Gas Tank Mystery Solved?

I'm wondering the same thing. Actually looked up how the pump nozzle shut off mechanism works. It seems it typically shuts off when the tip of the nozzle encounters gasoline. There is a small secondary tube within the nozzle, constantly drawing in air. As soon the nozzle tip is submerged, a partial vacuum sets up in that secondary tube, and this vacuum activates the nozzle release. If the you're pumping fast and/or the gas is splashing, it will shut off a little sooner. It's a bit involved, articles on the subject readily available with Google.

 

When I am in Washington.

 

Big difference between the PIP and the Liftback. With the Liftback we do not have the additional EV battery to use up to get to the gas station !

The ones that have reported running out of gas on a Liftback have reported the car coasting to a stop with no engine or battery power, or very little.

I just realized that this is in the PIP forum, so my apologies.

 

PiP or not drive. You're not suppose to drive without gas.

 

Wow, kaboom went this thread.

When I "top it off" I pull the nozzle out so the tip is just resting on the rim of the fuel inlet. I then pull the black boot back with one hand so I can manually pump the gas into the tank at a slow rate. I then pump until fuel remains visible in the filler neck. This is easily 2 gallons after the pump would "click" off on a normal auto fill. (Did that sound extremely sexual to anyone else?)

Why does it take so long to burp the tank? My guess would be tank size. Air gets trapped in the tank and can not get out as fast as the fuel fills the last bit. It's amazing what a quick shake of the rear of the car will do. Worst car ever was my 2005 Dodge Ram 3500 Diesel. It had a 38 gallon tank but due to poor design about 5 gallons of it sat above the filler neck connection. People actually sold after market kits to add a breather to the high point in the tank to let air escape!

The myth of damaging your car usually evolves around the extra components attached to the gas tank. One component is the evap system. Because of our tree huggers, cars typically have a line that allows excess vapors to travel back up and into the intake to be combusted and sent through the Catalysts. Some cars utilize a charcoal canister. Some cars (forced induction) have to use a combination of both. Typically the systems have a combination of a purge valve, charcoal tank, filter and some lines. Some people freak out these can be damaged. In pretty much all setups I've seen it's damn near impossible.

Another system people freak out about on some cars is the roll over system. Some cars have a system that detects the fuel tank is upside down through varies means and cuts the fuel pump signal.

I believe in older gen Prius the tank was actually a bladder that could rupture in extreme temperature conditions when topped off.

Other then the bladder situation the others are usually just hype from people freaking out.

 

There was a bladder, but there was no chance of ever rupturing. The effect extreme cold had was causing it to contract, leaving you with reduced tank capacity.

 

why is that? i hope it's not in the manual. i drive 15 miles per day pure ev.

 

Semantics huh? Actually you do drive with gas in your fuel tank. You just don't use it. Take that!

 

you don't know that for sure.

 

Don't go out trying to get mileage today! Stay home, warm and fuzzy but not to fuzzy!

 

you got it, just sittin' here chattin' and watching the snow fall. fuzzy will come tonight after my snowblowing duties are done.

 

No problem with a modern ICE engine. The only fuel pump is in the tank, electrically operated and pushes the fuel through the system all the way through the injectors. Diesels can be another story because they have ultra high pressure mechanical pumps driven by the engine.

Older gas engines with mechanical pumps at the engine were harder to get restarted after running out of fuel too, but would usually restart after a lot of cranking.