When Does the Car Actually Run Out of Gas?

[Oman]

I can't speak to how Toyota does it but the FFH will refuse to drive in EV after the HVB drops to a certain level. Turn the car off and on and you can go again for just a little bit. Repeat a few times and the HVB will drop to a point where the car will not switch at all to EV mode. At this point there should still be enough to get the ICE running again but no one can guarantee that. The computer won't let the HVB drain to a point where the cells would be damaged (this can only really be done by storage loss or a malfunction). If there isn't enough juice to get the ICE running you have to have the car towed to the dealer where they can put a special charger on the HVB to bring it up to a point where the ICE can be started.

 

No tow truck or the like can "jump" the HVB and that is the only thing that can start the ICE. There have been cases of the 12V battery going out and that can easily be jumped. The 12V system has to be "alive" to allow the high voltage system to work.

 

Jon

 

 

I would think (don't know for sure thank goodness) that both Toyota & Ford would shut the car down if the high voltage battery got so low it might cause damage to itself, never heard of a HVB being jumped. As for running the tank so low 'sludge' is sucked in isn't the fuel pickup near low point in the tank that & the sucking the pump does would pick up any crap in the tank no mater the fuel level - I can see the lack of fuel pump cooling being an issue if low fuel, but this time of year your probably okay unless on a road trip.

[oldschool1962]

For what it's worth....I can't see the value in playing nothing more than Russuian Roulette with the gas gauge. Like some have mentioned, there's just too much that can happen and cause you to damage the vehicle...... damage to the fuel pump, tank debris and no matter how new or old the car si it can and will be present. Doesn't matter if you buy from the cheapest or the most expensive of stations.....their tanks are what causes the issues.

 

Running out of gas sucks. Plain and simple. It's one thing to be new out in the world, trying to make ends meet and squeezing just hard enough to make it to work and back on fumes are days I am so glad are more than 25 years behind me. But.......... given the cost of the FFH I can't believe there are too many out there that are in this situation and as far as a thrill.......just stand on it and negotiate a couple ramp curves at 55-65mph.....now that a thrill. Firm believer that if the tank gets to 1/4 full...... fill it up. Just feel good about having 176 miles to E when it's at a 1/4 tank.

[GrySql]

This is a duplicate post I made in the 600 mile topic, thought I'd move it here where it makes sense.

 

Today I put 13.341 in my tank. Hermans says this is normal for him, not for me though.

Driving yesterday my 'low fuel' light came on at about 8 miles from home, I went home.

This morning with a cold car from being parked overnight, I EV'd the 1-1/2 blocks from my garage to my normal gas station, set the handle on slow/low fill and stood there - and stood there.

I began getting nervous, I'd only driven about 8 miles on the low fuel alert and as it passed 12 gallons I grabbed the handle and continued the slow fill.

Finally it clicked off at 13.34, with no extra clicks - very different!

 

This has never happened before, normally it's a battle to get 10-11 gallons in this car, I use 3 clicks at every fill, which the OM states is fine.

One time I was able to add 3.5gal of gas from the first click.

 

Could the PCM update have anything to do with this? Probably not.

 

What really worries me is that prior to this the low fuel alert would come on and indicate 40-50 DTE, not this time, I went less than 10 miles from the 'Low Fuel' alert and it was DRY.

I better keep my eye on this.

 

Edit: Yes, we have expensive gas prices...

[hermans]

What I meant was that I normally able to fill my tank. I check the fill against how many gallons was still in the tank before the fill.

 

You're paying about $3.74 a gallon for gas. Where I'm at it's about $3.54. In Ohio last week it was $3.18.

Edited August 19, 2013 by hermans

[acdii]

This is a duplicate post I made in the 600 mile topic, thought I'd move it here where it makes sense.

 

Today I put 13.341 in my tank. Hermans says this is normal for him, not for me though.

Driving yesterday my 'low fuel' light came on at about 8 miles from home, I went home.

This morning with a cold car from being parked overnight, I EV'd the 1-1/2 blocks from my garage to my normal gas station, set the handle on slow/low fill and stood there - and stood there.

I began getting nervous, I'd only driven about 8 miles on the low fuel alert and as it passed 12 gallons I grabbed the handle and continued the slow fill.

Finally it clicked off at 13.34, with no extra clicks - very different!

 

This has never happened before, normally it's a battle to get 10-11 gallons in this car, I use 3 clicks at every fill, which the OM states is fine.

One time I was able to add 3.5gal of gas from the first click.

 

Could the PCM update have anything to do with this? Probably not.

 

What really worries me is that prior to this the low fuel alert would come on and indicate 40-50 DTE, not this time, I went less than 10 miles from the 'Low Fuel' alert and it was DRY.

I better keep my eye on this.

 

Edit: Yes, we have expensive gas prices...

 

 

Makes me wonder if having a cold tank has anything to do with it. Since you had no ICE action, no fuel was pumped, no evap was used, and it would have been ambient temps in the tank as opposed to heated up from driving and fuel being moved through it.

[GrySql]

 

 

Makes me wonder if having a cold tank has anything to do with it. Since you had no ICE action, no fuel was pumped, no evap was used, and it would have been ambient temps in the tank as opposed to heated up from driving and fuel being moved through it.

Okay a cold tank could explain the ease of fill, which normally has always been a hot fill, and a crap shoot, one time easy the next I put 3+ gallons more in after 3 clicks.

Like you, unless traveling, I use the same two gas stations.

 

The part that confuses me is the DTE, less than 10 miles after the 'low fuel' alert I filled it to absolute capacity.

Before this I have run 10 miles past DTE (which showed 40-50 miles DTE when the light came on) and only put in 12.5 gal, the most ever.

This time, it dropped so fast that I'd have run out of gas in another few miles after the low fuel light came on - that is noticeably different that ever before.

 

Whatever the reason, I am not chancing a low fuel situation again.

[acdii]

Okay a cold tank could explain the ease of fill, which normally has always been a hot fill, and a crap shoot, one time easy the next I put 3+ gallons more in after 3 clicks.

Like you, unless traveling, I use the same two gas stations.

 

The part that confuses me is the DTE, less than 10 miles after the 'low fuel' alert I filled it to absolute capacity.

Before this I have run 10 miles past DTE (which showed 40-50 miles DTE when the light came on) and only put in 12.5 gal, the most ever.

This time, it dropped so fast that I'd have run out of gas in another few miles after the low fuel light came on - that is noticeably different that ever before.

 

Whatever the reason, I am not chancing a low fuel situation again.

I noticed that too. One moment DTE showed me well over 50 miles, then a short time later, DING low fuel, and the DTE was cut in half, yet fuel used was only a little over 10 gallons. I leave very little faith in that DTE readout and just fill when its around 1/4 tank instead.

[GrySql]

I leave very little faith in that DTE readout and just fill when its around 1/4 tank instead.

Amen...

[hybridbear]

I have more faith in the DTE readout than reasoning "my gallons used only shows 10.5 so that means I have 3 gallons left". I do agree though that the DTE hits 0 when there's still enough fuel to drive at least 20 miles in the city (i.e. about 1/2 gallon). Having the DTE hit 0 miles with 1/2 gallon in the tank wouldn't be out of line with what I've seen in other cars I've owned.

Edited August 19, 2013 by hybridbear

[GrySql]

All my many Fords have always had ample fuel (2-3 gallons) after the low fuel light came on, I got used to that.

Up until now, I felt the same way with this FFH, or at least it seemed very similar.

Yesterdays 'light comes on', drive 8 miles and fill the tank to near capacity was a new thrill.

 

Ah, this car is full of fun techno tricks, gotta love it!

It keeps showing me that it likes me but doesn't want to be taken for granted.....

Like someone else I live with. :kiss:

[MaineFusion]

How much fuel can we actually put in and use in the 2013 FFH? The most I've been able to put in is just over 11gal. From what I've read, the 2013 FFH has a 12.5 gal tank and would love to be able to at least use 11.5 gal of that capacity reliably.

[hermans]

How much fuel can we actually put in and use in the 2013 FFH? The most I've been able to put in is just over 11gal. From what I've read, the 2013 FFH has a 12.5 gal tank and would love to be able to at least use 11.5 gal of that capacity reliably.

As I posted earlier.....I have used 13.4 gallons of a 13.5 gallon tank. All of the specs and literature show a 13.5 tank...

[dalesky]

For me, the point of when it is empty is moot, since I start getting nervous with any car at the 1/4 or below level. I rarely if even get to the point where I see a warning, and if traveling long distances do my best to plan fuel stops for efficiency and to avoid having to worry. I have run out of gas in my life, and it's not an enjoyable thing to do, so I try to keep that in mind.

[MaineFusion]

As I posted earlier.....I have used 13.4 gallons of a 13.5 gallon tank. All of the specs and literature show a 13.5 tank...

Yep page 306 of the owner's manual says 13.5gal. I don't know where I got the 12.5gal number from. Now to figure out why even when I'm down to zero miles remaining I can only put in 11 gal. :headscratch:

 

If I could reliably use at least 12 gal I could regularly go over 600mi per tank and best of all would only need to fill up once every two weeks.

 

Anyone have a diagram of what the fuel tank and fueling pipe look at? I want to figure out if how level my FFH is when fueling makes a difference.

[GrySql]

Now to figure out why even when I'm down to zero miles remaining I can only put in 11 gal. :headscratch:

Yes, that is exactly how I felt until yesterday. Although, I did get 12+ gallons in it once or twice before.

 

As for a fuel tank and fill schematic it would probably be easiest to use the Ford Parts website, type in your VIN and look at Air & Fuel Delivery>Fuel Storage.

There are pictures there of the whole system, by parts.

Edited August 20, 2013 by GrySql

[acdii]

Point I was trying to make, my drive home is between 34 and 44 miles depending on if I drop off/pick up the kids, and or drop off/pickup the wife at her office. When I leave the office with 1/4 tank and halfway home suddenly down to 29 miles to empty, with only showing 10 gallons used out of a 13 gallon tank, then fill with 11.1 gallons, it makes one go, umm cant trust the fuel gauge. Since then I dont go below a 1/4 tank.

[MaineFusion]

Point I was trying to make, my drive home is between 34 and 44 miles depending on if I drop off/pick up the kids, and or drop off/pickup the wife at her office. When I leave the office with 1/4 tank and halfway home suddenly down to 29 miles to empty, with only showing 10 gallons used out of a 13 gallon tank, then fill with 11.1 gallons, it makes one go, umm cant trust the fuel gauge. Since then I dont go below a 1/4 tank.

If I fill up at the same pump every time, which is pretty easy for me to do, my fuel gauge gallons used and the pump's gallons pumped are very similar. What I have found, however, is that gas pumps at different gas stations have more sensitive cut off triggers than others. I almost think too fast of a pump speed combined with not quite right nozzle position causes some pumps to be tripped prematurely.

 

The pump that gave me the most gas (well outside of my normal travel area) had a rubber boot that made a complete vapor seal around the fueling port. None of the pumps in my area have more than token vapor guards on them.

[corncobs]

If I fill up at the same pump every time, which is pretty easy for me to do, my fuel gauge gallons used and the pump's gallons pumped are very similar. What I have found, however, is that gas pumps at different gas stations have more sensitive cut off triggers than others. I almost think too fast of a pump speed combined with not quite right nozzle position causes some pumps to be tripped prematurely.

 

The pump that gave me the most gas (well outside of my normal travel area) had a rubber boot that made a complete vapor seal around the fueling port. None of the pumps in my area have more than token vapor guards on them.

 

I think you are on to something here! I noticed the same thing with my previous fill up when the first click came after 1.1 gal more than what trip 1 told me and it the same rubber boot.

When filling up at my local gas station the first click is usually only .3 - .5 gal past the trip 1.

[MaineFusion]

I keep observing something interesting when I fill up. It seems, that the gas gauge and distance to empty calculations aren't properly calibrated for the shape of the fuel tank. It is almost like the fuel gauge measures the tank as if it is a cube rather than being calibrated to deal with the odd shape of the tank. This is an age old issue with fuel tanks and something that one would think Ford would have addressed with the FFH.

 

For instance, when I filled up today if the gauge was accurately calibrated, when I filled up today it would have measured the tank as having 11.5 gal of usable gas based on where it will hit 0 DTE. Assuming it used my lifetime fuel economy (45.4 mpg) to predict DTE, it would have given me 522 mi DTE. Instead it displayed over 700 mi DTE. On my way home yesterday, it predicted over 160mi DTE, which should have given me enough distance to drive home from work (47mi) yesterday and then complete a round trip commute today (94 mi). However, when I got to work this morning, I only had 7mi DTE, even though I had gotten 53mpg coming home last night and 54mpg going to work this morning.

 

The solution to this is for Ford to reprogram the fuel gauge to account for the uneven shape of the tank. Where this would be helpful is with planning where to fuel up on long trips. Obviously, it would still have to make assumptions based on either lifetime fuel economy or a moving average based on the past x miles of driving.

[lolder]

What was the gauge actually showing for fuel level at these various points? For some reason, the initial 700 mile reading was certainly incorrect ( for the gen II FFH ). The DTE will increasingly approach the correct value as you approach empty as that part of the algorythm becomes the most important. What was the fuel level at the 7 m DTE?

If a figure like 700 appears again on fill-up, take it to the dealer. I'm sure the shape of the tank is compensated for and has nothing to do with the problem.

[MaineFusion]

What was the gauge actually showing for fuel level at these various points? For some reason, the initial 700 mile reading was certainly incorrect ( for the gen II FFH ). The DTE will increasingly approach the correct value as you approach empty as that part of the algorythm becomes the most important. What was the fuel level at the 7 m DTE?

If a figure like 700 appears again on fill-up, take it to the dealer. I'm sure the shape of the tank is compensated for and has nothing to do with the problem.

 

I think you are giving the algorithm too much credit. I haven't mapped out gauge levels DTE at various points, but it is something that could be done after each commute. I'm pretty sure that the fuel gauge is behaving like fuel most fuel gauges and is not compensating for irregular shape of the fuel tank instead, it is just working on a linear graph.

 

What would be interesting for a number of us to map out how many gallons used, and DTE compared to the fuel gauge levels to see if there is a trend. My gut feeling is we will find that initially (e.g. first 50mi) the gauge and DTE will drop fairly quickly, and then their drop will slow substantially until we hit somewhere around the 1/2 tank mark. Then the final 1/4 tank we will drop very rapidly again.

 

BTW: At 7mi DTE the gauge shows below empty.

[GrySql]

Since that last weird tank fill with 13.34 gallons I've driven 84 miles and the fuel gauge is still above the Full mark, it hasn't budged. :headscratch:

My DTE says 465 miles and my Trip Display says I'm getting <28mpg's on this tank.

A very interesting algorithm indeed. This has all started happening since the PCM re-calibration a week ago.

 

I have an appointment next week at the Dealer, something needs fixing, or re-fixing.

[MaineFusion]

So according to @FordService tweets via this post, DTE is based on the amount of fuel the car thinks is in the tank, minus reserve capacity times the average MPG for last 500 miles.

 

When I filled up this last time it said I had 7mi DTE and I was able to add 11.5 gal. Upon filling up it said I had over 700mi DTE. That would mean I'd either have to have 13.2 gal of usable fuel, which I don't, or I'd have to get 61mpg average for the tank. Today before heading out, I took a photo of my DTE and Trip 1. My DTE was 638mi with me having used 0.85 of the 11.5gal in put in yesterday. Given my current 500 mi average of about 53mpg, and the fact that I only have around 10.65 gal remaining of usable fuel (11.5-0.85) the display should be showing a DTE of around 565mi. Basically, the display is currently over stating my range by 13%.

 

 

[lolder]

When software updates are done, frequently many calculations are reset including the DTE. In the Gen I FFH, fuel quantity is measured to 0.1 % such as 99.9% - 00.0%. The DTE algorythm in that FFH is based on the last 500 miles mpg to reach zero DTE at about 1 gal. remaining in the tank. The "catch-up" part of the algorythm starts working when you fill the tank and start to get significantly different mpg than the previous 500 miles. If you start getting significant deviation near 0 DTE, the DTE can chang at least from about 1/2 to 2 times the actual miles driven so that you arrive at zero with some reserve. Of course it also looks at the fuel quantity remaining from the gauge. I doubt tank shape has not been taken into account. The 700 mile figure was from some glitch or reboot and shouldn't repeat. If it does, the dealer should be consulted.

Anybody that runs out of gas in this car testing the accuracy of the fuel system should have the car confiscated from them !

[hybridbear]

I've found the DTE estimate right after filling up to be quite high. I often see over 700 miles estimated right after filling up. Only once have I managed 700 miles on a tank. I guess that's why it's called an "estimate".