D4 fuel gauge accuracy

[dwaters]

Hi all, most of you are probably aware the fuel gauge on the D4 is not accurate.
Mine says 0km to empty and there's still at least 12 litres left in the tank.....
I can pretty safely get another 100kms once the gauge indicates 0km to empty...
Also my speedo is out by approx 4km/h.

Does anyone know of a fix for these annoying problems?
Cheers
Darren

[Beery]

Think you'll find most modern cars are the same. The first is to prevent nitwits running out of fuel. The second is to help stop getting speeding fines and I'd say allow for a margin of error in speed cameras.

[PerthDisco]

I went with my mate in his brand new SDV6 on my recent trip to the Pilbara. While we both showed the same approx l/100km his distance to go was completely different to my MY08. Like 100km different by half full. It caused him major panic at one point when he scrounged a few litres at Karijini to get to Tom Price. Mine was showing 40km to go when I filled up. Adjusting for the extra litres he took at Karijini he actually took a few litres less than me since the last fill up! Completely whacko so must be conservative for the paranoia around running out that has crept into the D4. Geez those D3s were so well sorted.[emoji106][emoji10]

[BMKal]

I've never run mine that close to empty, so can't help on fuel gauge accuracy. With the type of long range tank I have fitted, my fuel gauge doesn't work at all (permanently shows "full") for the first 1,000 k's or so from filling - and then the needle begins to move as I use up the fuel in the original tank.

But your speedo is pretty normal. You will find this level of error in ALL new cars sold in Australia - it is required by law to comply with the ADR's. In fact, yours is probably more accurate than most. Mine was about 6km/hr low at around 100km/hr when I was on the OEM fitted tyres. Since fitting slightly larger diameter tyres, the error has now reduced to about 4km/hr under at around 100km/hr.

I can correct the error using my IID Tool if I wanted to, but it's not really something that bothers me.

[Narangga]

Hi all, most of you are probably aware the fuel gauge on the D4 is not accurate.
Mine says 0km to empty and there's still at least 12 litres left in the tank.....
I can pretty safely get another 100kms once the gauge indicates 0km to empty...
Also my speedo is out by approx 4km/h.

Does anyone know of a fix for these annoying problems?
Cheers
Darren

Stated fuel capacity for D3 & D4 is 82L.

On a recent trip I had 70km distance to run and when I filled up it took 79.22 litres! :o

Some extensive searching and I found the LRA specification for MY2015 which state a usable fuel capacity of 82.3L. Hence with a few more clicks of the bowser then I would suggest/estimate as many as 3 more litres could be added. That may then give a usable of around 85 litres.

I also filled up on that trip with the gauge sitting exactly at half and it took 47 litres. I know that I can't fit 94 litres in though. :(

[PerthDisco]

Another difference between the two cars was radio reception. I had some AM for most of the way between Meekatharra and Newman to listen to the AFL Grand Final. The new Disco could not [emoji106][emoji106]

[Tombie]

Radio - Different tint will impact that as well...

Fuel gauge - after I crushed the rear of my tank I'm guessing the rear sender is out of whack... I get 600km to the empty mark and never get more than 60l per fill...

Guess I need to fix that up one day!

[PerthDisco]

Radio - Different tint will impact that as well...


Yes he had tint applied

[Redback]

We adjusted our speedo with our faultmate, it's as close to accurate as you can get them, reading 100kph it's 99kph by the GPS.

Our longrange tank is gravity fed like BMKal so it's full until it goes to the main tank, I've never trusted the fuel guage on the D4, the old D2 was much more accurate, and don't get me started on the cruise control:censored: useless bloody thing it is.

[Tombie]

G'day Baz... how have you been mate?

[Redback]

Good mate and you?

[Tombie]

Good mate and you?



I'd say I've been kicking back relaxing but I've been hunting full time work - my industry of choice has been rather quiet on that front until recently.

Other than that - getting offroad where I can, doing obstacle races as often as possible and generally living the dream!!

[Nicky]

[QUOTE=Tombie;2608199].. my industry of choice has been rather quiet on that front until recently?.

and what would that be?

[Tombie]

[QUOTE=Tombie;2608199].. my industry of choice has been rather quiet on that front until recently?.



and what would that be?



Mining is the preferred profession at this point in life.
Supply Chain, Planning, Production and Operations

I am enjoying consulting in the field however the jobs are few and far between at the moment - working on a strategic review at the moment.

[Redback]

I'd say I've been kicking back relaxing but I've been hunting full time work - my industry of choice has been rather quiet on that front until recently.

Other than that - getting offroad where I can, doing obstacle races as often as possible and generally living the dream!!

Sounds good, I'm in a similar situation, looking for part time work, I'm back into touring on bikes again(on the BMW) and riding the H2 on club days for fun, preparing for our Kimberley trip and generally kicking back and enjoying life.

[Milton477]

[quote=Nicky;2608208]



Mining is the preferred profession at this point in life.
Supply Chain, Planning, Production and Operations

I am enjoying consulting in the field however the jobs are few and far between at the moment - working on a strategic review at the moment.

I am also finding my chosen profession a bit lean at present. In fact, I even painted the front of my shed 3 years after building it. I like the idea of a strategic review however. Sounds like something I could do in my office where there is aircon. Thanks for the idea Tombie.

[PerthDisco]

[quote=Tombie;2608241]



I am also finding my chosen profession a bit lean at present.


A common theme at the moment!

[orville]

Stated fuel capacity for D3 & D4 is 82L.

On a recent trip I had 70km distance to run and when I filled up it took 79.22 litres!
:o


Some extensive searching and I found the LRA specification for MY2015 which state a usable fuel capacity of 82.3L. Hence with a few more clicks of the bowser then I would suggest/estimate as many as 3 more litres could be added. That may then give a usable of around 85 litres.

I also filled up on that trip with the gauge sitting exactly at half and it took 47 litres. I know that I can't fit 94 litres in though.


I was travelling along a suburban street and knew my fuel tank needed to be topped up. I stopped at a shop and decided to go up a steep driveway. To my surprise the fuel bowser icon came on the screen. I decided I had better attend to the fuel tank straight away. Driving horizontally the light went off but the "Distance to empty" showed as 0 km. Upon stopping at next available fuel station I filled the tank to the guzzling noise and a bit more. It showed 60.7 L That means there was still more than 20L left in the tank but the vehicle thought it was empty. [bigsad]

[Tombie]

Firstly the Tank isn’t parallel so 1/2 isn’t half - isn’t on most vehicles.
Secondly - if you’d stopped on the flat and shut down for a while, when you restarted it would have added a few km.
There’s a hysteresis built in to stop them bouncing around.

The tank is long, thin and runs fore/aft.
Park on the steep angle and it will show a different reading for a while.

Be happy. I smacked the bottom of mine 6 months after I got it, bent the plate and dented the tank damaging the internals.
I go from full to empty on the gauge in 480km...

[letherm]

hysteresis

I thought I had a reasonably good vocabulary but you keep improving it for me. :clap2:

Martin

[Dumb Country Boy]

Nope, but I think your analysis is spot on - same observations about my MY15 D4 SDV6

Cheers


Hi all, most of you are probably aware the fuel gauge on the D4 is not accurate.
Mine says 0km to empty and there's still at least 12 litres left in the tank.....
I can pretty safely get another 100kms once the gauge indicates 0km to empty...
Also my speedo is out by approx 4km/h.

Does anyone know of a fix for these annoying problems?
Cheers
Darren

[orville]

Firstly the Tank isn’t parallel so 1/2 isn’t half - isn’t on most vehicles.
Secondly - if you’d stopped on the flat and shut down for a while, when you restarted it would have added a few km.
There’s a hysteresis built in to stop them bouncing around.

The tank is long, thin and runs fore/aft.
Park on the steep angle and it will show a different reading for a while.

Be happy. I smacked the bottom of mine 6 months after I got it, bent the plate and dented the tank damaging the internals.
I go from full to empty on the gauge in 480km...

I think I will investigate this Hysteresis further, I am not sure I understand it fully but think it is a magnetic lag in the sender. Interestingly I parked backwards into the bay with the rear up the hill, would the vehicle react to this in a short time taken to park? When I left the shop after maybe 15 minutes I decided to drive around and then up the driveway to the back of the shop which was up hill instead of entering the busy road.

So the fuel would have been at the front of the tank whilst parked and then at the back as I drove away, how quickly does the gauge react to this? I would have thought the gauge would have stopped when I parked and had this level in memory then slowly adjusted. What happens off road up hill and dale? I wonder how quickly it reacts. I also would have thought there would be a baffle to stop fuel moving quickly in the tank.

[BushDisco]

I think I will investigate this Hysteresis further, I am not sure I understand it fully but think it is a magnetic lag in the sender. Interestingly I parked backwards into the bay with the rear up the hill, would the vehicle react to this in a short time taken to park? When I left the shop after maybe 15 minutes I decided to drive around and then up the driveway to the back of the shop which was up hill instead of entering the busy road.

So the fuel would have been at the front of the tank whilst parked and then at the back as I drove away, how quickly does the gauge react to this? I would have thought the gauge would have stopped when I parked and had this level in memory then slowly adjusted. What happens off road up hill and dale? I wonder how quickly it reacts. I also would have thought there would be a baffle to stop fuel moving quickly in the tank.Resurrecting an old thread.

So about 2 months ago I disconnected the engine battery to install the full second battery kit on my my12 hse. All good from that perspective.

However I now find that the fuel guage is no longer accurate. As an example tonight the needle was near the bottom of the lcd guage, the fuel light low and orange fuel fill light had been on for a couple of days and distance to empty was approx 50k. However I could only squeeze in 49 ltrs, and that was dribbling in at the end to get that much in.

The guage now shows full, average fuel consumption via the readout is 8.2 as per normal and actual is around 10.

Before Xmas I was getting over 70ltrs into the tank when showing low fuel and over 700km to the full tank. Now I'm getting about 500k.

Any idea how to reset this guage? Note there has been no damage to fuel tank.

[Eric SDV6SE]

It's been well documented that one issue with the D4 is the relatively small diesel fuel tank capacity. As I understand it, the fuel system is a closed loop, with excess fuel supplies to the HPFP returned to tank. Therefore in order to keep the pump and system primed (this includes pump seals lubricated), there has to be a residual volume in the tank. I've read that this requires a minimum of 5-8l of diesel. Allowing for variances in use, a factor of safety and things like parking on inclines, this volume would easily increase to over 10l.

It isn't recommended to run any modern car to empty because of the complex fuel systems, especially common rail HP diesel due to risk of damage to fuel pumps etc.

I also agree that the LCD display is sometimes slow to react, but in my experience has always been accurate to within say 5-10%.

Diesel is also less dense than water and is affected by ambient temperature just like any other fuel. There is an allowable tolerance in fuel dispensers of up to 1% according to AS.

My personal experience has been when the gauge reads "empty" the usable volume is exhausted and I'm running into "reserve" capacity, or the fuel needed to prime the system. The closest I've let it go to is 20km to empty, I then managed to get close to 78l in the tank, leaving a theoretical 5l remaining. That in my view is sailing too close to the wind and risks significant fuel system damage. I now fill up as full as possible when the gauge reads empty and normally before the fuel light comes on and I have no issues. On remote trips, minimum 1 x 20l reserve at all times, preferably 2 off.

As to resetting the gauge, a hard reset after parking on a flat level surface after the tank has settled should do the trick

[dirvine]

According to my car Manual, you cannot run the D4 to empty. For my information only one day I ran the car till empty ie the computer saying "distance to empty was 0" and the fuel light came on when it said 60kms to empty. However I was able to drive another 25kms after the computer said 0 and then it went into limp mode for 3kms and then the car stopped. I filled up and the computer reset and I drove on.

[DiscoJeffster]

I have run it to zero on the computer and continued on for a while after. By the time I got to the fuel station it took 70L I think so it left about 8L remaining, or around 70km.