Running on Empty.......

It's possible that the Toyota engineers considered the running out of gas scenario and shut off the electric fuel pump either when there isn't any fuel to pump or the temperature exceeds a certain limit. The manual doesn't mention it being a problem:

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Running out of fuel​

When the vehicle has run out of fuel and the hybrid system cannot be
started, refuel the vehicle with at least enough gasoline to make the low fuel
level warning light (​

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→P. 433) stop flashing. If there is only a small amount of
fuel, the hybrid system may not be able to start. (The minimum amount of
fuel to add to make the low fuel level warning light stop flashing is about 1.3
gal. [5.0 L, 1.1 Imp. gal.] when the vehicle is on a level surface. This value​

may vary when the vehicle is on a slope.)

It seems like there would be large warnings to not run out of gas since it woud be a big warranty problem if running out of gas could cause the fuel pump to fail, since I don't think running out of gas would void the warranty.

The Toyota engineers seem to be pretty clever, which is why we love this car so much ;-)

My $.02

 

I could go with that. Maybe some of the posters on this thread are over-exaggerating the dangers of running out of gas with these machines.

 

ever since i got my first prius in 04 i have always been warned to NEVER let it run out of gas. i had an 07 and an 010. the same message was delivered over and over again. it seems that is about the only way you can damage the main battery pack. for me im listening. for those who live on the edge... well, you live on the edge.
that is why i dont even go to 2 blips. even on my big trip to daytona i did not even let it get below 3 blips. just too paranoid i guess.

 

The fuel pump will run dry for about 10 seconds, the length of time that the car tries to crank the engine. Then the car codes and the pump will shut off.

Every time you run out of gas, you increase the risk that the pump will be permanently damaged. Once in a blue moon probably will not cause a failure. Toyota pumps are quite a bit more robust than, say, Chrysler, Ford, or GM. But go ahead, run out of gas on every tank, so you can prove us wrong.

 

That sounds about the same as what ENgineer said, except more technical
and detailed, so I can go with that as well. Who is "you", and who is "us"?

 

You, who seemed to think that the recommendation provided by us was overly cautious. I'm actually more on your side, where I agree that the system is fairly robust and running out of gas a few times over the car's life is not likely to hurt anything. But in the end, there's just no reason to subject the car to this unnecessary treatment.

 

OK but it is tough to be on my side because I don't actually have a side and cannot even choose a side until I hear from people such as yourself, who are much more expert. A few of the posters keep talking about how "stupid" it is to run out of gas, which is not as informative as accurately indicating exactly how "stupid" it is (and more details on why it is "stupid").

The only question I would have left at this point would be "how much would it typically cost to replace the fuel pump (part and labor) in the Prius C?

 

About $500?
What does it usually cost to replace a fuel pump on a car?

But in my opinion, damage to fuel pump is not nearly as worrisome as damage to the HV Battery, and time lost carrying gas back and forth.

 

Providing 4 real-life examples wasn't enough?
No fuel = no cooling of the fuel pump = shortened pump life

How is that not detailed and specific?

(And, by the way, my previous career was purely Electrical Engineering, now I do primarily Development with some EE mixed in. This is, by definition, an expert opinion. )

 

Im not sure why anyone would let their car run out of gas. Especially a Hybrid that allows you to get much farther on a single tank.

Next thing I expect to see is someone asking how far you can go between oil changes before the car seizes up.

"So how much would it cost to replace the car?"

 

Wow...this is a subject that gets people all excited....look at this whopper 46 page thread in the Gen III forum...

http://priuschat.com/forums/gen-iii-2010-prius-main-forum/64211-warning-running-out-gas-gen-iii.html

I look at it two ways....

1.) I think everyone knows that it is bad to run out of gas in a prius or any fuel injected car for that matter....more so apparently in a Prius....nobody wants to...(Except for Bob, who has done detailed analysis and documentation of what happens in a Gen III in the above thread...much to be learned from that long thread if you can get through it!)

2.) If for some crazy reason or circumstance you do run out of gas in your Prius, it is good to know what happens to the car and what the consequences are.

-M

 

Look, back in the day when cars weren't too complicated and even I could do mechanical work on them, the biggest problem with running out of gas was lining up a couple of bucks in order to get more gas. Even then nobody was real keen on running out of gas. So nowadays, as complicated as cars have become (as they become increasingly computerized) I doubt it is really necessary for electrical engineer/developers to write posts about how stupid people are if they run out of gas.

Like managerman has said, the unthinkable (for some of you guys it seems to be unthinkable, anyhow) may happen, and a person could conceivably run out of gas (the horror!). It's nice to have some idea of what the ramifications of this are, beyond "bad" and "stupid".

 

There are degrees of stupid. Most of us have run out of gas at one time or another. That qualifies as mildly stupid.

Then there are people that try to drive a Prius to the gas station on battery alone once they run out of gas, stopping only when the car shuts down. That qualifies as pretty damn stupid.

Then there are people who repeatedly restart their out of gas Prius to try and drive to the gas station on battery alone. That qualifies as "take my car away from me before I hurt myself or someone else" stupid.

As to what to expect, that's been explained dozens of times on these threads. What more do people need? Do we have to print it on a large orange stickers and paste it to their windshields?

As the old saying goes, you can't fix stupid.

Tom

 

This posts takes the discussion in a couple different directions. One direction involves evaluating the stupidity of what the OP did. That's not so interesting to me, but perhaps more interesting to assorted bitter, tired and angry old-timers inhabiting the general Prius forums.

I am more interested in the bitter, tired and angry old-timers themselves. I would just as soon avoid them, because I am really want to discuss the Prius C, and not every Prius that was ever made. I have little or no ability to read something written about a different kind of Prius and then be able to determine with certainty whether what I read about the different model Prius would apply to my Prius C.

Yet I run across posts frequently in the Prius C forum where general Prius users are expecting just that -- that Prius C users get their information from posts that pertain to the other models. Is this the only internet forum covering Prius C's? Is there a forum where Prius C users can discuss stuff without bitter old timers leaping in and telling them how stupid they are?

 

Fair enough, that's a good point.

 

I thought of this post as I read this. Engineering Infrastructures For Humans | Standalone Sysadmin
We really should plan on our users ignoring our advice.

 

Good article. The author makes a very good point, and does it simply and convincingly. As engineers, we know that humans are just that: human. We all make mistakes, and we often think we know better than the person who designed something.

When we engineer a system, we have to take this into account, and not only anticipate failure, but try to direct behavior. Since this is a "running on empty" thread, the fuel system in the Prius is a good example:

The Prius has an easy to read fuel gauge. A "low fuel" icon lights when fuel levels get low. The icon flashes and a chime sounds when fuel levels are critical. A "Get Fuel" message pops up on the MFD. In short, the Prius does everything but slap the driver when he needs to add fuel.

Unfortunately this doesn't always work. Drivers have learned that engineers build reserve into the system, and some drivers try to beat the system by routinely using this reserve. Some will get caught, at which point we hope the engineers have gracefully handled an out-of-fuel situation.

Tom

 

The C powertrain is substantially equal to a Gen II. The battery pack is a little smaller, because the car is a little smaller. Seems like, you asked how the fuel pump worked in the C in the case of being out of gas, and got authoritative, correct answers, because running out of gas follows the same failure mode algorithm for all Prii since 2004.

So if you say, "In my C, I observe...", don't be surprised if an old timer will chime in and say, "This is a common feature of all Prii, and here is what you need to do..."

Someone else in another thread asked about towing with a C, since it has a zero tow rating. Well, zero towing capacity per Toyota is a common feature of all Prii, yet people do in fact tow with them just fine after deciding that the rewards outweigh the risks, and there are some issues to be aware of. Most C owners would not be able to address that question, because the car is so new, and being little, it is not normally a car that people would buy thinking that they would be towing anything with it.

 

In Germany it is illegal to run out of gas.