The DTE Is Just An Estimate... and Varies

[jeff_h]

I noted in another post that I've seen my Trip1 elapsed miles (which I reset each fill-up) combine with my DTE to be over 700 miles on a couple occcasions... and as the tank burns through, it gets more toward reality and settles around 600 or so for the tank. Last fill-up was 601 miles, the one before that 591, the one before that 594.

 

So today I took some pics of the Trip1 elapsed along with the DTE (about 100 miles in is when it seems to feel the most ambitious, for whatever reason) - and as has been discussed, the DTE is based on your recent MPG history. In the manual for my 2010 it said it was based on the past 500 miles, but I don't see a number stated in the 2013 manual. But from the below, I tend to think the DTE number is calculated based on the past X miles but is weighted heavily on the very recent MPG. My example is below.

 

With odometer at 13,926 miles - Trip 1 had gone 121 miles,

 

...and has 593 miles left (total of 714 miles) which I think is a big number by any account.

 

But then, after going down a long downhill with a lot of regen braking, with odometer at 13,930 miles - Trip 1 had gone 125 miles,

 

...and has 647 miles left (total of 772 miles) which is a LOT more, especially after just 4 miles later!

Edited May 29, 2013 by jeff_h

[hybridbear]

Very interesting! I agree that caution needs to be exercised when it comes to the DTE numbers. I prefer using the gallons used according to my trip meter that is reset with each fill-up and using the FLPM in Engineering Test Mode

[aaronj1159]

Yeah, on my trip back from WV over the weekend, my DTE said 140 miles. 20 minutes later (after another 20 miles as well) the DTE readout said 171.

[dalesky]

Very interesting! I agree that caution needs to be exercised when it comes to the DTE numbers. I prefer using the gallons used according to my trip meter that is reset with each fill-up and using the FLPM in Engineering Test Mode

Then there's always the old fuel gauge, which shows remaining gas. I know, old fashioned, but it works. I used to very occasionally run my previous car to within a gallon of empty. Not on purpose, and it made me very nervous. Point is that the estimated mileage to empty reading was very accurate. The way that one worked was that it would readjust the estimate according to the instant MPG. As I went from city to highway driving, then hit the sweet spot on the cruise, it would continue to climb.

 

On the Fusion I am still not used to changing the info shown on the left side, and cannot get to things like the DTE, then back to the display I prefer most of the time. Ah, the joys of having too much tech at times.

Edited May 30, 2013 by dalesky

[fusionTX]

That's kind of scary when you think about it. I do think it gets closer to reality when you are running out of fuel, but I do remember it hitting zero before I expected during my Florida trip. I will keep a closer eye on it in the future.

[acdii]

I had a crown Vic that could go 30 miles past zero. It was not very accurate.

[B25Nut]

 

 

On the Fusion I am still not used to changing the info shown on the left side, and cannot get to things like the DTE, then back to the display I prefer most of the time. Ah, the joys of having too much tech at times.

 

I have My View set for DTE and Engine Temp. 98% of the time I display Engage, but it only takes pressing the down button twice to get to My View to see DTE. I rarely use most of the tech features that are available. Having Sync read a text message to me earlier this week just by pushing one button made me feel Iike Capt. Kirk on the Enterprise.

[jeff_h]

 

I have My View set for DTE and Engine Temp. 98% of the time I display Engage, but it only takes pressing the down button twice to get to My View to see DTE. I rarely use most of the tech features that are available. Having Sync read a text message to me earlier this week just by pushing one button made me feel Iike Capt. Kirk on the Enterprise.

 

This is the same as I do, which is keep it on Engage and then arrow down twice to check DTE. However I like the feature of sync reading text messages, my wife and I like sending goofy texts and listen to the sync lady speak them out. And BTW, if someone sends a :) icon, the sync lady pronounces it out as "happy face" and I think the :( she pronounces out as "sad happy face"...

 

But back to the DTE, one day later and it's back toward reality, I think the total is now around 620.

[dalesky]

 

I have My View set for DTE and Engine Temp. 98% of the time I display Engage, but it only takes pressing the down button twice to get to My View to see DTE. I rarely use most of the tech features that are available. Having Sync read a text message to me earlier this week just by pushing one button made me feel Iike Capt. Kirk on the Enterprise.

appreciate the info Nut

[expresspotato]

I had a crown Vic that could go 30 miles past zero. It was not very accurate.

Can't these cars go ~60 Miles past zero?

[jeff_h]

Can't these cars go ~60 Miles past zero?

 

Potentially, though I don't want to run it dry... farthest I've gone past 0 was 30 miles and it took 13.2 gallons to refill the 13.5 gallon tank.

[acdii]

Can't these cars go ~60 Miles past zero?

Considering my first Vic smoked the trunk wiring from running the pump dry, did not want to take that risk again.

[fusionTX]

Can't these cars go ~60 Miles past zero?

I usually go 20 past zero. In city driving, 20 past zero still leaves me with a gallon of gas. So yes, theoretically you could go 60 miles past zero under these conditions, assuming your MPG average is over 40 MPG.

 

Going 20 past DTE while on a road trip at high speeds can be cutting it very close.

[jeff_h]

OK so here is how that tank ended up. I checked status last night and I had gone 420 miles and it showed 230 miles DTE. I knew I was going to the client site today so with going there and also to the office, it would be about a 200 mile day.

 

It didn't start well, steady rain and heavy traffic and 5-car accident on I-95, so once again I took 'the long way' and even though a couple weeks ago I got 57 MPG going that way, today I found that the new "Battle of Manassas" is one with a whole lot of traffic lights and stop-n-go (so I guess I was standing there like Stonewall Jackson). So it was a bad start to the day and 2hr 50min to get to the office, with MPG far less than the 57 I got a couple weeks prior.

 

So then after just 30 minutes at the office, it was on to the client site (up near fastronaut's place), and unfortunately I had a scheduled meeting so couldn't wait until rush hour was all done... turns out traffic was just slow enough to yield good MPG, but not so slow as to keep the HVB SOC around 15% where it cycles on and off every 30 seconds as you inch along in traffic (so for those that spend miles in the city and get so-so MPG, this bud's for you), I think that was one of the causes to the lower MPG above since it was endless ICE cycling to get the SOC just above minimum.. but anyway, on the second leg of the day with the rain NOT falling and traffic manageable, this was a much better MPG trip! (1hr 40 min)

 

Then the way back from client site also yielded good MPG, a nice and smooth ride with 100% brake score. And under an hour!

 

So then it was time for the last leg of the day to head home (60 miles), and according to the display I should have just enough to get home - here's the DTE and Trip Summary at that point, with 60 to go.

 

Well I made it, went 4 miles past 0 DTE (as opposed to 11 to spare at the start of last leg, but it was pouring rain and hydroplaning, etc), here is how it looked when I got to the gas pump, which is a far cry from the 720 or 772 or whatever huge DTE number I got the other day.

 

Above display said 12.28 gallons and 51.5 MPG when I got to the pump... actual numbers from the fill-up were 12.481 gallons and 50.71 MPG. Not as good as the display, but I've always found it to be a tad optimistic. Traffic still stunk coming home, 2hr 10min since there was again pouring rain (49.3 MPG), but that's why I've been adamant about getting just the car I want since I spend so much darn time in it.

 

So then once filled up, let's see how far it says I can go on THIS tank. We shall see....

 

[dalesky]

Really nice report! Gives me something to shoot for. I drive a lot of short trips and am very happy when I achieve for short distances. Getting better at being a more efficient driver, but have a ways to go. Must be doing somethings right, since my second tank (today, just. Over 4 weeks) was still at 1/4 full.

[rico567]

After experiences with two cars with a DTE readout (neither of them FFHs), I am very cautious about them, particularly as the tank gets low . Our SAAB DTE drops like a stone after it gets below 100 mi. We were car-sitting an '09 Hyundai Santa Fe for relatives deployed overseas, and that thing was completely untrustworthy, got to the point where I wouldn't even look at it.

[hybridbear]

One word of caution about going too far past 0 on the DTE because the trip meter shows you haven't used 13.5 gallons is that it seems that we aren't filling our tanks all the way. On the C-Max Hybrid forum most of their results show that when their DTE hits 0 ppl are putting in about 13.25 gallons. That means the DTE hits 0 in the C-Max with only 1/4 gallon remaining assuming that the maximum fuel they can put in is 13.5 gallons. In our cars we've seen the DTE hit 0 with the car only showing 11-12.5 gallons used and then all we can put in is 11-12.5 gallons. This makes me think that the design of the FFH tank/fuel inlet is such that the pump clicks off early before it is actually full. C-Max owners have reported having fuel spill over if they do more clicks than the 2 the OM recommends. In our cars I've added 2+ gallons more after the first click without the fuel level going over. This makes me think it's a design difference causing us to never get our tanks actually full, which then leads to less range and more trips to the gas station. It appears that the fuel enters the tank in the front left corner, this means that parking uphill should allow more fuel to go into the tank than parking downhill. I want to try this more at my next fill up. The problem is that we only buy gas about once every 2-3 weeks now so it's a rare occurrence for me to go to the gas station

[dalesky]

The idea of parking uphill/downhill is interesting. I haven't seen any stations that aren't level tho, perhaps because of the issue of over filling a tank. I believe the "solution" to this issue of when will you run out of gas is to fill it up at around the 1/4 level, and not try to push it. There may be times, when on a trip for example, that you don't know just how far a station is, but that can be remedied by using nav either on the car or on the phone. I simply don't like the feeling of not knowing how much further I can go before empty. I recall the last time it happened to me, I literally rolled into the station with the engine not running. It was that close. That was also well more than 30 years ago.

Suggestion- when approaching what you think is the full level while fueling, slow down the delivery of gasoline sharply, and see if that results in a truly full tank. Can't hurt.

[jeff_h]

In our cars I've added 2+ gallons more after the first click without the fuel level going over.

 

Not always, as the last time I got gas (not yesterday, the time before that) I kept topping off since it does get difficult to complete the fill-up, as you noted. I stopped clicking when gas came out of the filler tube, so I said 'yep it's full now'... though I didn't do that yesterday but came close, so if I really wanted I might have gotten another .2 or .3 gallons in there, but I didn't want to make a habit of watching my money flow onto the ground and gas onto the paint, so that one time was it for topping off until it could take no more.

 

Added - was parked at the pump slightly uphill... not any significant grade, but enough to assist with drainage, like the crown in a road. Also, when it first clicked I took the nozzle fully out, then clicked 2-3 more times, nozzle back out, then 3-4 more clicks.

Edited June 4, 2013 by jeff_h

[hybridbear]

The idea of parking uphill/downhill is interesting. I haven't seen any stations that aren't level tho, perhaps because of the issue of over filling a tank. I believe the "solution" to this issue of when will you run out of gas is to fill it up at around the 1/4 level, and not try to push it. There may be times, when on a trip for example, that you don't know just how far a station is, but that can be remedied by using nav either on the car or on the phone. I simply don't like the feeling of not knowing how much further I can go before empty. I recall the last time it happened to me, I literally rolled into the station with the engine not running. It was that close. That was also well more than 30 years ago.

Suggestion- when approaching what you think is the full level while fueling, slow down the delivery of gasoline sharply, and see if that results in a truly full tank. Can't hurt.

We aren't talking about major grades, just slight inclines. I've also always filled up on the slowest setting. Maybe next time I'll try filling faster and then slow down

[jeff_h]

We aren't talking about major grades, just slight inclines. I've also always filled up on the slowest setting. Maybe next time I'll try filling faster and then slow down

 

Exactly - I think if you look closely, you may find that many pumps are on a grade just slight enough to have rain water drain off, yet not to the extent that a gas spill would quickly run all over the place. I've noticed several of my area stations seem to be this way, and for the sake of refueling as long as the grade is enough for the air to escape then I suppose that's enough.

[acdii]

Most stations I go to have a concrete slab where the pumps are and asphalt surrounding it. The Concrete is level, but the asphalt slopes away, so I park the car to the front wheels are on the asphalt which will put the nose down just a little,