D40 Fuel Economy

[justdrinkbeer]

Had my truck over the weigh bridge the other day, 2520kg's as I drive it day in day out.
Suppose the stop start driving, muddies & weight means the economy figs i'm getting.
Interestingly I did a fuel reset and it didn't change it one jot.

 

[Old.Tony]

Given just the raw weight, you should expect (on paper) 13.6LPHK (auto) or 13.78 (manual), then add a bit for the muddies. Stop-start with any heavy vehicle is a killer, you use most of your fuel getting the vehicle up to speed, as you'd know (but some may not, so explaining for other readers).

Fill the tank, sit on a freeway for 300-400km and fill it again and see what figures you get. That'll at least tell you if it IS the stop-start making its presence felt.

 

[KraftyPg]

Interestingly I did a fuel reset and it didn't change it one jot.

As far as fuel resets and ECU resets go there wont always be results good or bad after doing these procedures. I've done the resets myself and wouldn't suggest that people don't try them because as has been said previous they don't appear to do any harm but also we shouldn't all expect them to make some sort of difference either.

According to my information (which can be taken with as many grains of salt as any other persons) different dealers do these resets at different times, some do them pre delivery, some claim they shouldn't need it until after the service and some claim they only need it if there is problems. I'm not sure there is a definitive answer as to when they need them but if there was any positive effects coming from a reset and the reset was done pre delivery then it stands to reason that further improvements may not happen with each subsequent reset, at least not for a while after wards anyway.

 

[4wdchip]

Hey Guys & Girls,

We have just finished our D40 AUTO Exhaust .... 100% legal, 3" DUMP and 3" system that keeps your original DPF in place. A customer today has picked up 130Klms to a tank of fuel when towing! He is wrapped.

 

[Leprechaun]

130 extra klms per tank????

Sorry.... I don't think so.

 

[Old.Tony]

I find that astonishing. Let me do some math.

We've been getting 18LPHK when towing. 80 litres * 100 / 18 = 444km range

In order to get 574km we'd need to get 80 * 100 / 574 = 13.9LPHK.

That's a 4LPHK improvement, or about 29% better economy. It's like saving over $20 a tank.

I would be astounded to get such an increase in economy just from an exhaust change.

 

[Leprechaun]

If Nissan engineers could have improved fuel useage by 29% by increasing the exhaust size. they would have done so.

 

[4wdchip]

It is huge, and I can only go off what my customer told me.... remember though this is a Auto and only while towing a heavy boat.
you certainly would get that sort of increase with every day driving

 

[4wdchip]

If Nissan engineers could have improved fuel useage by 29% by increasing the exhaust size. they would have done so.

The 3" is a tight fit, it has good clearance for fitment by hand but I would doubt a production line would handle it.

 

[bigfluffys]

After reading about 200000000 posts i took the plunge and had a full 3 inch system fitted today from the turbo back, all pipe, no cat, dpf muffler.

Now, for those thinking of doing this it is THE BEST upgrade possible for power!

The thing hammers, the turbo spools up heaps faster, you can hear the turbo whistle, Very small amount of engine noise, just nice.

We will see in the comming weeks to how the fuel acconomy goes.

the flex pipe in the stock system is 2 inch inside restricting the thing, the cat chokes it up like you wouldn't believe.
Ive got LPG fitted, and runs a small amount before the turbo making it clean burning, no black smoke at all.

Also got more power diesel chip fitted.

its a totally different car.

if you are thinking of doing it, dont hesitate.

Ill be in touch with fuel figures as soon as i have some.

Hi , how much did this cost , is it still legal without dpf ??

 

[Old.Tony]

Hi , how much did this cost , is it still legal without dpf ??

It's illegal to modify or remove any of the emission control systems fitted to a vehicle.

However, the chances of being caught are probably very slim. A full pit inspection might reveal it, or an examination of the vehicle after a traffic incident.

The guy that does your pink slip probably wouldn't even bat an eyelid.

 

[bigfluffys]

You can reset the ECU yourself by following the instructions found here.

I've done this, the vehicle was not damaged in any way, it behaved exactly as before - no noticeable coughing, spluttering or rapid left turns when driving past the local member of parliament's offices. If it's done anything, it has helped provide me a better-than-expected fuel economy - but it didn't do any harm. Nissan have seen the vehicle since and didn't draw anything to my attention, so they didn't notice.

Hi tony , i did the reset today after the reset do you know what it means if the eml flashes (i think) ten times slowly the 10 times fast and i think ten times fast again , not sure if there is a problem or not , and im also a little unsure if it was exactly 10 flashes , i was panicking at this point as i was in the middle of driveway and was worried that the car would now not start or self combust and turn into a transformer and take over the world so i started the car hence loosing track of the flashing ect ect , can i do it again ?? is it going to do any damage , cheers

 

[Old.Tony]

I don't think it'll do any damage, the flashing is a message to the Nissan techs that indicate a code that they need to pay attention to. 10 flashes might be "operation incomplete" or "Christ on a Bike the beer's warm!" for all I know.

Turning it off or on and interrupting the sequence was probably the best thing. Try it again and see what happens. Mine didn't work first time, the timing is a little important.

 

[JPMC]

Flashes indicate what faults if any are present or stored.

10 flashes is 0 so if you had 10 slow flashes followed by 3 lots of 10 flashes fast it means 0000 which indicates no faults found or stored.

Interupting the sequence wont do anything and resetting the system may not achieve anything either as there is no faults but you may find that with the onset of winter if your engine is sounding a bit noise on cold mornings by doing the reset it will help to quiet it down as the ecu will adjust fuel flow for colder temp.

Note: always do the reset once the engine is up to temp.
and to complete reset you have to hold down the accelerator pedal for 10 seconds to clear all (if any) the faults and reset the fuel system.

 

[justdrinkbeer]

Hey Guys & Girls,

We have just finished our D40 AUTO Exhaust .... 100% legal, 3" DUMP and 3" system that keeps your original DPF in place. A customer today has picked up 130Klms to a tank of fuel when towing! He is wrapped.

Put it on my D40 Auto for free & get me 130km more to a tank of fuel and i'll pay for the system & give you the cash I save over the next year!

That would be 500km's around town, as it is & has been for a year now.

 

[KraftyPg]

Note: always do the reset once the engine is up to temp.
and to complete reset you have to hold down the accelerator pedal for 10 seconds to clear all (if any) the faults and reset the fuel system.

Is that actually documented, can't say I've read on any forums or such that the car needs to be at any temp when doing the reset.

 

[blue22]

Is that actually documented, can't say I've read on any forums or such that the car needs to be at any temp when doing the reset.

Over on the LS1 forum the reasoning to have all up to operating temp was for the relearn process so the fuel/air mixtures will be set correctly.

They say drive car for 10 minutes, reset ECU, take car for an easy drive, don't drive too hard, run thru the gears without revving too hard.

A reset is always a good idea when changing fuel types(91-95-98 so on), many manufacturers tune at 95 and have fall back tables for 91. Some only tune at 95 and rely on knock sensors to pull out timing if detonation is sensed due to low octane fuel being used.

My commodore LS1 was tuned for 98 with a 95 table added so that when 98 is unvailable(wasn't always available here in Perth a couple years ago) the tune falls back to the other table.

 

[Old.Tony]

Guys, I'm compiling all of these tips into a single set of instructions with links back to the original posters' posts so that credit can go to those who provided the info. I think those who want to give it a go should and please post feedback in here so we can make this accurate. Also, if you find it difficult to follow, send me a pm and I'll do what I can to clear things up.

Here it is, so far:
_____________________________________________________________________________
Original post: Exhaust mod with DPF post 27081

Modifications to refine procedure are in bold.

D40 ECU RESET PROCEDURE
To carry out the reset do the following:

Warm up the vehicle to normal operating temperature then turn the vehicle off.

Turn ignition on so all dash lights come on.

Wait 3 seconds.

PUMP accelerator pedal 5 times within 5 seconds....

With foot now OFF accelerator wait 7 seconds...

After 7 seconds press and hold down accelerator pedal for 10 seconds...

After 10 seconds the Engine Management Light will start to flash, at this point remove foot from accelerator.

The Nav is now in diagnostics mode, so let the EML flash for a bit. Then press and hold the accelerator pedal down for more than 10 seconds - this will then reset ECU and fuel pump etc and put them into learning mode.

Holding the accelerator for that long ends the procedure.

From D40 Fuel Economy page 26 post 36741:
DO NOT TURN THE IGNITION OFF. Take the vehicle for a nice gentle drive, go through all the gears and then shut the vehicle down to finish the learning process.

NOTE: When the EML light is flashing, this is listing possible fault codes... so if you know how to read the fault codes or know the sequences then you can figure out any possible faults with your Nav with out getting the dealer to do it!!

From D40 Fuel Economy page 26 post 36627:
Seeing 1 set of 10 slow flashes followed by 3 sets of 10 flashes fast means there are no faults found or stored.

 

[KraftyPg]

On the note of economy this week I while heading down to Melbourne the low fuel light came on about 60ks out from the burbs. First thing I did was check the scangauge for the remaining litres and it was claiming 12.8 which I knew was going to get me into the burbs where I had a few things to do before heading home.

Along the remaining part of the Princes Hwy and onto the SE carpark I sat on cruise at 96ks dropping to 93ks as the traffic picked up a bit on the car park. Traffic along Centre Rd to Oakleigh was it's usual crap of traffic lights and Melbourne drivers but it was flowing fairly well. After Oakliegh it was back along Clayton and Heatherton Rds to Noble Park then after a stop in Noble Park it was Heatherton Rd to the SE carpark.

All this time I was watching the scangauge and according to it I was down to 7 litres when I exited the SE carpark at Ernest Wanke Drive. It was at that time the engine farted a few times and there was a brief loss of power but only for 2 seconds max. I kept going to Fountain Gate, then to JB Hi Fi and then at the servo near JB I put 78.76 litres in the tank.

After filling I worked out the scangauge was out by about 2.4 litres (so the 12.8 was actually about 10.4 and to me is still acceptable) and that a bit over 90ks including the burbs traffic is doable after my light comes on. Not sure I'd have been so willing to push the thing without having the scangauge but still atleast I know mine is going to fart and carry on just a little bit before it stops completely.

For the record that LPH in that last 10 litres was a shade over 10lph while the total tank according to scangause was 9.7 however the majority of that driving was highway driving and not heaps of stop start.

 

[chris the chippy]

The 3" is a tight fit, it has good clearance for fitment by hand but I would doubt a production line would handle it.

HEY GUYS!!
just reading this post and seen that you have done 3inch for the autos with the dpf. Had a look on your web site but now info on it like priceing or dyno sheets. Would be intersting to see!! Might of sold me on one!