DTE is not very accurate

AUTickford · 22-09-2006, 11:48 AM

On my 99 v8 forte the dte computer is a real worry, i tend to look at that more than the gauge. The problem is that it goes down 20 ks sometimes to warm up then the stupid thing starts goin up. Most of the time it just goes down except on the freeway then the economy gets better. Is this normal or what. Oh yeah whats the go with that poxy beeping noise when the dte goes under 80. Is it a fuel pump saver, to stop dirt and crap being sucked off the bottom of the tank.Thats all i can think it is for.

:

Casper · 22-09-2006, 11:54 AM

The "poxy" noise that happens at 80, 40 and 20 is an "hey, you are about to run out of fuel" warning. Pretty standard on almost any car that has a DTE setup.
As for the guage going up and down, this is pretty normal. As its based on "averages" the DTE will drop when the average usage goes up. On the freeway, where fuel usage is minimal, the average consumption reduces and therefor the calculation of "average fuel use / litres left in tank" causes the DTE to actually go up. Its not unusual to drive home from Heathcote after a day of racing (huge fuel usage) and leave the track with 1/2 tank and DTE beeping and claiming less than 80kms to go... yet get home and have the DTE say 120km to go... without putting anymore fuel in.

jimt3te50 · 22-09-2006, 11:54 AM

Quote:

Originally Posted by AUTickford

On my 99 v8 forte the dte computer is a real worry, i tend to look at that more than the gauge. The problem is that it goes down 20 ks sometimes to warm up then the stupid thing starts goin up. Most of the time it just goes down except on the freeway then the economy gets better. Is this normal or what. Oh yeah whats the go with that poxy beeping noise when the dte goes under 80. Is it a fuel pump saver, to stop dirt and crap being sucked off the bottom of the tank.Thats all i can think it is for.

:

Ummm noooooo- I would say it is there to let you know you're going to run out of fuel soon and you should find a servo.

It is normal for the figure to fluctuate like that- the computer measures distance travelled for fuel used- eg no distance travelled (idling) still uses fuel but at that rate the distance remaining is depleted as you are not covering any ground. That's perfectly normal.

I love the DTE- I drive by it. I have doen a crapload of mods to my car, even run 43Lb injectors and it is still perfectly accurate.......

Allen · 22-09-2006, 11:55 AM

The distance to empty will change depending on your driving habits. If you drive along normally you will get for example 10L/100K's, but if you were then to put your foot down the instant fuel consumption will go up considerably. The DTE will change to reflect on this change. It is basically saying that if you continue to drive like this, you will only get this many k's untill you run out of fuel.

The DTE will change when the engine is cold, as it will run rich in order to warm up quicker, thus using more fuel. Once it warms up it will lean out and use less fuel.

The beeping noise is mainly just a reminder that you have an estimated 80k's until empty, so you should fill up.

Remember, it is a fairly simple computer that was built by the lowest bidder, I wouldn't place too much trust in them :P

AUTickford · 22-09-2006, 01:03 PM

What i meant was that if u let your tank get too low with an electric fuel pump it sucks off the bottom. Why else would it start doing it when theres still 80 ks left, not like your gonna run out any time soon. Maybe its for the blind people who cant c the gauge. Considering every falcon ive ever owned has had a faulty fuel fuel pump from running too low, low fuel level causes cavitation in the pump and also sand and crap goes through the pump even with the screen working properly :monkes:

MRJUCY · 22-09-2006, 02:59 PM

When you're driving around locally 80kms is a long way but if you're on a highway etc it can easy be that far between service stations so it's a fairly reasonable number.

Smoked · 22-09-2006, 04:08 PM

People on here have been known to get to 0 onthe DTE and keep going for another 25 or so Km's. On my Gas model, its accuracy is about 3/4 of All.

Mr Hardware · 22-09-2006, 04:18 PM

I had a brainwave the other night. Check me to see if I'm right.

If:
I know exactly how many litres I can fit in my tank (empty to full)
and
i reset the trip meter when i fill up to absolutely full

then

I can work out how many L/100klms I am doing by:

Adding the DTE figure to the trip meter (distance travelled)

then

I can work out how many kilometres I can expect from this current tank of fuel.

And so if i know how many litres i can fit in my tank, i can work out

Expected Kilometres / Capacity = Kilometres per litre
which can then be converted to Litres Per hundrded kilometres

AM I RITE?

Mr Hardware · 22-09-2006, 04:21 PM

So for example

Say can fit 66L into my gas tank, empty to full.

I fill up full, reset trip meter, travel for a few days

Trip meter says i've done 120klms, DTE says I have 210 left to go.

Combined total is 330klms.

So

330klms / 66L = 5klms per litre

Which is 20L/100klms

AM I RITE?

Casper · 22-09-2006, 04:29 PM

Quote:

Originally Posted by Mr Hardware

So for example

Say can fit 66L into my gas tank, empty to full.

I fill up full, reset trip meter, travel for a few days

Trip meter says i've done 120klms, DTE says I have 210 left to go.

Combined total is 330klms.

So

330klms / 66L = 5klms per litre

Which is 20L/100klms

AM I RITE?

Yep, thats basically what a DTE does. Difference is it can average out your usage as you go (city conditions, freeway conditions, hooning fun conditions) and constantly update it for you.

Mr Hardware · 22-09-2006, 04:32 PM

oh snap

im a genius lol

AUIII · 22-09-2006, 05:36 PM

Quote:

Originally Posted by Smoked

People on here have been known to get to 0 onthe DTE and keep going for another 25 or so Km's. On my Gas model, its accuracy is about 3/4 of All.

This happened to me coming back from a trip to cairns.

I was about 200 klms from Injune and there were no petrol stations until then. The DTE said I had about 300 +ks to empty I had been doing highway driving all day.
There was side trip to Carnarvon Gorge.

I did a quick calculation and worked out I had enough fuel to go to Carnarvon gorge and back then head to Injune to fill up. What I didn’t calculate was how much fuel I would chew up on the slow rocky road in to Carnarvon Gorge and back.

Once I was back on the highway the DTE showed 80klm and I had 200km to go to the next fuel station.

The DTE went up and down until 30 klms out of injune when it then flashed 0, I couldn’t believe it when I arrived at Injune, that was the most intense 30 klms I had ever driven , I had been expecting the engine to stop at any moment.

The tank took 69.5 liters when I filled up.

Mr Hardware · 22-09-2006, 05:40 PM

JC · 22-09-2006, 06:00 PM

Quote:

Originally Posted by Mr Hardware

oh snap

im a genius lol

Apparently.

bodes-sh · 22-09-2006, 06:26 PM

Quote:

Originally Posted by AUIII

This happened to me coming back from a trip to cairns.

I was about 200 klms from Injune and there were no petrol stations until then. The DTE said I had about 300 +ks to empty I had been doing highway driving all day.
There was side trip to Carnarvon Gorge.

I did a quick calculation and worked out I had enough fuel to go to Carnarvon gorge and back then head to Injune to fill up. What I didn’t calculate was how much fuel I would chew up on the slow rocky road in to Carnarvon Gorge and back.

Once I was back on the highway the DTE showed 80klm and I had 200km to go to the next fuel station.

The DTE went up and down until 30 klms out of injune when it then flashed 0, I couldn’t believe it when I arrived at Injune, that was the most intense 30 klms I had ever driven , I had been expecting the engine to stop at any moment.

The tank took 69.5 liters when I filled up.

lol thats not bad considering the manual says the tank is only 68 litres usable, well done

AUTickford · 22-09-2006, 10:33 PM

Must have the big tank bathurst option

jimt3te50 · 22-09-2006, 10:49 PM

Quote:

Originally Posted by AUIII

This happened to me coming back from a trip to cairns.

I was about 200 klms from Injune and there were no petrol stations until then. The DTE said I had about 300 +ks to empty I had been doing highway driving all day.
There was side trip to Carnarvon Gorge.

I did a quick calculation and worked out I had enough fuel to go to Carnarvon gorge and back then head to Injune to fill up. What I didn’t calculate was how much fuel I would chew up on the slow rocky road in to Carnarvon Gorge and back.

Once I was back on the highway the DTE showed 80klm and I had 200km to go to the next fuel station.

The DTE went up and down until 30 klms out of injune when it then flashed 0, I couldn’t believe it when I arrived at Injune, that was the most intense 30 klms I had ever driven , I had been expecting the engine to stop at any moment.

The tank took 69.5 liters when I filled up.

Two weeks ago I managed 72 litres in the tank- that's my best effort so far....

T3man · 22-09-2006, 10:52 PM

Quote:

Originally Posted by AUTickford

What i meant was that if u let your tank get too low with an electric fuel pump it sucks off the bottom. Why else would it start doing it when theres still 80 ks left, not like your gonna run out any time soon. Maybe its for the blind people who cant c the gauge. Considering every falcon ive ever owned has had a faulty fuel fuel pump from running too low, low fuel level causes cavitation in the pump and also sand and crap goes through the pump even with the screen working properly :monkes:

Your theory is wrong any way you want to look at it. The fuel pump pickup is in the same position in the tank regardless of the amount of fuel left. If there is crap in your tank it will be more likely to be picked up immediately after fill-up if at all because this is when any tank sediment would be disturbed.

As you have guessed the beeps are simply a low fuel warning for visually impaired people who cannot read the guage or see the red warning light clearly - very considerate of Ford to provide an aural warning don't you think?

T3man · 22-09-2006, 10:59 PM

Quote:

Originally Posted by jimt3te50

Two weeks ago I managed 72 litres in the tank- that's my best effort so far....

70.5 litres is the most I've managed to put in mine. Coming across the Hay Plains towards Hay (of all places LOL) from Balranald and the DTE was on zero when I was still 25km out of Hay. I was very glad when I saw that the first petrol station coming into town was open - don't think I would have made it to the second one.

I honestly think if you were able to put 72 litres in then the pump was out of calibration - apparently up to 25% of pumps in NSW have been found to read incorrectly according to recent tests carried out by ACA et al.

AUIII XR8 MAN · 22-09-2006, 11:09 PM

Quote:

Originally Posted by jimt3te50

Two weeks ago I managed 72 litres in the tank- that's my best effort so far....

I've done the same.

TwistedEL · 22-09-2006, 11:49 PM

Mine said 650k's on Saturday now the combined is down to about 520... so I wouldn't put too much faith into it, it seems a nice cool night makes a big difference on DTE.

**Captain Stubing** · 23-09-2006, 12:00 AM

Quote:

Originally Posted by T3man

70.5 litres is the most I've managed to put in mine. Coming across the Hay Plains towards Hay (of all places LOL) from Balranald and the DTE was on zero when I was still 25km out of Hay. I was very glad when I saw that the first petrol station coming into town was open - don't think I would have made it to the second one.

I honestly think if you were able to put 72 litres in then the pump was out of calibration - apparently up to 25% of pumps in NSW have been found to read incorrectly according to recent tests carried out by ACA et al.

If the fuel tank has a 68 litre capacity, do they include the amount of fuel you can fit into the filler pipe? You'd have to gain a few litres there, I'd bet ?

MoreHPformyXR6 · 23-09-2006, 12:17 AM

Quote:

Originally Posted by T3man

The fuel pump pickup is in the same position in the tank regardless of the amount of fuel left. If there is crap in your tank it will be more likely to be picked up immediately after fill-up if at all because this is when any tank sediment would be disturbed.

Was wondering why & I cant remeber if I read it on here or my owners manual they encourage you not to let your fuel go really low before refilling. (Apart from the obvious you might run out of juice). If you continue to let your fuel go really low the majority of the time before refilling, are you likeley to damage some components or something? Is this the reason.

:

TwistedEL · 23-09-2006, 12:23 AM

68 litres usable capacity - technically you're only meant to let the fuel pump click twice and then your there with some free space for gasses but not many people do that

RCM MasterTech · 23-09-2006, 01:14 AM

If you look at an e series wagon tank, under a 1/4 tank of gas the pump is in air, the main cause of damage to pumps is heat, and commodores are far more known for fuel pump probs than falcons, the pump runs cooler immersed in fuel than in air, thats why they say keep it above a 1/4 and the same reasoning for the warning beeps at 80ks to empty. The fluctuation with dte is quite normal, our nrma ute with the same load and 4 different drivers never varies much, no matter how you drive it because of the load. Duel fuel (not factory) cars say keep above a quarter tank cos the fuel pump runs even when on lpg.

with the plastic tanks, on a hot day I have put in 80 ltrs into the eb, and thats still only sposed to have a 68 ltr tank, expansion is an amasing thing......

As for getting 20 to 30 ks after 0 reading be glad you dont drive a vectra, seen plenty of them out of fuel with 40 to 50 ks to empty on dte, and that 20 to 30 ks is pump cooling fuel so less risk of damage. If you got dirt in your tank, its gonna pick up anyways, as the fuel pickup is at the lowest point in the tank.

The fuel pump will also run hotter if its working harder, blocked filters are a prime cause of fuel pump failure.

kryzak260 · 23-09-2006, 01:42 AM

I found in my car that if you put the car in neutral and roll backwards, the DTE climbs up lol. I did that 200KMs into a trip about 9 months ago when i had to stop at some roadworks. Put the car into neutral and rolled back 30 or 40 meters and i gained 30 or 40 kms on the DTE. Wasnt a coincidence either, because i have done it once since.

I imagine it is a bug in the code that calculates the figures (to do with negative speed or something)...

XR6Stu · 23-09-2006, 09:38 AM

I hate putting fuel in my car. As a result I regularly run around close top zero, and have been known to drive around for a day or more on zero on the DTE. Most Ive ever been able to get is a tiny bit over 50 k's, 5o.6 or something, then ran out of fuel. I should try to find me a "bathurst big tank option fuel tank" then hey? I love the people who ask for advice or opinions, then scoff at them or the people giving them. Alternatly, my old mans AU one tonner, you get to about 20k's till empty, and your sitting on the side of the road wondering what happened.

Smoked · 23-09-2006, 11:07 AM

I managed to get 78 litres into my GAS tank, only supposed to be 73 usable. Checked my AFL, not busted, just a cold night.

MoreHPformyXR6 · 23-09-2006, 01:09 PM

Quote:

Originally Posted by RCM MasterTech

If you look at an e series wagon tank, under a 1/4 tank of gas the pump is in air, the main cause of damage to pumps is heat, and commodores are far more known for fuel pump probs than falcons, the pump runs cooler immersed in fuel than in air, thats why they say keep it above a 1/4 and the same reasoning for the warning beeps at 80ks to empty. The fluctuation with dte is quite normal, our nrma ute with the same load and 4 different drivers never varies much, no matter how you drive it because of the load. Duel fuel (not factory) cars say keep above a quarter tank cos the fuel pump runs even when on lpg.

with the plastic tanks, on a hot day I have put in 80 ltrs into the eb, and thats still only sposed to have a 68 ltr tank, expansion is an amasing thing......

As for getting 20 to 30 ks after 0 reading be glad you dont drive a vectra, seen plenty of them out of fuel with 40 to 50 ks to empty on dte, and that 20 to 30 ks is pump cooling fuel so less risk of damage. If you got dirt in your tank, its gonna pick up anyways, as the fuel pickup is at the lowest point in the tank.

The fuel pump will also run hotter if its working harder, blocked filters are a prime cause of fuel pump failure.

Thank's for the explanation. So bottom line running fuel very low all the time creates more heat on fuel pump. Assuming your fuel filter is in good condition etc. You would be unlucky to have fuel pump faliure on a Falcon (petrol model) caused by running the tank low? No other factors involved eg blocked fuel filter.

V8falcons · 23-09-2006, 10:04 PM

my wagon DTE is way out,ran out twice at 60kDTE,I found its only accurate in my car when I fill the tank full ,and not small top ups along the way,its starting to **** me as it was today 324 when I got to work this morning,then I go up the shop 3 hrs latter an the buzzers going off and there 53k DTE......
Allthough I never really park my car facing down the car park as I did today so this may have had something to do with it.
when its full to the brim the gauge is full, empty,full, empty and so on for about 50ks,getting a new pump and sender unit in the next couple of weeks