to second you on the bad economy with the thai king cabs.

I have a 2" lift and running 265/75 BFG KM2's, bulbar and snorkel and I consistently get 15L/100KM. It doesn't seem to matter how I drive it, it just seems to stay the same. Admittedly on a decent highway run it come back to 12.5L-13L/100KM but still miles off the 9's and 10's a lot of people seem to be reporting.

Cheers, Mick.

 

[KraftyPg]

Given that it's not all Thai built utes that have the issue and it's more than likely that all Thai ECU's if not all ECU's come from the same factory I would reckon the main error is in the ute and it's build.

I doubt it's the entire story but the way the air would flow in and around a tray compared to the tub would have to make a difference. Going by pics on the net there is a fair bit of air flow possible under the tray and across the chassis which with a tub wouldn't be as great and the tray is wider than the tub.

There is no doubt more to it than just one factor especially given that not every KC suffers the same problem but given how the ECU's operate I'd still suggest it's less about the ECU and more about the vehicle itself.

 

[siringo]

Yeah maybe???

One thing I have noticed, and I won't be surprised if I'm totally wrong, the King cab's with onboard computers (scrambling for the correct lingo here), ones with buttons on the LHS side of the steering wheel seem to get better fuel economy. Mine doesn't have any inside computer gizmo's, just cruise control. I wonder if this means the ECU is different???

Watching Torque's litres/100 km realtime output was interesting. It altered even when the vehicle was buffeted by wind, it seems incredibly sensitive.

If you take your foot off completely, it reports 0L/100km's. I took off from a dead stop up hill and it read 78.3L/100 km's.

Torque currently says I'm getting 7.6L/100 k's, but I'm almost dry and I think I've just gone over 500k's on a dripping out the top filled tank.

 

[Passage GT]

it certainly made a huge difference in my car sitting in 5th instead of 6th, though this was at around 80-90kph, i think it's because in 5th you have almost no throttle opening, even though it's revving higher, in 6th you've got your foot further down and the engine is under more load.
i think in hilly conditions at slightly less than highway speeds driving in 5th may be more beneficial to economy, i think obviously on flat surfaces at open highway speeds and more the advantage of 6th comes into play.
i might experiment a bit with it next time i drive to Perth, she was pretty heavy on fuel towing a loaded up glass boat, not huge, about 24 foot i think but was loaded with gear for my old man who was moving back down south, in hindsight i'm thinking i may have used less fuel sitting on 100kph in 5th.