Hi all. Thanks for the opportunity to join the forum. I have a question regarding the accuracy of the fuel Guage in the new Navara. What i have found is that the fuel light is on and when i re fuel it takes just over 50 liters. Does this affect the liter per hundred value due to the 30 liters still in reserve in the tank. At the moment i cannot get better than 11 per 100
Fuel guage/ Tank level
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In the older (2013 and older) models at least (and perhaps some newer ones), the fuel gauge is a very simple 12V supplied to a variable resistor on a float in the tank and the resulting voltage is used to deflect the needle. It doesn't affect fuel consumption figures or calculations.
The most effective way to calculate fuel economy is to use one of your trip meters and reset it each time you fill the tank. Don't partial fill, write the km travelled on the receipt and then calculate the LPHK easily. Reset the trip meter before driving away.
The calculation is then quite simple (it looks complicated at first glance).
litres bought divided by (distance divided by 100) = x LPHK
Let's say you bought 43.50 litres and travelled 501.8km (I'm getting this off one of my fuel receipts for one of the cars here). The math looks like this:
43.5 / 5.018 = 8.668 LPHK
The easiest way to remember it is to divide the litres by the km and just shift the decimal point two places to the left.
Will a newer car (using a CAN-based fuel gauge) have problems with it? I doubt it. They seem to be calculating the fuel consumed (and thus the fuel usage and then estimate distance to empty) based on their fuel map (injector duration/pulses and fuel pressure produces a specific amount of fuel) so at a given RPM you can accurately predict how much fuel is being delivered to the engine.
In the older (2013 and older) models at least (and perhaps some newer ones), the fuel gauge is a very simple 12V supplied to a variable resistor on a float in the tank and the resulting voltage is used to deflect the needle. It doesn't affect fuel consumption figures or calculations.
The most effective way to calculate fuel economy is to use one of your trip meters and reset it each time you fill the tank. Don't partial fill, write the km travelled on the receipt and then calculate the LPHK easily. Reset the trip meter before driving away.
The calculation is then quite simple (it looks complicated at first glance).
litres bought divided by (distance divided by 100) = x LPHK
Let's say you bought 43.50 litres and travelled 501.8km (I'm getting this off one of my fuel receipts for one of the cars here). The math looks like this:
43.5 / 5.018 = 8.668 LPHK
The easiest way to remember it is to divide the litres by the km and just shift the decimal point two places to the left.
Will a newer car (using a CAN-based fuel gauge) have problems with it? I doubt it. They seem to be calculating the fuel consumed (and thus the fuel usage and then estimate distance to empty) based on their fuel map (injector duration/pulses and fuel pressure produces a specific amount of fuel) so at a given RPM you can accurately predict how much fuel is being delivered to the engine.
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Tony, if those numbers are from your D40 I'm going to cry haha
No, my Nav pulls more like about 12.5LPHK these days. I'm going to take the rack off the roof and see if that improves things (it should).
12.5 towing that van?? my stx550 gets 10 lphk around town, and about 15 lphk towing a 21ft6inch 3tonne van
That's on its own. Towing the van is a whole new realm of pain and bank loans.
15.5LPHK on level(ish) ground not exceeding 80km/h
18LPHK on level(ish) ground up to 100km/h
21LPHK mixed with moderate hills
what model do you have?
most utes typically 70 litre tank, but i see some have 80 litre tank.
fuel light on at 50 litres is about right for a 70 litre tank. keep in mind you never want to run out of fuel with a diesel and the diesel is used to cool the injection system. the D40 had issues with running out of fuel when at steep angles and 1/4 tank of fuel left, i think there was a fix for that. my guess is they now allow more reserve fuel to help stop that happening.
as far as fuel usage goes, the gauge measures what gets injected into the engine. the mileage remaining info is a guesstimate.
what your fuel economy is depends greatly on how you drive and what your load is.
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2007 D40 Navara Diesel Manual.
I've just come back from a roadtrip around outback NSW, towing a Jayco Lark Pop-top caravan, weighing about 1100kg + luggage etc. No roof racks or additions to the van.
I tracked fuel usage using the FuelMap App. Does same calcs as Tony says above.
I had 3 x road types:
1. sealed roads, small hills & dips ... 6th gear, back into 5th or 4th to get up etc.
2. sealed roads, dead flat for as far as the eye can see
3. unsealed dirt tracks, 100kms of travelling 60km/hr, generally flat terrain
Overall I averaged 12 litres/100 km.
On the open road, highways, I mixed it between sitting at 95km/hr in 6th gear, at just under 2000rpm. Could increase it to 2200rpm at 100-105km/hr and still maintain about 12l/100kms.
Undulating sealed roads, where I'd have to drop down to 4th or 5th to climb an incline, saw the fuel consumption rise to the 13l/100kms.
The dirt roads, sitting in 4th gear, at 2100rpm, and dropping down to 3rd/2nd gear for those wretched cattle grids, up down, up down, and it'd then average 13-13.5l/100kms. Occassionally I'd get it up to 5th gear, 70km/hr, 1600rpmish ... but if I had to slow down, it'd be drop back into 4th.
Now I am home, and have the App, i'll start testing normal regional Vic country driving, into town and back and see how she goes without any towing load.
I've just come back from a roadtrip around outback NSW, towing a Jayco Lark Pop-top caravan, weighing about 1100kg + luggage etc. No roof racks or additions to the van.
I tracked fuel usage using the FuelMap App. Does same calcs as Tony says above.
I had 3 x road types:
1. sealed roads, small hills & dips ... 6th gear, back into 5th or 4th to get up etc.
2. sealed roads, dead flat for as far as the eye can see
3. unsealed dirt tracks, 100kms of travelling 60km/hr, generally flat terrain
Overall I averaged 12 litres/100 km.
On the open road, highways, I mixed it between sitting at 95km/hr in 6th gear, at just under 2000rpm. Could increase it to 2200rpm at 100-105km/hr and still maintain about 12l/100kms.
Undulating sealed roads, where I'd have to drop down to 4th or 5th to climb an incline, saw the fuel consumption rise to the 13l/100kms.
The dirt roads, sitting in 4th gear, at 2100rpm, and dropping down to 3rd/2nd gear for those wretched cattle grids, up down, up down, and it'd then average 13-13.5l/100kms. Occassionally I'd get it up to 5th gear, 70km/hr, 1600rpmish ... but if I had to slow down, it'd be drop back into 4th.
Now I am home, and have the App, i'll start testing normal regional Vic country driving, into town and back and see how she goes without any towing load.
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22 stx. Think it's 80l
