Navara 2010 2.5 diesel fuel consumption
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Wow, great work guys and a good read, no wonder the new STX's don't have the blasted things, obviously Nissan knew there was a problem with them.
I'm keen to find out anyone who has the new AUTO (140kw) with no DPF as standard what their fuel figures are like????
I'm keen to find out anyone who has the new AUTO (140kw) with no DPF as standard what their fuel figures are like????
Arty you can now remove that "stupid factory dump/cat" too - just make sure you pull that connector. I am running 3 inches right thru and it sounds fantastic in my view.. but of course I'd say that.
Can't get video to embed into the page so here's the link...
http://s739.photobucket.com/albums/x...intheSimo2.mp4
apcconstructions
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I agree with all above
My theory in the experiment was once the ECM detects that the O2 sensor has been disconnected it has no option but to disregard it and run on the default fuel map. Maybe the default fuel map with no o2 sensor input will use less fuel as the ECM cannot inject fuel during the exhaust stoke without monitoring it's effects..
For the avoidance of doubt - it is the three-wired pressure sensor connector that needs to be disconnected not the O2 sensor. Regardless, I appreciate what APC is highlighting and I will be recording and posting fuel economy!!
apcconstructions
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OK this is only preliminary but hopefully is good news.
I disconnected the O2 sensor from the ECM and drove the car down the freeway for about 30km, at the same time I connected the multimeter up to the disconnected sensor and it was showing 0.10v nearly the whole time. This is opposed to the 0.75v I was seeing while the sensor was connected.
(remember anything below 0.45 on the O2 sensor means lean and anything above 0.45v means rich mixture)
My thoughts on this was that the ECM was using the O2 sensor to monitor the fuel injected on the exhaust stroke ( to control emissions and conditions for the cat) and that if the o2 sensor was disconnected the ECM could no longer monitor fuel injected on exhaust stroke and therefore could not inject on exhaust stroke.(theory only)
If this is the case then this may be the solution to getting rid of high fuel consumption!!
The only thing that may be wrong with this experiment is that the O2 sensor needs to be heated to 300deg+ in order to give an accurate reading. During my test the heating wires were disconnected but from other sites I have read the exhaust should have reached 300deg+ while driving down the freeway.
Anyway will fill the car up tonight and drive 100km and fill up again. Then we will know for sure!!
I disconnected the O2 sensor from the ECM and drove the car down the freeway for about 30km, at the same time I connected the multimeter up to the disconnected sensor and it was showing 0.10v nearly the whole time. This is opposed to the 0.75v I was seeing while the sensor was connected.
(remember anything below 0.45 on the O2 sensor means lean and anything above 0.45v means rich mixture)
My thoughts on this was that the ECM was using the O2 sensor to monitor the fuel injected on the exhaust stroke ( to control emissions and conditions for the cat) and that if the o2 sensor was disconnected the ECM could no longer monitor fuel injected on exhaust stroke and therefore could not inject on exhaust stroke.(theory only)
If this is the case then this may be the solution to getting rid of high fuel consumption!!
The only thing that may be wrong with this experiment is that the O2 sensor needs to be heated to 300deg+ in order to give an accurate reading. During my test the heating wires were disconnected but from other sites I have read the exhaust should have reached 300deg+ while driving down the freeway.
Anyway will fill the car up tonight and drive 100km and fill up again. Then we will know for sure!!
I've got a feeling the O2 sensor is monitoring the richness, but of the combustion process itself.
Assume for the moment that the injectors do NOT open during an exhaust stroke - let's keep it simple.
When the engine is running lean, there should be a lot of oxygen in the exhaust stream (not enough fuel to consume the air available). The O2 sensor should report - in the Navara's case - a lower voltage.
When the engine is running rich, all of the oxygen has been consumed and there may be excess fuel as well - but by measuring the oxygen level, you know that if all of it has been consumed then you're running rich (enough, or more). This is returned by the Nissan sensor as 1V.
I don't think the fuel injected in the exhaust stroke is actually burnt as part of the combustion process, so it should not affect the O2 levels in the exhaust stream where hte O2 sensor is. For the small amounts sent to the CAT to be used as a reductant, it must arrive in liquid form anyway, so my guess is the injector stroke happens late in the cycle so that the combustion process doesn't ignite the raw fuel early, giving it a chance to get to the CAT.
Be very interesting to see how your experiment goes. Interpreting the manual to determine precisely how it all works is not an easy task!
Assume for the moment that the injectors do NOT open during an exhaust stroke - let's keep it simple.
When the engine is running lean, there should be a lot of oxygen in the exhaust stream (not enough fuel to consume the air available). The O2 sensor should report - in the Navara's case - a lower voltage.
When the engine is running rich, all of the oxygen has been consumed and there may be excess fuel as well - but by measuring the oxygen level, you know that if all of it has been consumed then you're running rich (enough, or more). This is returned by the Nissan sensor as 1V.
I don't think the fuel injected in the exhaust stroke is actually burnt as part of the combustion process, so it should not affect the O2 levels in the exhaust stream where hte O2 sensor is. For the small amounts sent to the CAT to be used as a reductant, it must arrive in liquid form anyway, so my guess is the injector stroke happens late in the cycle so that the combustion process doesn't ignite the raw fuel early, giving it a chance to get to the CAT.
Be very interesting to see how your experiment goes. Interpreting the manual to determine precisely how it all works is not an easy task!
Does the removal throw any warning lights such as occurs when the pressure sensor connector is pulled?
apcconstructions
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no warning light has shown up on the dash so far and I have driven it 3 or four times today - however if you do a diagnostic check then it throws a 0135 code. If this works then it's just a matter of plugging back in before service and then reset ECM..
fingers crossed
fingers crossed
apcconstructions
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There are many types of catalysts and all work in different ways - I was asuming that the diesel is not acting as a reductant - the metal in the catalyst is. The NO gas can only be split up into N2 and O2 by the cat in an oxygen depleted environment. ie if there is too much oxygen in the exhaust then as the No passes through the Cat it cannot be split into N2 and O2 as the O2 prevents this from happening.
When I say extra fuel is injected in the exhaust stroke I probably should have said just after the combustion stroke ( nissan injectors inject multiple times for each compression cycle) so a poofteenth after the combustion cycle an extra squirt may be injected which will still ignite and therefore burn any remaining O2 in the exhaust manifold allowing the cat to do it's job without affecting power of the engine etc etc.
This is all speculation and after this I might become an automotive engineer!!
One thing that let me to think this is the way the emission control is working was that I was using the same amount of fuel during urban driving as i was doing 400km long trips on the hwy.(14.5l100km)
The emission control by the ECM can only work while the car is been used in a steady manor like on the freeway or hwy. The emission control can not take place in an urban environment as the car is accelerating and decelerating too much for it to be effective.
This week I drove the car really hard and flogged it at every set of lights with no freeway driving and guess what I still got about 14.5. When I drive it real carefully on the hwy I still get 14.5. I am assuming this is because during the urban driving the ECM is not injecting the extra fuel to run the car rich otherwise I would have expected to get around 16 - 17 L100km
When I am doing a lot of freeeway driving then the ECM is in emission control mode and any saving of fuel economy is being wasted by trying to run the car rich - extra fuel injected.
Anyway this could all be a load of guff and we will see what happens after I have done 100km with the sensor unplugged!!
stay tuned!! - my nissan obviously isn't
That's very intriguing, that you get the same mileage figures. We don't - our figures are definitely in line with the kind of driving we're doing.
General city driving, stop-start in traffic with 10 to 20 minute journeys - 12 to 14 LPHK
Highway, not towing, few hills - 10.4 to 11 LPHK
Highway, not towing, hills and forests - 11 to 12 LPHK
Highway, towing, few hills - 16 to 18 LPHK
Highway, towing, mountains - 18 to 22 LPHK
Vehicle is 2500Kg on the kerb, van is 1800Kg double-axle.
It sounds to me like your ECM isn't modifying the fuel map at all - like it's stuck in the one mode. I hope you get some results from this, there are a few people here that are also suffering high consumption figures that would benefit from this discussion and your findings.
On the CAT operation - the metal in the CAT causes the breakdown, but it needs a hydrocarbon as a reductant - that's the fuel. Yes the environment needs to be oxygen-depleted, that's why the O2 sensor is there so that the fuel metering can be adjusted so the combustion process results in an oxy-depleted environment, into which they then squirt an extra dose (which can't burn, no oxygen) that becomes the reductant on the surface of the CAT.
Complex little shits these things, and sometimes confusing. I hope we can eventually clear it all up by understanding it ourselves - more than a few of us will come out with a great deal more knowledge than we had before. I like that.
General city driving, stop-start in traffic with 10 to 20 minute journeys - 12 to 14 LPHK
Highway, not towing, few hills - 10.4 to 11 LPHK
Highway, not towing, hills and forests - 11 to 12 LPHK
Highway, towing, few hills - 16 to 18 LPHK
Highway, towing, mountains - 18 to 22 LPHK
Vehicle is 2500Kg on the kerb, van is 1800Kg double-axle.
It sounds to me like your ECM isn't modifying the fuel map at all - like it's stuck in the one mode. I hope you get some results from this, there are a few people here that are also suffering high consumption figures that would benefit from this discussion and your findings.
On the CAT operation - the metal in the CAT causes the breakdown, but it needs a hydrocarbon as a reductant - that's the fuel. Yes the environment needs to be oxygen-depleted, that's why the O2 sensor is there so that the fuel metering can be adjusted so the combustion process results in an oxy-depleted environment, into which they then squirt an extra dose (which can't burn, no oxygen) that becomes the reductant on the surface of the CAT.
Complex little shits these things, and sometimes confusing. I hope we can eventually clear it all up by understanding it ourselves - more than a few of us will come out with a great deal more knowledge than we had before. I like that.
apcconstructions
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BANZAI!!!
Drove the car for 117km and filled up to the brim and used 13.1L. This was driving on freeway at 110km/hr - Thats 11.2L 100km - I could never get under 14L 100km before.
(2010 king cab stock with steel tray and bullbar)
This was with the O2 sensor unplugged and with a 50mm hole punched through the DPF.
And I also was using BP ultimate which I find was loosing about 50-80km to a tank before so with a std diesel these figures may be even better!!!
The check engine light did come on but that is a small problem that I think I can overcome as my brother is a computer programmer and some creative circuity is needed that I think can be designed..
Anyone interested??
Drove the car for 117km and filled up to the brim and used 13.1L. This was driving on freeway at 110km/hr - Thats 11.2L 100km - I could never get under 14L 100km before.
(2010 king cab stock with steel tray and bullbar)
This was with the O2 sensor unplugged and with a 50mm hole punched through the DPF.
And I also was using BP ultimate which I find was loosing about 50-80km to a tank before so with a std diesel these figures may be even better!!!
The check engine light did come on but that is a small problem that I think I can overcome as my brother is a computer programmer and some creative circuity is needed that I think can be designed..
Anyone interested??
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Interested? Interested? More totally consumed by this subject I am determined to run my D40 with a DPF delete and highflow dump/cat.
Tomorrow morning I am pulling my DPF back out and for experimental purposes I am trying the alfoil / O2 probe wound right out of the pipe.
Awesome sounds good mate! Did you get stuck in limp mode or just the light? I can live with a check engine light its just limp mode that sucks!
No limp mode Josh just the amber check light. Not a perfect solution but a workable one.
Is that with the O2 sensor unplugged or the pressure sensor unplugged? or both?
cheers cant wait to get home and try this on mine!
Chip Tuning
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Boss you need one of our DPF Race pipes 
Dont bugger the OEM unit. Those OEM units cost $3000 to replace ... and you may be able to sell it at a later date
Dont bugger the OEM unit. Those OEM units cost $3000 to replace ... and you may be able to sell it at a later date
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Beergutz
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Great read gents. Bosshog 3m make an aluminium foil tape. It is an adhesive foil tape that is used in the catering industry. It is used for wrapping around drain pipes on fry vats used in McDonalds ect. It helps by distributing heat from heater tape that you tape to the pipes and keeps the shortening from going hard. It may be just what you need to solve your 15% problem with aluminium foil coming away. Is sticky as hell as you can imagine having to use in oily environments. Just might do the job for ya???????
It would be interesting to find out what DTC is generated by the CEL coming on.
It is possible that after a certain amount of time operating with that warning flashing that the engine will go into limp mode, or will go back to factory default fuel map, which is the over-rich map.
The sensor doesn't just need to detect no oxygen - it needs to respond to changes that the ECM is making in an appropriate time. That's why the CEL came on (we discovered this little feature earlier). This means that simply disconnecting the O2 sensor or covering the surface with a heat-proof paint (haha, that'd fool it!) will still throw the CEL.
What's needed to defeat it is either an ECM reprogram, or the ability to ignore injector commands during exhaust strokes - so we're still back to something like a power chip IF we want no CEL to appear.
I would be interested in the long-term effect of having the O2 sensor disconnected. Does it push the vehicle into limp mode, or default fuel map mode? Everyone else is watching too, because if the ONLY thing that ever happens is the appearance of the CEL, it's a cheap means of saving fuel - although, and I can't stress this enough, this also means that when something DOES go wrong, you won't see the CEL light come on - hopefully we'll never see that, but we know things can go pear-shaped.
It is possible that after a certain amount of time operating with that warning flashing that the engine will go into limp mode, or will go back to factory default fuel map, which is the over-rich map.
The sensor doesn't just need to detect no oxygen - it needs to respond to changes that the ECM is making in an appropriate time. That's why the CEL came on (we discovered this little feature earlier). This means that simply disconnecting the O2 sensor or covering the surface with a heat-proof paint (haha, that'd fool it!) will still throw the CEL.
What's needed to defeat it is either an ECM reprogram, or the ability to ignore injector commands during exhaust strokes - so we're still back to something like a power chip IF we want no CEL to appear.
I would be interested in the long-term effect of having the O2 sensor disconnected. Does it push the vehicle into limp mode, or default fuel map mode? Everyone else is watching too, because if the ONLY thing that ever happens is the appearance of the CEL, it's a cheap means of saving fuel - although, and I can't stress this enough, this also means that when something DOES go wrong, you won't see the CEL light come on - hopefully we'll never see that, but we know things can go pear-shaped.
apcconstructions
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Exactly B T not really a good idea to be driving with the CEL light on all the time- all that I have done so far is maybe prove that disconnecting the O2 sensor prevents the ECM from monitoring and therefore managing the extra fuel injection for the emission control of the vehicle. I will need to clock up some more km to see if the car goes into limp mode and if the good results continue. I will also need to plug the sensor back in and do another fuel test to make sure that the consumption does go back up with the sensor connected.. Fingers crossed.
With regards to stopping the CEL from appearing I have a very good idea on how this can be achieved with a quick and easy plug in module at the O2 sensor which fools the ECM and can be removed in seconds for car servicing. Requires computer chip and programming etc i have the contacts and things are underway. hopefully within the next few weeks after some testing I will have some good news.
Will keep everyone posted on the fuel usage on the next tank of fuel.. I guess everyone can try the test themselves if they are game!!!
