Fuel Additive and running out of gas

In a Prius there’s running out of gas, and then there’s running out of gas and letting the computer keep trying to restart the engine until the battery is dead too.

Just running out isn’t so bad, but some models require that you add at least 3 gallons before they register that they have received any new fuel- I think that’s one of them.

Running out and allowing the computer to kill the battery is bad news, usually means tow to a dealer, then them borrowing a grid charger from the regional support center. Big mess.

I don’t bother with additives unless it’s old/primitive enough to have a carburetor.

 

We often refer to it as Pray and Pour... Once or twice a year I like to use it on long drives when I'm going to run a whole tank of gas through the car in a day behind the wheel. Techron or similar product is what I use... Essentially what these additives do isn't much difference than the additives they mix into the highest priced gasoline, but maybe a little more potent.

 

I don't know exactly how to quantify how bad running out of gas is, it happens, mostly by accident or forced unfortunate situations.
Given that the Prius is a Hybrid, my advice would be, just strive to NOT run out of gas. I think clearly not running out of gas is better than ever running out of gas.

Read threads here, and in other automotive forums that talk about today's modern fuel pumps being submerged within the gas tank. Some people swear running out of gasoline puts the fuel pump at risk. I don't know how real this risk is..as I simply do NOT run out of gas.

As far as fuel additives go? I wouldn't use the adjective "needed".
I kind of feel like if your vehicle NEEDS a fuel additive to run decently, then it probably has problems that go beyond just needing a fuel additive.

That being said, superstitious ritual has me running a fuel additive (Techron) 2-3 times a year.
I like the pictures of the impotent, tar clogged fuel injector, next to the gleaming Excalibur like fuel injector, with the implied promise that with use of the product my fuel injector will look more like the clean one.

My vehicles now, are newer. Does the use of a fuel additive help? Really, I'm going to say overall I'm doubtful it is really making a big difference. But for occasional usage? The cost is low. I do it for ritual and just in case there is benefit.

Also, there are fuel "additives" in Top Tier stations fuels, that will exist without you adding anything. So if you are filling up at a top tier station, it's not like you aren't already using an additive.

 

I haven’t studied it carefully but I don’t think it would be reasonably possible without first converting the fuel tank to a traditional bagless type. I know someone was working on that- looked like a very involved project.

I don’t mean to be obtuse, but the “why” isn’t obvious to me. How would a different fuel gauge help with additives? Or have you moved on to another problem?

 

Imagine if you put a gauge like that inside a water balloon that would expand and contract in overall size based on how full it is and that's precisely what the problem is when you have a Prius rubber bladder inside your gas tank. The design concept was that with the rubber bladder you don't have polluted air displaced from the tank when you fill it up. Most cars use a charcoal type filter on this polluted air. The bladder idea was too problematic in multiple ways though so they stopped doing it in Gen3 Prius... Also Gen2 Prius in places like the UK never had the bladder system.

If you want a truly accurate measure of fuel used you need to figure out how to add a fuel meter onto the fuel line that's capable of working with the types of suction / fuel pressure that normally occur in that system.

 

I don’t know how much it was to get your TDI restarted but if you run out of gas in your Prius and accidentally run the battery down to nothing and damage it, it’s gonna cost more than 1,600 dollars for a new battery. If you do it yourself.

 

No

 

Gen2 has the problem if you run out of gas, if you also then run too long on the batteries you will discharge the HV Batt totally, and that is not good and could kill on older battery. Gen3 fixes this by not allowing the motorist to completely drain the HV Battery upon fuel exhaustion. So if you do run out of gas, you do not want to coast too far on the battery. Then I think you have to add 3 to 4 gallons before the gauge comes off EMPTY, I forget never did that.

If you go to TopTierGas.com stations, you should not need additives.

 

Draining a battery down really low doesn't damage it. And in fact, improving a battery pack's health via re-conditioning requires discharging the battery to increasingly lower levels. The real challenge with draining a pack down below what the car need to function is you have to get a High Voltage trickle charger, which can be expensive if you or your mechanic is not equipped to do the work...

 

Yes but you charge the battery first to balance the cells then discharge at a lower rate then driving the car. There are known incidences here of traction batteries being damaged by running out of gas and driving on the battery.

 

Your question implies you don't like the current gauge? It's not bad, has what, 10 indicator bars? I've never had a problem with it. Most often I fill when it's got below half, 2~3 bars at the lowest.

 

Well, yes a super heavy discharge can cause damage in an older battery, but that's the exception not the rule because once the pack voltage is too low to start the engine or run the electric motor, there's usually still quite a bit of voltage remaining and you simply just charge it back up and you're good to go, unless your battery pack was allready at the end of it's lifespan and the first module is about to fail.

 

Well the guy has a 2005 Prius with 192,000 miles so I wouldn’t say the battery was factory new. If it’s the original battery I say why push your luck.