I can confirm that what your manual tells you in a couple of places is accurate. If your engine is not available because you ran out of fuel (or if a malfunction prevents the engine from starting), the vehicle can continue to be driven in Electric Mode until the battery is depleted, but it will have reduced acceleration. If you restart the car, it will probably post a message on the DIC: ENGINE NOT AVAILABLE ADD FUEL. And then it will run on battery with reduced performance.

I can also confirm that when you run out of gas in a Gen 1 Volt (in my opinion, the best way to end an FMM if you want the longest interval possible until the next FMM), the computer shuts off the engine before the fuel is completely out of the lines (and then you can drive on any battery power, but with reduced propulsion). I suspect it does this for the Gen 2 Volt, too. This small amount of "old gas" left in the lines actually has an impact on the timing of the next FMM (instead of a full 365 days, it may be a few days to a couple of weeks shorter than that, depending on how much "new" gas you add, i.e., fill the tank, or just add the ~1.5 gallon minimum).

 

Hmm, maybe I'm mistaken that the car ran down to fumes. The thump of the engine shutting off is not something I experience when it shuts off under normal operation conditions (which happens often, obviously), so I just assumed it was a hard shutoff due to fuel exhaustion. I suppose under normal conditions I'm not experiencing engine shutoff while driving at highway speeds, maybe that explains the difference.

Interesting also that at least in Gen1, restarting the car, without adding fuel, won't let it operate normally in battery-only mode. From an engineering perspective, I guess the logic is that the range is too short for it to operate in battery-only mode without at least a little gasoline backup on board, so it limps along in reduced propulsion mode to maximize battery range until you add at least a little fuel.

 

I suspect that the reduced propulsion mode is to encourage you to add some fuel sooner, rather than later. When the car runs low on battery power, it is programmed to switch the engine on, but when the engine isn't available and the battery runs low, bad things might start to happen when you're using the last bits of battery power which the car is programmed to avoid by switching to gas

Don

 

The goal is not to run out and get stuck. There's a limit to how much the car can protect you from yourself.

 

Well that's what's interesting--the engineers decided that rather than let people choose how to use whatever battery capacity they had when the car ran out of gasoline, they would protect them from themselves by forcing the car into reduced propulsion power mode to extend the range, even if the battery was full. So sure, there's a limit, but they decided to go all the way to the limit.

 

I've done this twice in my 2017 Volt. Once on purpose and once because I misjudged how far to the gas station during FMM. The car goes into reduced propulsion mode (~50% power) to conserve battery by preventing high power acceleration, but other than that it keeps right on driving.

 

Sorry to be acronym challenged, but could someone tell me what FMM stands for?

Tom

 

I guess another way to think about the fact that the Volt doesn't want to be operated with zero gasoline on board--no matter how much battery charge there is--is that there are rare conditions when it will choose to operate the engine even though it has plenty of battery left, and obviously that's only feasible with some gasoline in the tank.

And this is obviously in addition to the fact that the battery on this vehicle is relatively small, which is the main reason why it's designed to always have some gasoline-powered reserve capacity.

I suppose another way of putting this is that this isn't a battery or gasoline vehicle, this is a battery and gasoline vehicle.

And yes, much of this is pretty obvious, and yes, it overlaps with things others have said above.

 

I'm just bemused by the number of people unhappy that the car makes it difficult to strand themselves. grin

 

If you like this feature so much, it could be upgraded so that your car is always in reduced propulsion mode, making it even harder for you to strand yourself. Oh wait, that's called a Prius

 

except when there is no fuel there is no pressure, so no load on the pump to produce heat, it just freewheels

 

I've wondered about that, but the conventional wisdom is that the pump can get damaged, right? In addition to little load on the pump as the fuel runs very low, presumably shortly after the tank runs dry the pump also stops running entirely because the engine stops, right?

 

FUEL PUMP PROBLEM-8 MOST COMMON CAUSES - (despairrepair.com)

 

when the fuel is low it sloths around in the tank you start pulling air into the pump and it starts to cavitate the impeller
, thats hard on the pump. the other thing thats hard on the pump is a semi plugged filter, now you have a pressure drop across the filter that makes the pump run at a higher pressure pulling more current across the electrical connector, causing it to fail. impeller damage from crap in the tank has pretty much stopped since they have put a sock in front of the pump unless the sock fails
i have seen the failed sock get pulled into the pump and locked it up

 

During a road trip, I decided to see what would happen if I drove my Gen2 (2017) Volt in hold mode until the gasoline ran out (while having plenty of battery power--i.e. 4 out of 10 bars--available). My expectation was that the car would detect extremely low gasoline levels and automatically switch to fully electric propulsion. That's not precisely what happened.

When the gasoline engine shut off, it made a bit of a thump, my best assessment is that it literally ran down to fumes. I don't think I damaged anything doing this once, but it's not something I would intentionally do again.

The car seamlessly switched to full electrical power, but I got a reduced propulsion power warning and the car would only limp along at about 60 mph, despite there being plenty of battery power. My guess is that the engineers' logic is that if gas was fully depleted, electrical power should be rationed to maximize the range available to be able to get to a gas station.

At the same time, I'm guessing that if you fully depleted the gas, and shut off the vehicle, and turned it back on, it would then run normally in electric-only normal mode as long as you had sufficient battery power. Can anyone confirm?

When I stopped at a gas station to refuel, everything was back to normal operation again.

 

wow, with software on the volt a bit of a crap shoot, it took some balls to try anything operationally different with a Volt. Glad to see the windows didn't all go down and stay there for 24 hours. BTW, I lov my Volt and will pound on it till the warranty runs out before buying whatever the EV standards is in a couple years. With the diversity of driver needs in the US, I expect the Volt design to inspire other EV/Generator designs, it just makes too much sense...

 

Unfortunately the brass at GM weren't paying attention when consumers say they love it and they also didn't pay attention when the price of used ones are on the rise. They just know that it wasn't profitable enough. It takes time to recoup all of that R&D when you actually make a really good product. Toyota and Honda didn't earn their reputation and market share by abandoning a good idea because it wasn't profitable enough. They kept at it and making it better and better with each generation. In the 60's and 70's, Japanese cars were considered junk and laughable. In the 80's and 90's Korean cars were considered the same. Now look at them.
GM tried to abandon the Corvette so many times and the engineers had to work in secret during the production of the C7. Now we have the C8 mid-engine Corvette and a possible Electric Corvette if they don't pull the plug again.

 

The Volt is a great car and a marvelous feat of engineering. But it is simply too complex, too expensive to make, and too expensive to maintain. The writing was already on the wall when they pulled the plug. With EV charging infrastructure on the rise, there is simply no point in making a market loss leader. Tesla initially lost money on every car but demand turned that equation around. The Volt has never shown any substantial demand. I find that unfortunate myself, but I can't deny reality either.

 

When Toyota production line first ran in America, it stopped over 100 times a day. The US plant manager expecting to be fired was congratulated by the CEO for caring so much about quality that he orchestrated the stoppage. As you may be aware that production line stoppage could potentially cost $10K to $20K a minute!
Having worked at General Motors as a line leader for over 10 years, I could not say the same could be true for our fate.

 

When Toyota production line first ran in America, it stopped over 100 times a day. The US plant manager expecting to be fired was congratulated by the CEO for caring so much about quality that he orchestrated the stoppage.

Those early US built Toyotas (the Kentucky plant, I assume?) were still not as good as the Japan built ones. I've owned 3 Camrys from Japan and one from Kentucky built in those early years.

The Volt is my first American vehicle since my '67 Ford Truck in high school...

-Charlie