R51 Pathfinder (D40 2.5 TD) Poor Fuel Economy

[DarwinPathfinder27]

Hey everyone, I drive a 2009 Pathfinder Diesel, which I know shares the same drivetrain as the D40 Nav. I picked it up in Brisbane with 270kkm on the clock, and drove it back to Darwin where I live - I didn’t manage to achieve any better than 530km to a full tank of diesel, and since I’ve gotten back here, I’ve had white smoke being expelled from the exhaust at low speeds and at idle, with the fumes coming through the air vents in the cabin. I’ve since had the DPF manually regenerated, the MAF sensor cleaned (was dirty and caked in gunk) and the radiator replaced, and had a full service and oil change done. After the service it was running great with much more power for the first few days, felt like a brand new car, but since then it’s gone downhill, it feels even more down on power than it did previously, and since filling the tank, it’s done 280km and I’m already down to under a quarter of a tank.. this economy seems to me like it’s running rich. Does anybody have any suggestions around what it could be, whether it’s mechanical or perhaps the previous owner may have messed with the computer and tuned it in a particular way? I’m really concerned and am almost at the point of trading it in but, any suggestions would help if it means I get to hold onto it, other than this, it’s been a good vehicle. Thank you in advance!
Dave

 

[GunMentalGrey]

2009 seems a ripe age for brittle vacuum hoses. May not be getting proper boost.

 

[DarwinPathfinder27]

2009 seems a ripe age for brittle vacuum hoses. May not be getting proper boost.

I suppose that is a possibility, but would this be indicative of extremely poor fuel economy too?

 

[GunMentalGrey]

When I had a cracked vacuum hose and was down on boost I was using extra fuel, and making copious black soot, because the right foot had to push harder for the same effect.

It’s possible there are other issues, just something to look for and is a cheap fix. I think it’s 3m of 3mm vacuum hose reqd. old tony on here has mentioned it plenty of times.

 

[Old.Tony]

Perished vacuum hoses could be the answer. The YD25 in the D40 depends quite heavily on the output of the turbocharger for its power and without the turbo, it blows significant amounts of black smoke and feels gutless. I've had this when my hoses perished, replaced them with 3mm vac hose from Supercheap Auto (you need about 3 metres of it).

However, I had a similar experience when my turbocharger failed (black smoke produced). Checked hoses - all ok. Checked the shaft of the turbo - wobble-wobble, so out it comes. Running a genuine Honeywell Garrett that we purchased from Brisbane now, and it doesn't miss a beat.

Another cause of this problem (with black smoke) is a failure in the Boost Control Solenoid. Mine's failed twice, and has now been replaced by a Tillix valve.

When my car started performing normally but chucking out clouds of white smoke (stinky white smoke at that) it ended up being the sensors front and rear of the DPF. Having a mechanic reset the DPF routine ($50 thank you) gave me about 200km of trouble-free motoring after which the car decided it was time to regen again and started producing more white clouds than the whole of Nimbin combined. A message to @auggie on this forum and a few hundred $ later I was in possession of two replacement sensors that worked an absolute treat and I've had NO problems since.

 

[Phunk]

Perished vacuum hoses could be the answer. The YD25 in the D40 depends quite heavily on the output of the turbocharger for its power and without the turbo, it blows significant amounts of black smoke and feels gutless. I've had this when my hoses perished, replaced them with 3mm vac hose from Supercheap Auto (you need about 3 metres of it).

However, I had a similar experience when my turbocharger failed (black smoke produced). Checked hoses - all ok. Checked the shaft of the turbo - wobble-wobble, so out it comes. Running a genuine Honeywell Garrett that we purchased from Brisbane now, and it doesn't miss a beat.

Another cause of this problem (with black smoke) is a failure in the Boost Control Solenoid. Mine's failed twice, and has now been replaced by a Tillix valve.

When my car started performing normally but chucking out clouds of white smoke (stinky white smoke at that) it ended up being the sensors front and rear of the DPF. Having a mechanic reset the DPF routine ($50 thank you) gave me about 200km of trouble-free motoring after which the car decided it was time to regen again and started producing more white clouds than the whole of Nimbin combined. A message to @auggie on this forum and a few hundred $ later I was in possession of two replacement sensors that worked an absolute treat and I've had NO problems since.

While we are on the talk of regen, does it always have to be done manually with the whole 3rd gear 80km/h on a freeway or is the car clever enough to to boot in an Auto regen on it's own? (or can I activate it myself with an OBD tool?)

 

[Old.Tony]

It's never manual. Certain conditions must be met for it to start, but the ECU makes that call. From memory, the conditions are: engine RPM > 1500 (1600?), coolant temp > 75 celcius, vehicle in gear, engine load < 75% (might be 80%). So you can prevent it from happening, but that's not easy, since the car can so easily meet those criteria.

I don't know if your tool will kick-start a normal regen. Nissan's Consult3 tool will start a "forced regen", and Nissan will charge you for doing it. A forced regen (car sits in neutral, handbrake on, revving the shit out of itself) is so taxing on the engine they recommend an oil and filter change immediately after (and Nissan dealers will do that and extract your left nut to pay for it). It's not something I'd look at doing very often.*

* Not only because of the stress on the motor, but I'd find myself completely out of stock of left nuts after the first regen.

 

[Phunk]

It's never manual. Certain conditions must be met for it to start, but the ECU makes that call. From memory, the conditions are: engine RPM > 1500 (1600?), coolant temp > 75 celcius, vehicle in gear, engine load < 75% (might be 80%). So you can prevent it from happening, but that's not easy, since the car can so easily meet those criteria.

I don't know if your tool will kick-start a normal regen. Nissan's Consult3 tool will start a "forced regen", and Nissan will charge you for doing it. A forced regen (car sits in neutral, handbrake on, revving the shit out of itself) is so taxing on the engine they recommend an oil and filter change immediately after (and Nissan dealers will do that and extract your left nut to pay for it). It's not something I'd look at doing very often.*

* Not only because of the stress on the motor, but I'd find myself completely out of stock of left nuts after the first regen.

Thanks heaps!

Sounds like I might just take it for a freeway drive for an hour or so to make sure it's clearing out.

The scanner I've got forces re-gen's on other cars and have used it in the past, just not on the Navara as of yet.. I'd rather go for the longer drive option than it revving itself in the driveway.

 

[Billbo]

Hey everyone, I drive a 2009 Pathfinder Diesel, which I know shares the same drivetrain as the D40 Nav. I picked it up in Brisbane with 270kkm on the clock, and drove it back to Darwin where I live - I didn’t manage to achieve any better than 530km to a full tank of diesel, and since I’ve gotten back here, I’ve had white smoke being expelled from the exhaust at low speeds and at idle, with the fumes coming through the air vents in the cabin. I’ve since had the DPF manually regenerated, the MAF sensor cleaned (was dirty and caked in gunk) and the radiator replaced, and had a full service and oil change done. After the service it was running great with much more power for the first few days, felt like a brand new car, but since then it’s gone downhill, it feels even more down on power than it did previously, and since filling the tank, it’s done 280km and I’m already down to under a quarter of a tank.. this economy seems to me like it’s running rich. Does anybody have any suggestions around what it could be, whether it’s mechanical or perhaps the previous owner may have messed with the computer and tuned it in a particular way? I’m really concerned and am almost at the point of trading it in but, any suggestions would help if it means I get to hold onto it, other than this, it’s been a good vehicle. Thank you in advance!
Dave

Have you had the timing chain replaced, should have it done every 100k I’ve upgraded to double row chain top and bottom, does make a difference