Are our tanks really 21 gallons?

Doesn't our, and most new vehicles, in tank fuel pump sit in a little well that only requires about a quart of gas to fill it and that's what keeps the pump cool? Also, that well is not filled up from the tank it usually should use returning gas to fill.

If that's the case, how can running a vehicle down to having 2-3 gallons of gas in the tank hurt the pump? I can't disagree that constantly putting 20-21 gallons would hurt ...

Also, http://www.yachtsurvey.com/myth_of_condensation_in_fuel_tanks.htm
(Maximum amount of water condensation in a 200 gallon tank is 1 oz. Or, in our truck tanks .. 1/10th of an ounce.)

If any of what you said was true vehicle manufacturers wouldn't let people run the tanks dry. You would run out of gas with a small reserve left to cool the pump.

This conversation is the same most of the MPG threads ... full of guesses and what people have heard, not facts.

 

The most I've put in is 20.7, also have put in 20.5 once. I normally fill up with 19-20 gal. I've heard the pump cooling thing on _several_ car/truck boards before. Only documentable cases of premature pump failures I've ever found was on some 90's model Chebbys. Don't believe it enough myself to fill up before 19-20 gallons.

Also, only way to pick up more condensation/sediment from the bottom of the tank is if the fuel pickup actually floats on the top of the gas, don't really think that's the case.

Now, condensation formation on the inside of a partly empty tank, definitely some logic in that....

 

Except that my dual wall coffee cup can have 190 degree coffee in it and I can set it in the snow and not have an drop of condensation form on the outside of it. Or, I can put ice water in it and set it outside in our blazing 80 degree weather (Seattle ) ... ditto.

Technology is a beautiful thing. I wish these car manufacturers would figure out a way to build a tank that didn't let floods of condensation in ... oh wait.

 

It's not going to cause the pump to crap out on you the next day or anything, but it will shorten the service life of the pump. Would you rather have 1 qt cooling the pump or have the pump submerged in 15 gallons. Obviously the smaller volume will heat up much quicker. I have had friends run their cars out of gas and as a result, needed to replace the pump. Not the typical case, but it happens and makes for an expensive fix for a dumb mistake. Believe whatever you want to believe, it's your truck, but nothing positive comes out of running a gas tank that low.

The condensation thing has happened to me with motorcycles a few times because they sit more than a vehicle and the smaller engines are less tolerant to water. It sucked, I had to drain the tank, purge the lines and empty the carb bowls and start fresh again. In the winter time is a real problem because of the freezing. If water makes it's way through the fuel delivery system and freezes along the way it can stall out the car and there's no quick fix other than tow it to a heated garage and wait.

 

Tank = 21 gallons. In the 08 reg cab after filling to brim. Yes, I put 2 more gallons in after the pump clicks the first time. No, nothing is ever spilling on the ground. After it clicks then I run the pump as slow as it'll go and move nozzle end as close to the small opening of the tamk as possible. This is only for advanced ehtyl pumpers, lol. Anyway, I hit 145 miles at 3/4 mark all the time with AC going and doing 67mph. I have gotten as much as 165 to 3/4. I then only get to 250-265 miles to 1/2 tank. I usually have 330-360 miles at 1/4 and the light starts coming on anywhere from 375 to 425. This is 2/3 hwy 1/3 city mix. Then fillups are in the 18-19 gallon range. I usually get 22-24 mpg. The emptier the gauge reads, the less miles per quarter tank on the gauge is what is happening. My light comes on just shy of 1/8th it seems so yeah, 3-4 gallons left when light comes on. WTF was the point again?.......Oh yeah, definitely 21 gallon tank.

 

being poor

 

I personally keep it below 1/4 tank. KEEPING IT FULL IS WHAT CAUSES THE TACO LEAN that everyone whines about. So instead of putting an expensive trim plate on my drivers side coil assembly I just run it lower than 1/4 tank. Haha!!

 

x2 I usually fill up by 1/4 left.

 

1 qt or 15 gallons, it doesn't matter. The fuel in the well holding the pump is constantly refreshed by unused fuel returning to the tank. It's not going to stay any cooler in a full tank because the well only holds 1 qt, regardless of whether there is 1 gallon in the tank or 15.

 

You consider $20 to be expensive?

 

I disagree on the basic principles of heat transfer but hey, your truck you can do whatever your little heart desires

 

and a $70 alignment

 

I get it, I'm just thinking about this like the water temp in our trucks. Everything has a safe operating temperature range. What I'm reading on a fuel pump is way higher then you could ever get with 2ish gallons in the tank. Obviously the gas going up to the engine, and then back down, could be a bit hotter with only 2 gallons than 15. But it's nowhere near a warning temp for the fuel pump.

I'm a temperature whore. Been building PC's and overclocking them for years so safe working temperatures is important to know and understand.

 

I run mine dry because I don't like having to stop for gas every other day. I fill up every 4-5 days by running it 20-30 miles with the light on.

I think that sediment story is horse shit. I dropped my tank in my last vehicle at 150k miles to put a bigger walbro fuel pump in (turbo'ed the car) and my fuel tank was clean as a whistle. Not a spec of sediment in the tank after 150k miles. The sock on the pump was also still clean.

I also don't believe the fuel pump overheating...the only time I've heard of issues was with late 90's chevys. I put over 200k miles on my honda accord, and 150k on the accord before that and never had a fuel pump failure. 95k on my truck now running it dry twice a week. No fuel pump failures here.

 

Call it what you want but I'm a busy guy and have a schedule to maintain. Having to stop for gas every other day costs me time and money.

 

I get it and I'm not saying running your truck dry would cause the pump to just quit but routinely having a pump operate at a higher temperature (although still within the safe operating limits) will still cause premature failure vs one that was kept cooler over a long period of time. The life span of the pump is pretty long so it may only shave a month off, it may shave a year off so I suppose you could argue that it's negligible in some cases. Still wouldn't do it to my truck

 

Depends how much the dollar is worth next week. I just think its funny. Really pretty simple....gas light goes on, truck needs gas I get gas, gas light goes off.

Now I may be more concerned with fuel capacity and mileage when the truck is old and beat down and the fuel gauge breaks and I'm too lazy to fix it. That's when my odometer and tank capacity will be more relevant to my fuel management plans.

 

You realize you have an extremely RARE Tacoma then?

Have you actually run out of gas then filled it up? It is 18 gallons form the E Line to full... but your tank still has 3 more gallons below the E Line on your gauge.

I had an '05 as well... same as my '10... 80 liter tank (21.1 gallons)... and yes if it is cool, and you topped it up the neck, I wouldn't be surprised if you got a gallon or more in there above the true tank.