[Intrepid175]

Agree with Hyperlight. The fuel pump is cooled by the fuel. Running it down until the pump is no longer submerged isn't good for it. I would think that going that far down every once in a while might not be an issue but you really don't want to make a habit of it. I've gotten mine down to 1/8th of a tank a couple of times and took a touch over 12 gallons when the pump clicked off. I haven't had it low enough to see a low fuel light yet. For those of you who have seen the low fuel light, what was your gas gauge reading when it came on?

Thanks and Drive Safe,
Steve R.

 

[Intrepid175]

I don't think a fuel gauge that say E, while the tank still has 2.5 gallons left in it, is accurate. I would expect that E stands for Empty.
Running out of fuel, as in only fumes left in the tank, will not destroy your electric fuel pump. If you ran out of fuel on a regular basis, then yes, you COULD damage the fuel pump over time. The apocalypse will not come if they ever run their tanks down below 1/4. Is it a good idea? No.
I ran mine down twice to Empty. The world didn't end, and my fuel pump never broke.

Nobody said the car would grenade itself if you run down to "E." They just said what you basically said. It's not a good idea on a regular basis.

As for the "accuracy" of the fuel gauge? I've driven my fair share of vehicles and worked for car dealerships for over 10 years and by my experience, there's no such thing as an "accurate" fuel gauge. The fuel gauge is there to give the driver a "general" idea of how much fuel they've got left and that's all. As we drive our cars and gain experience with them, we'll get an idea of how much is left in the tank at any given point. Then we can figure out how much farther we can drive but if a person is expecting to put 8 gallons of gas in their 16 gallon tank when the needle touches the half way point, they're probably going to be disappointed.

Drive Safe,
Steve R.

 

[Intrepid175]

Just a couple of extra thoughts:
Fuel vapor pressure keeps water condensation out of the tank, so in really cold weather (a.k.a. this entire winter) it's best to keep the tank at least half full.

A near-empty tank may allow air in the fuel line when it's sloshing around during turns, etc. That's usually not a good thing either.

---
I had a 1983 Ford Escort gauge that showed full seemingly forever. Once it dropped to 3/4, the tank was basically empty. My buddy's Escort did the same thing.

Point taken on the condensation thing. Generally speaking though, if you're driving on a daily basis, condensation isn't going to be that big a deal. If the car is going to be parked for an extended period of time in a climate where condensation is likely, then your suggestion to keep the tank at least half full certainly has merit.

On getting air in the fuel lines? If the tank is low enough for that to happen, even during turns, the car is probably not going to be running much longer anyway. The fuel injections systems on our cars run under some pretty high pressures and they don't respond well to air in the system. At the very least, the engine's not going to be very happy!

That's interesting about the Fords. I worked for a Lincoln dealer back in the early 80's. We had a Mercury Capri (rebadged Mustang) come in that also stayed on full, "forever," and then dropped dead from fuel starvation at a quarter tank. The owner "thought" they were getting really great fuel economy. They got a new sending unit under warranty.

Drive Safe,
Steve R.

 

[Intrepid175]

Some cars have the fuel pump in a canister that keeps the fuel pump submerged in fuel until the last quart or two of fuel remains in the canister. The tank can be empty before the the pump drains the canister.

Really? Didn't know that one. Not a bad idea!

 

[Intrepid175]

There's articles on this "phenomenon". Every vehicle manufacturer sets E and F incorrectly on purpose. Vehicle gauges are designed to not start sliding off F as soon as you pull away from the pump, and are set to not sputter out as soon as the E line is hit. For the most part, it's to make the consumer feel better about their vehicle fuel consumption.

I have to admit, I do feel better when I get close to 60 or 70 miles before it puckers off of full than I do when the needle starts moving after 30 miles. Having said that, I do think car manufacturers underestimate their customer base as a whole. Sure, there are folks that come up with some really off the wall expectations but they're not the norm by my experience. I think most of us would find it quite refreshing if they filled the tank and the needle fell in a linear manner until it hit empty and the engine quit from lack of fuel. It wouldn't take us long to get used to the idea that it really "means" empty when it "says" empty! As it is, we're just guessing when the low fuel light comes on and the needle reaches "E." I don't like that at all.

Drive Safe,
Steve R.

 

[Intrepid175]

How often do you get out to the east coast?

:lol: Ok, you got me on that one. I've worked for car dealerships and trust me, I've seen my fair share of......well.....I'll be nice! Honestly though, those folks are not the majority. They may be the one's we always remember, but they're not the majority.

Drive Safe,
Steve R.

 

[Intrepid175]

I've been driving since the early 70's. I worked in car dealers for nine years and in all that and all the cars I've owned, I've never seen one with a 100% accurate fuel gauge. Customers would complain but there wasn't a darn thing we could do about it. It simply is what it is. The only time we swapped a sending unit under warranty, it was an 1980 Mercury Capri that would stay on full literally "forever" and then fall dead with an empty tank at the 1/4 mark. "That" they fixed!


With the advent of all the electronics, you'd think it would get better but obviously not. I've driven as far as 30 miles with the DTE reading 0 miles to empty. The low fuel light was on noticeably longer than that. The Rav took 14.8 gallons to fill up. As long as the car is consistent about how the fuel gauge reads, I really don't care. One of these days, they'll make one that's accurate and driver will wind up sitting on the side of the road, out of fuel, complaining about that.

 

[Intrepid175]

I don't make a habit of pushing the car as far as I indicated in my last post but I'm anal about manually keeping track of my fuel economy and the numbers said it shouldn't be a problem. Of course, I was taking a chance. A lot of vehicles won't let you access the last gallon or so, so I could have easily found myself walking. Normally I try to fill her up no later than somewhere between the 1/4 mark and the point the low fuel light comes on but every once in a while the circumstances require pushing it a bit.


Drive Safe,
Steve R.

 

[Intrepid175]

As a new owner of a 2015 RAV4 LTD, I am concerned that when the low fuel light came on, the tank took only 47 liters (capacity 60 liters). Is this to be expected?

Hi Caram,

It's perfectly normal these days. The needles near empty, the low fuel light just comes on and the tank is still a quarter full. Mine does the same thing and so have the last few cars I've owned. On one occasion, I pushed almost 30 miles after the DTE display was reading 0. I'm going to try "really" hard to never do that again, I was sweating it at the time. I know many want the fuel gauge to be 100% accurate but that simply doesn't happen these day. The fuel pump is in the gas tank and the fuel actually acts as a coolant for the pump. Many have speculated that the bias in the gas gauge is there to help protect the fuel pump. That makes as much sense to me as any other explanation I've heard. Bottom line is, IMO, as long as the gauge is consistent about it, you'll get used to it. The low fuel light comes on and you're at 1/4 tank. Works for me!

Drive Safe,
Steve R.

 

[Intrepid175]

Frankly who cares? If you let your tank get that low then you are on your own. When it gets to 1/4 then fill it up and continue on. I've driven for 50 years and have yet to run out of fuel. None of my previous 40 cars had a "warning light" to tell me when I was low on fuel. I simply looked at the fuel gauge and pulled over to get gas. Is that a difficult decision? I just don't see the point of this post.

Apparently, a lot of folks care, the question keeps coming up. Why? I have no idea! I used to work for car dealers back in the 70's and early 80's and we occasionally had customers coming in complaining about inaccurate gas gauges. These customers have always been there, and always will be. The only one I remember that we were able to do anything about was a Mercury Capri that would run "forever" on full, then fall dead on the side of the road, out of fuel, with the gauge still showing 3/8th of a tank. That one was a new sending unit but beyond that, it is what it is. As I said before, as long as the system is consistent, I'm fine with it.

Drive Safe,
Steve R.