D40 Fuel Economy

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Hi Guys, just filled up I am getting 11.7ltr/100km
will this improve as the car has only done 2060km
thanks in advance


Seems high, I was getting under 9 when I first bought it (March 2014) and now consistently under 8.2 (currently 7.8 out of this tank).
 
I have a 2012 King Cab automatic. I reset the trip meter at every refill to see how it's going with fuel consumption, just in case a miracle happens. Latest fill, after about 60 or 70 km suburban, the rest open highway at the 110 speed limit, about 15l/100km. Sometimes on a pure highway run it may go as low as 13.

Tow anything decent and I'm looking at low 20's. Put a load of wood or concrete slabs in the back and it is around 18.

It was worse before I removed the DPF, blanked the EGR and fitted a snorkel. It was then 16 on pure highway runs, approaching 20 loaded and 24 towing. Dealer has checked it and says consumption is normal.
 
I never trust the trip computer and always did my fuel consumption figures with both my 2010 ST and my 2012 ST at the end of every tank MANUALLY.

I could get the computer to say what ever i wanted it to depending on when i reset it and how much foot i was putting into it. I once drove to the next town and back on semi rural roads and it came up saying i was using 5LPH!! lol what a load of BS because when you go back to the pump and fill it up then do the figures manually it is way off.

I never saw below 9.5LPH ever and the one or two times i did was after driving for the entire tank not letting it rev over 2200rpm and getting to those revs gently ect, it was with out a doubt the most painful driving.

Normal day to day which inc lots of freeway i would get around 11.5LPH - 12.5LPH after an entire tank.

Maybe it was just the way i drove or the set up i had, but those figures were pretty much consistent all the way through the mods and tyre changes ect in both models.
I had a set of free way stockers and the fuel would change by around .5-1LPH

I would love to see if those 7LPH figures people say they are getting are added up after an entire tank of fuel manually or are just quoted off the trip computer, i would also love to see how you have to drive in order to get such wonderful figures out of a brick on wheels.
 
I have a 2012 King Cab automatic. I reset the trip meter at every refill to see how it's going with fuel consumption, just in case a miracle happens. Latest fill, after about 60 or 70 km suburban, the rest open highway at the 110 speed limit, about 15l/100km. Sometimes on a pure highway run it may go as low as 13.

Tow anything decent and I'm looking at low 20's. Put a load of wood or concrete slabs in the back and it is around 18.

It was worse before I removed the DPF, blanked the EGR and fitted a snorkel. It was then 16 on pure highway runs, approaching 20 loaded and 24 towing. Dealer has checked it and says consumption is normal.

First, welcome to the forum!

I've never heard of a 2012 KC with a DPF, that's new - the last model I've heard of with a DPF was the early 2010 STX dual cab auto (the last of the Spanish 126kW models). If yours had a DPF, it would be interesting to see if auggie (a user here on this forum) could organise some sensor replacements for you to stop the car from doing regens.

In any case, with or without a DPF, the king cabs were always a little thirsty. Rumour has it that there's a software upgrade for the ECM to alleviate this, but getting the Nissan internal reference so that you can say to your dealer "Look up TSB number x" to get the fix in your car isn't as easy as it might seem.
 
the trip meter is an educated guess from the cars computer, they aren't all that accurate when it comes to fuel economy, they will be close but to get an accurate reading you need to do it the old fashioned way
cheers
 
the trip meter is an educated guess from the cars computer, they aren't all that accurate when it comes to fuel economy, they will be close but to get an accurate reading you need to do it the old fashioned way
cheers

I thought the distance shown on the trip meter would be driven by the same source as the odometer and not be a number guessed by the ECU. Seems incongruous to me to have some sort of extra algorithm code in the ECU to calculate distance by other means. My trip meter distance seems to match the distance on the odometer, so is the odometer just an educated guess of distance from the ECU too?

I am interested in knowing the old fashioned method of measuring distance if the odometer and associated trip meters are just a guess of distance?
 
sorry I meant to type
the "fuel consumption" is an educated guess, not trip meter, my apoligies
it has been proven many times (including on "mythbusters") that there are way too many variables for an accurate reading from your trip meter (regarding fuel consumption, not distance)
windows down ,windows up, ac on or off battery fully charged or not (alt load will affect economy)
 
First, welcome to the forum!

I've never heard of a 2012 KC with a DPF, that's new - the last model I've heard of with a DPF was the early 2010 STX dual cab auto (the last of the Spanish 126kW models). If yours had a DPF, it would be interesting to see if auggie (a user here on this forum) could organise some sensor replacements for you to stop the car from doing regens.

In any case, with or without a DPF, the king cabs were always a little thirsty. Rumour has it that there's a software upgrade for the ECM to alleviate this, but getting the Nissan internal reference so that you can say to your dealer "Look up TSB number x" to get the fix in your car isn't as easy as it might seem.

I ordered it from new and I didn't know about the DPF until I took delivery. I also didn't know I was getting the 126kW spec engine either. Salesman showed me a dual cab and said the king cab is exactly the same except for the cab configuration. Boy, was I mislead.

Apparently it seems it was only the auto king cabs that got the DPF, and not the manual version.

I've removed the DPF and I've seen auggie, who couldn't get into my ECU to turn off regens or do a retune. Something quirky about my ECU apparently.
 
sorry I meant to type
the "fuel consumption" is an educated guess, not trip meter, my apoligies
it has been proven many times (including on "mythbusters") that there are way too many variables for an accurate reading from your trip meter (regarding fuel consumption, not distance)
windows down ,windows up, ac on or off battery fully charged or not (alt load will affect economy)

I just use basic arithmetic from the distance on the tripmeter and fuel volume indicated on thepump to fill the tank right up. I just can't see how windows down or up or whether or not the battery is fully charged can affect the arithmetic and cause the resultant economy figure to be inaccurate.
 
It's a well known fact that driving with windows down increases the wind dispersion and interferes with what is already a 2tonne bricks limited aerodynamics. When the alternator is working hard it's dragging power as does the air conditioning "about 4 h/p", that is what Sparra04 was referring to. Have you a GPS? fill your tank to the top of the filler drive 200kms then refill and check how many ltrs you used. That's the best you can do mate if your arithmetic is not working for you.
Cheers
 
It's a well known fact that driving with windows down increases the wind dispersion and interferes with what is already a 2tonne bricks limited aerodynamics. When the alternator is working hard it's dragging power as does the air conditioning "about 4 h/p", that is what Sparra04 was referring to. Have you a GPS? fill your tank to the top of the filler drive 200kms then refill and check how many ltrs you used. That's the best you can do mate if your arithmetic is not working for you.
Cheers

I thought to calculate fuel consumption all you had to do was work out the number of litres used over a 100km, and I don't recall seeing it expressed in any other way for many years here in Australia. I reckon my tripmeter/odometer is accurate enough for the distance and the diesel bowser accurate enough for the amount of fuel used.

I just can't understand people saying this is the wrong way to do it and there are more variables to take into account in the initial calculation.
 
All I am trying to say mate is your cars fuel calculations wont be as accurate as a mechanical measurement
even having worn tyres WILL affect the outcome using your cars calculations, do you still run factory rubber?
how accurate do you need to be
 
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I thought to calculate fuel consumption all you had to do was work out the number of litres used over a 100km, and I don't recall seeing it expressed in any other way for many years here in Australia. I reckon my tripmeter/odometer is accurate enough for the distance and the diesel bowser accurate enough for the amount of fuel used.

I just can't understand people saying this is the wrong way to do it and there are more variables to take into account in the initial calculation.

You are a very confused person, I don't think anyone can give you the answer you seek or will be satisfied with. Good luck with your future endeavours.
 
I thought to calculate fuel consumption all you had to do was work out the number of litres used over a 100km, and I don't recall seeing it expressed in any other way for many years here in Australia. I reckon my tripmeter/odometer is accurate enough for the distance and the diesel bowser accurate enough for the amount of fuel used.

I just can't understand people saying this is the wrong way to do it and there are more variables to take into account in the initial calculation.

You are correct and I think that people talking about related but different things using similar terminology is making it difficult to follow things here.

By far the most reliable method - and one many of us here use - is the trip meter reset at tank fill, then divide the litres filled by the hundreds of km travelled (including decimals). Example: 45 litres to travel 425km = 45/4.25 = 10.588 LPHK.

Some of the conversation relates to how the car does its calculation. It knows how much fuel you're currently using (because it's opening the injectors at a particular rail pressure and engine RPM) so it has a fair idea of how many more km you could do based on the amount of fuel left in your tank.

Obviously many factors can influence this. Increasing or decreasing the drag on the car is in the mix as well and I distinctly remember being able to get my 1962 VW Beetle from its max speed of 70km/h up to a massive 80km/h if I wound up the windows. Putting a rail pressure chip will confuse the hell out of the ECU, because it is thinking the rail pressure is at X kPa but because the chip is modifying the signal, it's actually using more.

So you ARE right - and we DO measure our fuel usage in that fashion.
 
when I am in 2nd gear at 5500 rpm my instant fuel reads 87 litres per 100ks
there's no way that's accurate
 
Navaras have trip computers? When did this happen?

You are correct and I think that people talking about related but different things using similar terminology is making it difficult to follow things here.

By far the most reliable method - and one many of us here use - is the trip meter reset at tank fill, then divide the litres filled by the hundreds of km travelled (including decimals). Example: 45 litres to travel 425km = 45/4.25 = 10.588 LPHK.

Some of the conversation relates to how the car does its calculation. It knows how much fuel you're currently using (because it's opening the injectors at a particular rail pressure and engine RPM) so it has a fair idea of how many more km you could do based on the amount of fuel left in your tank.

Obviously many factors can influence this. Increasing or decreasing the drag on the car is in the mix as well and I distinctly remember being able to get my 1962 VW Beetle from its max speed of 70km/h up to a massive 80km/h if I wound up the windows. Putting a rail pressure chip will confuse the hell out of the ECU, because it is thinking the rail pressure is at X kPa but because the chip is modifying the signal, it's actually using more.

So you ARE right - and we DO measure our fuel usage in that fashion.

Cheers for some enlightenment. Mine doesn't have a display to tell me what my vehicle's ECU is calculating. The salesman told me when I ordered mine it would be exactly the same as the twin cab display and demo models on the car lot, except it would be a king cab.

So I just assumed, because I have a late 2012 model that cost north of $50k new and it doesn't have a trip computer, that no 2.5 litre models had them, so it didn't occur to me that someone would assume I meant trip computer when I said trip meter.
 
when I am in 2nd gear at 5500 rpm my instant fuel reads 87 litres per 100ks
there's no way that's accurate

I bet if you drive for a 100km in 2nd gear at 5500rpm you'd probably get close! 2nd is pretty low (relative to top gear), I watch mine pulling over 50 litres per hour when I'm taking off up a hill with the van on the back and I've no doubt she'd drink the tank dry if I had to keep the throttle - and revs - at those levels.
 

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