Hi I've just started driving my diesel Navara and believe my fuel usage is fairly high. I just did a country run keeping to 100km/h most of the time. The fuel economy worked out to be 15.5l per 100km/h. Even though I was pulling a trailer with a light load for half of it I didn't think it would be that high. If that is unusual any idea what could be the problem?. I've just had the timing chain replaced and the injectors had to be re-registered
D40 fuel economy
- Thread starter sklag1
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The older cars aren't as efficient as the new ones, but it does seem like you're using a little more fuel than you ought to.
Things that make fuel consumption go up:
1) Going faster. We do sometimes need to do it, but know that these utes aren't built for their sleekness, they're built to hold stuff and go places you wouldn't take a McLaren. Peak power for boost occurs at around 80-85km/h, so below this you're not "in the zone" and above it you're exponentially using more fuel to go faster.
2) Gadgets like roof racks, rooftop tents etc. Sometimes we need these things, but they make a bad problem worse.
3) Accelerating an auto too far from the stall point. Our autos have a stall point around the 2700rpm mark, so that's where your peak non-TCC-locked efficiency is when accelerating. Taking off at, say, 1800-2000rpm does put the engine in its peak torque zone, but wastes too many RPM to the torque converter slipping.
4) Dirty filters. Mostly it's the air filter that causes consumption issues, but both it and the fuel filter need to be clean. A dirty (or worse, damaged) air filter can allow particles past and if these lodge in the MAFS the car won't be able to get a good read on the air flowing and won't get the fuel mix right (so consumption will rise).
5) Binding/grabby brakes. It's always a good idea when doing a tyre rotation to check each wheel for smoothness of rotation (and check the bearings while you're at it). If you find the wheel hard to spin, you might have grabby brakes.
6) Too many gadgets, particularly in front of the grille (like big driving lights plus a light bar plus a winch and its control box). Blocking direct flowing air to the intercooler/radiator will reduce their effectiveness. The ECU doesn't read air temps after the intercooler, it reads them in the MAFS and knows that compressing to a particular boost level raises the temperature by a certain amount, and the supplied intercooler reduces the temperature by a certain amount. If that intercooler isn't cooling enough, the density of available oxygen in the combustion chamber will be reduced and the power will be reduced (meaning you'll use more fuel to do the same work). You'll also produce more black smoke.
There's a few things anyway.
Things that make fuel consumption go up:
1) Going faster. We do sometimes need to do it, but know that these utes aren't built for their sleekness, they're built to hold stuff and go places you wouldn't take a McLaren. Peak power for boost occurs at around 80-85km/h, so below this you're not "in the zone" and above it you're exponentially using more fuel to go faster.
2) Gadgets like roof racks, rooftop tents etc. Sometimes we need these things, but they make a bad problem worse.
3) Accelerating an auto too far from the stall point. Our autos have a stall point around the 2700rpm mark, so that's where your peak non-TCC-locked efficiency is when accelerating. Taking off at, say, 1800-2000rpm does put the engine in its peak torque zone, but wastes too many RPM to the torque converter slipping.
4) Dirty filters. Mostly it's the air filter that causes consumption issues, but both it and the fuel filter need to be clean. A dirty (or worse, damaged) air filter can allow particles past and if these lodge in the MAFS the car won't be able to get a good read on the air flowing and won't get the fuel mix right (so consumption will rise).
5) Binding/grabby brakes. It's always a good idea when doing a tyre rotation to check each wheel for smoothness of rotation (and check the bearings while you're at it). If you find the wheel hard to spin, you might have grabby brakes.
6) Too many gadgets, particularly in front of the grille (like big driving lights plus a light bar plus a winch and its control box). Blocking direct flowing air to the intercooler/radiator will reduce their effectiveness. The ECU doesn't read air temps after the intercooler, it reads them in the MAFS and knows that compressing to a particular boost level raises the temperature by a certain amount, and the supplied intercooler reduces the temperature by a certain amount. If that intercooler isn't cooling enough, the density of available oxygen in the combustion chamber will be reduced and the power will be reduced (meaning you'll use more fuel to do the same work). You'll also produce more black smoke.
There's a few things anyway.
Hey mate, we had issues with them early on with poor earths. I’d recommend removing all earth points you can access and removing paint from under them. The bolt earthing via the thread only isn’t the best. Personally saw a D40 YD25 auto drop from 14L/100km down to 10 just by doing this. Worth a shot!
No problem.
It’s been 9 years since I left Nissan
, but from memory there were more than 5 worth doing. Any at all you find won’t hurt to check/clean!
It’s been 9 years since I left Nissan
, but from memory there were more than 5 worth doing. Any at all you find won’t hurt to check/clean!
