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Discussion Starter · #1 ·
So as some of you remember I ran my tank down to "LOW" and felt the "total range" number should have at least reported EV range in this situation - that's a discussion for another thread (an yes, I firmly believe this is a Human Interface Design 101 error to report LOW for total range when the battery is full). This thread is about what actually happens when a Gen 2 Volt runs out of gas.

Range "LOW" occurs with 0.9 gallons of gas left in the tank.
When the car actually runs out of gas it alerts you with a rather loud gong (70's Gong Show anyone) and the DIC flashes Engine Not Available Fuel Needed and then switches to Propulsion Reduced. At the same time my Volt went from Hold Mode to Normal Mode for driving.

Both these alerts are clearable. The Total Range still shows "LOW" even though I had 60 miles EV range showing under the Battery SOC meter.

Power reduced is just that - a maximum of 52 KW instantaneous power was available and the throttle responds like there's a floor carpet/mat wadded up under it. In addition, on the Mode display only Normal was available. Sport, Mountain, and Hold mode were unavailable. Mountain and Hold make sense as they both require the ICE engine. Sport Mode, which I never use, was disabled, I'm assuming, because the car had gone into a hypermiling mode of reduced acceleration. What I did notice was that acceleration during cruise control resumes were not affected.

At the gas station, first click off was at 8.8 gallons and I ended up with 9.6 gallons in the tank after I pumped to the next even dollar amount. Fuel was not visible even at 9.6 gallons based on how the gas pump was responding I suspect there was at least another half gallon of fuel pipe available - total fuel capacity is closer to 10 gallons than the tank rated 8.9 gallons. When I started the car everything came up normal - no indication the car had done any sort of fuel or ICE engine testing to ensure there was gas in the tank. Nor did I hear any main fuel pump refilling the fuel lines from the tank to the injectors.

And yes, this was the first time in my life I've ever run a car out of gas.
 

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With the Gen 2 Volt I believe you can pump in nearly 2 gallons of gas once the pump's automatic shut off is activated. In Oregon you can not pump your own gas. A few days ago I filled up on vacation at Fred Meyer in Brookings Oregon. The attendant placed the pump on slow speed by placing his pen under the handle. The pump was very slow and even though I had over half a tank of gas it still pump in over 5.3 gallons of gas before it overfilled out the tank loosing a few ounces of gas. The attendant told me this has never happened as this is how he fills up motorcycles. This did increase our range with our 2016 Volt. From that fill up we arrived home we had driven 379.4 miles and still had 166 miles of gas range remaining. The battery was completely depleted before the fillup and we never charged along the way, basically our Volt was now a hybrid. So over a 500 mile gas range with the Volt is possible.

Avg. gas mpg only was 52.5 per the entire trip dash gauge...
 

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Pumping beyond the gas nozzle's auto click shut-off can flood the gas fume recovery system's charcoal canister, an expensive repair. Pumper beware.
 

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Discussion Starter · #4 ·
With the Gen 2 Volt I believe you can pump in nearly 2 gallons of gas once the pump's automatic shut off is activated. In Oregon you can not pump your own gas. A few days ago I filled up on vacation at Fred Meyer in Brookings Oregon. The attendant placed the pump on slow speed by placing his pen under the handle. The pump was very slow and even though I had over half a tank of gas it still pump in over 5.3 gallons of gas before it overfilled out the tank loosing a few ounces of gas. The attendant told me this has never happened as this is how he fills up motorcycles. This did increase our range with our 2016 Volt. From that fill up we arrived home we had driven 379.4 miles and still had 166 miles of gas range remaining. The battery was completely depleted before the fillup and we never charged along the way, basically our Volt was now a hybrid. So over a 500 mile gas range with the Volt is possible.

Avg. gas mpg only was 52.5 per the entire trip dash gauge...
I plan on using this extra fuel space for my annual drive to New Hampshire. Most of my previous cars have had 500+ mile ranges on the highway - last year I was only going 300 miles or so between fuel ups. This is half of what my Cruze ECO was getting on the same highways and speeds.
 

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In Oregon you can not pump your own gas. A few days ago I filled up on vacation at Fred Meyer in Brookings Oregon. The attendant placed the pump on slow speed by placing his pen under the handle. The pump was very slow and even though I had over half a tank of gas it still pump in over 5.3 gallons of gas before it overfilled out the tank loosing a few ounces of gas. The attendant told me this has never happened as this is how he fills up motorcycles.
We run into this problem every time we take out Collector cars down to Oregon. We usually ask if they want to pay for a new paint job if they spill any gas on our old technology auto paint. Many/Most gas stations in Oregon have directed their employees to allow the customers with Collector cars to pump their own gas to avoid this or in one instance, I was allowed to put the nozzle into the fill hole (it's on top of the trunk area) the attendant filled the tank, then I was allowed to remove the nozzle from the fill (using paper towel to catch any drips), that way they got to "pump the gas" and I took care of the critical attach/detach procedure. This doesn't always filter down to the bottom rung or new employee and sometimes you just have to drive away or fill up in Washington before you cross the border. As one Airbnb place I stayed at put it "There are too many hippies in Oregon". You should never fill beyond first click for stated gas in emissions (charcoal cannister(s)) reason and I can only imagine it would be worse with a pressurized fuel tank. Better safe than sorry.
 

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Discussion Starter · #7 ·
Pumping beyond the gas nozzle's auto click shut-off can flood the gas fume recovery system's charcoal canister, an expensive repair. Pumper beware.
Fumes aren't the issue as they are pure gasoline. The charcoal filters are designed for this and in fact, deal with gas fumes all the time. What may damage these filters is liquid gasoline, which has detergents and other impurities. The gasoline will evaporate out as designed but the additives will remain in the filter. Each time you overfill and flood the filter with liquid a small amount of additives will be added to the filter, eventually clogging it and making it unusable.
 

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Discussion Starter · #8 ·
We run into this problem every time we take out Collector cars down to Oregon. We usually ask if they want to pay for a new paint job if they spill any gas on our old technology auto paint. Many/Most gas stations in Oregon have directed their employees to allow the customers with Collector cars to pump their own gas to avoid this or in one instance, I was allowed to put the nozzle into the fill hole (it's on top of the trunk area) the attendant filled the tank, then I was allowed to remove the nozzle from the fill (using paper towel to catch any drips), that way they got to "pump the gas" and I took care of the critical attach/detach procedure. This doesn't always filter down to the bottom rung or new employee and sometimes you just have to drive away or fill up in Washington before you cross the border. As one Airbnb place I stayed at put it "There are too many hippies in Oregon". You should never fill beyond first click for stated gas in emissions (charcoal cannister(s)) reason and I can only imagine it would be worse with a pressurized fuel tank. Better safe than sorry.
Oregon now allows self pump gas stations in rural areas. You should have seen the Chicken Little Sky is Falling reaction from some of those folks. It was actually quite humorous and made a lot of Oregonians look like real idiots. The 1992 legislative arguments against this change were just as idiotic.
 

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Sometimes the gas pumps themselves are out of whack. A few months ago a friend down in Southern California related on Facebook that he found a gas pump at his local Costco overcharging for gas. It was reading more gallons pumped than the hand held tank he was filling could hold. After getting a very lackluster response from the attendants at the Costco, he reported it to the San Diego Department of Weights and Measures. They immediately confirmed it, red tagged it, and made Costco pay a fine and re-calibrate all their pumps.
 

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Range "LOW" occurs with 0.9 gallons of gas left in the tank.
It would help if you could clarify this sentence.

My understanding is that when the volume of gas in a Gen 1 tank (and perhaps also in a Gen 2 tank) drops below ~1.3-1.5 gallons (~5 liters?), the estimated gas range switches from a number to LOW.

Of course Range LOW would occur with only 0.9 gallons of gas in the tank. You seem to be saying your display did not switch from a number to LOW until the remaining volume dropped to 0.9 gallons.

Did you use an OBD reader and an app to view the volume of gas in the tank when LOW first appeared, or was this a mathematical calculation based on an estimated range or mileage number?

Too many drivers think of LOW in terms of remaining miles, not in terms of remaining gas volume. Someone who thinks the car still has 30 gas miles of driving available might make a different decision on when to head for a gas pump than someone who knows there’s less than a gallon of gas left in the tank.
 

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Discussion Starter · #11 ·
It would help if you could clarify this sentence.

My understanding is that when the volume of gas in a Gen 1 tank (and perhaps also in a Gen 2 tank) drops below ~1.3-1.5 gallons (~5 liters?), the estimated gas range switches from a number to LOW.

Of course Range LOW would occur with only 0.9 gallons of gas in the tank. You seem to be saying your display did not switch from a number to LOW until the remaining volume dropped to 0.9 gallons.

Did you use an OBD reader and an app to view the volume of gas in the tank when LOW first appeared, or was this a mathematical calculation based on an estimated range or mileage number?

Too many drivers think of LOW in terms of remaining miles, not in terms of remaining gas volume. Someone who thinks the car still has 30 gas miles of driving available might make a different decision on when to head for a gas pump than someone who knows there’s less than a gallon of gas left in the tank.
Based on the number of gallons reported used between the time my car first went from a range number to LOW, there were 0.9 gallons left in the tank. At 40 MPG this is the equivalent of 36 miles to no gas.

The calculation was done by adding up the number of gallons displayed on the energy usage display.
 

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Fumes aren't the issue as they are pure gasoline. The charcoal filters are designed for this and in fact, deal with gas fumes all the time. What may damage these filters is liquid gasoline, which has detergents and other impurities. The gasoline will evaporate out as designed but the additives will remain in the filter. Each time you overfill and flood the filter with liquid a small amount of additives will be added to the filter, eventually clogging it and making it unusable.
That makes sense for most cars.

What doesn't make sense is that any liquid gasoline would ever get into the filter no matter how much you overfill the tank on this particular car. The tank is sealed and the filter/vent is only used when the fueling button is pressed. The rest of the time it obviously must be sealed off by a valve since preventing the filter from becoming saturated with fumes even through a year of thermal cycles with no engine use is the reason for the unusual pressurized tank design.

Just don't press the refuel button while the tank is still full! The reason not to over-fill on this car is to avoid spilling fuel.
 

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That makes sense for most cars.

What doesn't make sense is that any liquid gasoline would ever get into the filter no matter how much you overfill the tank on this particular car. The tank is sealed and the filter/vent is only used when the fueling button is pressed. The rest of the time it obviously must be sealed off by a valve since preventing the filter from becoming saturated with fumes even through a year of thermal cycles with no engine use is the reason for the unusual pressurized tank design.

Just don't press the refuel button while the tank is still full! The reason not to over-fill on this car is to avoid spilling fuel.
My understanding is that the fuel vent stays open during the entire fueling operation, then closes when the fueling hatch closes. Of course, the fueling operation is when the canister is at greatest risk of being flooded by overfueling, because that's when the fueling is happening.
 

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For most vehicles I would have no problem pumping an additional $0.25 to $0.75 worth of fuel, after the automatic pump cut off shuts off, to round up my purchase to the nearest half dollar or whole dollar (must be a mild form of OCD.) For my Volt, since I rarely use any gas, I have gotten into the habit of buying a small amount of gas every 6 months, i.e. 3 gallons. I pay in cash, in advance, and the pump will automatically shut off when the correct $ amount of fuel I have purchased has been pumped. I get a $0.05 per gallon discount ($0.15 yeah!) for paying cash, don't have to worry about credit card skimmer scams at the fuel pump. I keep my Volt's fuel tank between 2/3rd and 1/3rd full.
 

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Discussion Starter · #15 ·
My understanding is that the fuel vent stays open during the entire fueling operation, then closes when the fueling hatch closes. Of course, the fueling operation is when the canister is at greatest risk of being flooded by overfueling, because that's when the fueling is happening.
Refuelling operations are the only time the Evaporative Fuel recovery system is at risk of getting contanamated from the fuel. During normal operation this system will only receive fumes, which are contanament free. Fuel additives come in powder and liquid form. The powders won't evaporate and end up mixed with the fuel vapors so they won't end up in the canister except by overflowing during fill ups. The liquid additives will evaporate right out of the canister so they're aren't a concern.

Note - the above applies to ALL ICE engines. The reason the Volt's fuel system is pressurized is to meet CARB requirements for PZEV and TZEV vehicles - no fuel tank emissions are allowed to occur while the vehicle is not refueling. By pressurizing the system the BCM (Body Control Module) computer can more quickly detect even small leaks in this system. When you press the release button you're actually telling the BCM that a "leak" is now allowed until the next vehicle start.
 

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After the attendant filled up the tank in our 2016 Volt to the point of overflowing. We then took a nice ride for about 35 miles on gas as the battery was empty and probably burned .6 of a gallon of gas in the tank as we were getting over 50 mpg on gas.

I did notice the warning light(s) never came on or any other notice of the gas tank being over fueled. Had no issues driving home on just gas for 350 miles. I did notice that the first gas tank bar did not come off from the full mark until about 150 miles, but then we were averaging over 50 mpg on gas.

I don't think there was any harm to the fuel system. The entire incident would never had occurred if Oregon's Law prevented pumping your own gas in your car in most places. I am aware that in low population counties there are provisions where you can pump your own gas but that is up to the owner of the facility. Most places even where you can pump you own gas during the time frame mostly after 6 PM do not allow you to do so, even though it is not a violation of law....
 
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