[ghodlur]

During the second service of my Fiesta I had pointed out to the service guys about the abnormal Distance To Empty (DTE) values and was told that the DTE was functioning normally. I had requested from Ford a writeup of the DTE and what factors nomally affect the DTE values to which Ford sent a pdf file highlighting the FAQ's. Pls find ths attached file for reference.

Some of the answers are debatable. Would request Fiestians to read the document and comment.

[greenhorn]

Looks good enough. The system is not psychic, and works well based on its constraints.

[Gilead]

Which answers are debatable? I found all the responses to be good enough. Like they say, it's a running average fuel economy indicator and it's bound to vary depending on the conditions. I have found my DTE to be reasonably accurate, but I don't depend on it for FE calculations.

[SirAlec]

I don't trust this digital thingy. Its just there as a fancy item, a show piece, just to make you happy that its there. They are never accurate.

JC of Top Gear fame, tried this on a V8 turbo Jaguar. He drove it in one of his challenge like crazy to test its mileage. A challenge he thought is rubbish and could not be achieved in real world, hence he drove it like crazy so he runs out of fuel early and go home.

Not only he reached his destination but there was diesel left for another 100 or so miles.

Always use tankful to tankful theory and note down the oddo readings. I always do this and never have failed once.

[benbsb29]

Beats me. I didnt find any new information in there that we already didnt know about. But it was nice of them to reply to the query with a proper document.

[McLaren Rulez]

As long as the DTE doesn't overestimate the distance that can be covered, it should be alright. The problems start if the DTE tells you can do ten kilometers only for you to run out of fuel in five.

[aargee]

I found nothing new in the doco that is not discussed in the forums; IMO, Ford has answered everything crystal clear & I don't see any answers to be debated.

[echo77]

Originally Posted by McLaren Rulez

As long as the DTE doesn't overestimate the distance that can be covered, it should be alright. The problems start if the DTE tells you can do ten kilometers only for you to run out of fuel in five.

I'd rather refill when DTE tells 50km to go, which means there would be at least 3-5 litres of fuel left.

If DTE says 10km to go its like 1/2 - 1 litre of fuel left, and there's no guarantee how long you can go on.

[rpmx1000]

The DTE is a beautiful piece of work. Like most other members, don't trust it too much. But it has never failed as a warning indicator of when to fill up. And Ford's done a good thing by sending this dummies guide to the DTE . Shows the extent to which they have chosen to care. Good job by Ford and it will save as a ready reference to anyone who wants to really understand.

[sanjayc]

The document if clear enough...few of my doubts which I was having after my last tank refill gets clarified.

I did a 10litre topup when the DTE was running dangerously low (showing 10 Kms, with fuel guage needle below the red mark) at the nearest avlbl bunk, which I do not trust, just to ensure I do not run out of gas. I immediately started noticing erratic jumps in the DTE readings (e.g, when idling at signals it will show 60, then suddenly jump to 90, and come back to 70, all within a few seconds)...remember Gilead also posting such experience somewhere here..Next day post doing a full tank, within 2-3 days, the erratic readings has settled down to a more trustworthy level.

The 500Kms history seems to be true..earlier, after 5K kms of highway driving where I was getting >12 FE, now it has settled down to around 9ish for the last 700+ in-city driving.

[RGK]

Originally Posted by SirAlec

I don't trust this digital thingy. Its just there as a fancy item, a show piece, just to make you happy that its there. They are never accurate.

Always use tankful to tankful theory and note down the oddo readings. I always do this and never have failed once.

Absolutely. DTE can be taken as a warning for refueling. If DTE is accurate in some cases then well and good. thats all.

[Rehaan]

Originally Posted by ghodlur

...I had pointed out to the service guys about the abnormal Distance To Empty (DTE) values and was told that the DTE was functioning normally. ...

What exactly were these abnormal values in your case?


I think thats a very comprehensive FAQ - and nice that Ford actually sent it to you.

As for DTE - you have to understand that it nothing more than an ESTIMATION using data from recent driving habits.

The same way, suppose you take a dog for a walk - do you know how much water its gonna drink after that? You can only guess, as it depends on: how hot it is outside, how much the dog walked, how fast it walked/ran, how much rest it got in between etc.


It is possible (as also mentioned in the FAQ) that if one of your sensors isn't working properly, the DTE could we VERY incorrect.

cya
R

[ghodlur]

@rehaan,

I have been a sedate driver and my driving habits have hardly changed since my M-800 days. The real cause of concern sometimes is that there is an useful gadget called DTE and I am unable to use it to full utlilization. The abnormal readings which I had referred to Ford during the service was like starting the car at 388 on DTE and travelling a distance of 23 kms at avg speed of 60 kmph and the DTE at the destination reads 256. Again starting the car the DTE now reads 350 and upon the same distance travelled the DTE reads again 250. This huge variation normally starts when the tank reached half and towards the empty. When i park my car upslope the DTE increases, but on downslope the DTE reduces. I am unable to get a somewhat close picture of DTE.

[nairrk]

Besides DTE the vehicle also equipped with a Low Fuel Warning Light. So once the light comes on, be prepare for refuelling. As such no worry about DTE which is just a rough calculation. I have seen in my car, most of the time when the DTE figure show around 80/85, I used to get the fuel warning light also comes up.
Low Fuel warning light is equipped in almost all cars and the car will have about 5 to 7 litre of fuel left when the warning light comes on? So imo, better follow this than worrying about DTE??

[greenhorn]

ghodlur, if you've used regular fuel gauges , you'd have noticed that the position of the fuel gauge changes if you park on a slope. I suppose this is due to the fuel level transducer. When you park on a slope, the fuel tilts to one side, and consequently, the reading will also be different.

The behaviour of the DTE is consistent with the way ford has explained it. Like i said before, it cannot be psychic. It does its job based on what information it has. You appear to be quite demanding

To understand how it works, think about how it works

Inputs available =
current fuel level
Instantaneous fuel consumption
Average previous Fuel consumption for the last 500 km ( or from the behaviour mentioned, I'm beginning to wonder if this is being retained in memory. Would like other fiesta owners to comment)

How would you calculate it ?

If this is beyond your capacity, then do not try to make sense of it at all. Just think of it as an imperfect black box