D40 Fuel Economy

[Escapee]

I'd definitely be asking the person that told you drive with OD off where the hell they get their information from and taking note of it to be sure you never listen to advice from the same source again.

I've also heard this from alot of car dealers when buying new and second hand cars. On delivery of every auto I have ever purchased (5 in total from different dealers) they tell me to turn the OD off around town in 60 zones or less. The issue raised by all of them was that in OD around 60km/ph zones or towing at lower speeds the gear box is shifting too often between 4th and 5th and causes damage that way as it can't decide where it wants to be. De-selecting overdrive ensures minimal gear changing and a more steady fuel supply in speeds of 60km/ph or less. However, I have only ever been told to do this in city roads or tight windey roads as it will slip into 5th for several seconds then back to 4th for a few seconds then back to 5th etc etc etc as the traffic causes you to constantly change your driving style. It will continue on that path - sometimes un-noticed by the driver - for an entire trip (just watch the taco while someone else is driving and you can see it happening and can even feel it). Coincidentally page 5-13 of the Navara Owner's Manual says, "When cruising at a low speeds or climbing a gentle slope, you may feel uncomfortable shift shock as the transmission shifts between 3rd and overdrive repeatedly. In this case, set the overdrive switch in the OFF position"
I've never found this to be an issue on 80km/ph highways and above. If you come to a long hill above 80 it's only going to kick down once per gear. It won't shift up again until you level out so therefore isn't really a problem on highways unless of course you are driving miss daisy.

 

[KraftyPg]

First thing I'd ask anyone who suggested driving with OD off under normal circumstances would be which fuel company they have shares in.

 

[Old.Tony]

Every time I read about this "don't use overdrive" I keep thinking back to the bad old Borg Warner boxes they were whacking in Fords and Holdens back in the 80s.

I know my Nav hasn't got one of those in it, and the first mechanic that suggests I put one of those in can use the Navara's drive shaft as a suppository.

(if you want to know how painful that would be, get underneath and look at how big the bastard is)

 

[STBEA]

well my trip did not go well i got 40ks down the road and a orange light come and i thought the auto was over heating so i pulled over and left her running.... while i was looking through the book after 5 to 10 min i looked out the back of the car and white smoke was pissing out the back ... i turn the car off asap after checking that the car was not on fire i started it up and headed home .. then i looked behind and there as a big pile of white power on the ground . it looks like she spat out the guts of the catilacoverter the dpf system did not like it and put me into lip mode

 

[Old.Tony]

That's amazing but I strongly doubt it's due to the gearbox being in overdrive.

White smoke is usually a sign that there's way too much fuel and it's not being combusted, like the fuel that goes into the exhaust stroke (our D40s do this to both provide the reductant for the CAT and for the DPF's regeneration cycle). That doesn't explain the white powder though - be interesting to find out what that was.

It would have also been interesting to get the error code off the ECU when the light came on. It might have been trying to do a regen because the pressure sensors in the DPF were showing too much difference and you hadn't driven it long enough in a fashion that would allow the regen to occur. This means: 1600rpm or better, light engine load, engine temperature normal. It has to maintain this for around 10 mins to complete a regen - if it can't for a certain number of attempts, it throws the engine light and forces limp mode.

Keep us informed of what happened. Could the CAT have burnt itself out?

 

[Pete22]

well my trip did not go well i got 40ks down the road and a orange light come and i thought the auto was over heating so i pulled over and left her running.... while i was looking through the book after 5 to 10 min i looked out the back of the car and white smoke was pissing out the back ... i turn the car off asap after checking that the car was not on fire i started it up and headed home .. then i looked behind and there as a big pile of white power on the ground . it looks like she spat out the guts of the catilacoverter the dpf system did not like it and put me into lip mode

Which "orange" light are you talking about? I'm guessing that it may have been the DPF light and that is why it has gone into limp mode. Like OldTony says....extremely doubtful that this has anything to do with your gearbox....indeed I'm willing to bet my left testicle that this is so

 

[Pete22]

I've also heard this from alot of car dealers when buying new and second hand cars. On delivery of every auto I have ever purchased (5 in total from different dealers) they tell me to turn the OD off around town in 60 zones or less. The issue raised by all of them was that in OD around 60km/ph zones or towing at lower speeds the gear box is shifting too often between 4th and 5th and causes damage that way as it can't decide where it wants to be. De-selecting overdrive ensures minimal gear changing and a more steady fuel supply in speeds of 60km/ph or less. However, I have only ever been told to do this in city roads or tight windey roads as it will slip into 5th for several seconds then back to 4th for a few seconds then back to 5th etc etc etc as the traffic causes you to constantly change your driving style. It will continue on that path - sometimes un-noticed by the driver - for an entire trip (just watch the taco while someone else is driving and you can see it happening and can even feel it). Coincidentally page 5-13 of the Navara Owner's Manual says, "When cruising at a low speeds or climbing a gentle slope, you may feel uncomfortable shift shock as the transmission shifts between 3rd and overdrive repeatedly. In this case, set the overdrive switch in the OFF position"
I've never found this to be an issue on 80km/ph highways and above. If you come to a long hill above 80 it's only going to kick down once per gear. It won't shift up again until you level out so therefore isn't really a problem on highways unless of course you are driving miss daisy.

The only time I turn OD off is when off road and in low range.....and even then I don't know why I bother because I've never felt that 'shock'. I even use cruise control at low speeds so I don't get booked by the sneaky copper hiding behind a tree or one of those newfangled mobile 'safety' cameras.....the cruise works very effectively a speeds of 50kph and higher.

 

[STBEA]

stbea

well drop my car off to nissan , and the result was a blown catconverter and dpf unit
he said it was prob from all the bad fuel usage i have reported to them and was too blocked when the burn program come on and melted it....... bugger

 

[joe2006]

Lucky it's under warrantee. I reckon that would cost a few bucks.

Wonder what caused the problem in the first place & what will stop it happening again?

 

[Old.Tony]

I'd love to know what did that. DPF runs at about $4,000. The CAT should be cheaper, but it's still an expensive exercise.

What kind of engine oil do you use? If you use one that's not a low-ash formula (eg Castrol Magnatech) you could block the DPF with the ash particles as the oil is combusted (coming from the Positive Crankcase Ventilation tube into the air intake then ingested and burned).

What fuel do you typically use - and importantly, are you filling up from a truck port or a little servo in a side street?

I'm going to re-emphasise my previous comment. It is exceedingly unlikely that this could be caused by the vehicle being in overdrive. My own vehicle's performance is testament to that - I hardly ever pull it out of overdrive. My DPF and CAT are working normally, nearly 70,000km on the dial and going strong. My driving habits MIGHT have something to do with it - I am usually quite gentle with the vehicle.

 

[Pete22]

well drop my car off to nissan , and the result was a blown catconverter and dpf unit
he said it was prob from all the bad fuel usage i have reported to them and was too blocked when the burn program come on and melted it....... bugger

I'm going to take a wild arsed guess here and say that Mr Nissan is going to try and duck out of paying for this if they are already blaming bad fuel ......or do you mean high consumption?

 

[Escapee]

What kind of engine oil do you use? If you use one that's not a low-ash formula (eg Castrol Magnatech) you could block the DPF with the ash particles... .

Crikey, I've been using that. Bought the car at 100,000km and have changed oil twice now and up to 115,000km. What brand do you recommend Tony?

 

[STBEA]

I'm going to take a wild arsed guess here and say that Mr Nissan is going to try and duck out of paying for this if they are already blaming bad fuel ......or do you mean high consumption?

high consumption !

 

[KraftyPg]

What brand do you recommend Tony?

I'm not Tony but I'll take a stab at the most logical answer being "Oil that is the same spec as listed in the owners manual or in the oil thread on this forum".

Specific flavours makes little difference get the rating right and the flavour is your preference.

 

[Escapee]

I'm not Tony but I'll take a stab at the most logical answer being "Oil that is the same spec as listed in the owners manual or in the oil thread on this forum".

Specific flavours makes little difference get the rating right and the flavour is your preference.

I thought I did that with Castrol Magnatec. It was the only one at Supercheap auto at the time I went to do my first service on the d40 that was within spec. Everything else was too thick cold or too thin hot. It even had the same codes as listed in the manual (I know this cause I took the manual with me).

 

[KraftyPg]

I can't remember the exact specs but if you follow the specs in the book then it's the right oil, the main thing is that it is low ash for DPF fitted vehicles. If the letters and numbers match that's all you can ask for.

When I first started buying oil for the Nav the only brand I could find at SCA that matched the exact specs was Nulon and I have been using it since the first service.

 

[Old.Tony]

Crikey, I've been using that. Bought the car at 100,000km and have changed oil twice now and up to 115,000km. What brand do you recommend Tony?

The oil spec - its weight - is one thing that's important for the operation of the engine, but for those of us with DPFs we also need to make sure the formulation of the oil produces the lowest amount of ash possible.

Generally that puts us firmly in the synthetic oil department. It's not easy to make a low ash formula and you'll pay a premium for it - Nissan charge an extra $45 or so for DPF-equipped vehicles during a service because of this.

I've just been through the Castrol web site, they say that their oil meets or exceeds API-CD and CF but it needs to pass CF-4, or JASO-FD.

I'd use the Magnatech in a non-DPF vehicle but it just doesn't quite cut the mustard for the DPFs and given the cost of a DPF ($4,000) I'm not going to risk it. Synthetic oil like Shell Helix Ultra would be a good choice.

I just let Nissan put the oil in - if I'm going to have a problem with the vehicle, THEY are going to fix it for me.

 

[Krankin]

Crikey, I've been using that. Bought the car at 100,000km and have changed oil twice now and up to 115,000km. What brand do you recommend Tony?

Shell Helix Ultra Extra 5W-30,
or castrol Edge Sport 0W-30 or SLX-OEM Professional and many other brands have the right grade/spec oil for you.
or
get rid of the DPF and then just use some RX Super

 

[STBEA]

well got a new pdf unit and new exhaust all going well so far,will know this weekend when towing the trailer.... i must say my nissan dealer was very help full fron start to finnish could not fault a thing !

 

[Docdazzler]

D40 Fuel economy

I'm getting about 9.7 l/100 km 6 spd TD on cruise control in the city & funnily enough sometimes a bit higher country (due to increased speed)