2010 3S Reserve Fuel Capacity Question

[Oelna]

I have a weird question as a new 3 GT owner. If any of you here could make sense out of the following I would really appreciate it. I filled up my car for the first time this morning after my fuel light went on and 1 bar left on my fuel gage (just dropped to one bar within 1 mile of my fill up). The tank is supposed to hold 15.9 gallons of gas correct? I pumped in 11.4 gallons of gas (even topped it off). Does the fuel light come on with still 4.5 gallons still left in the tank? Should I assume that it is completed safe to drive all the way down to no bars on my fuel gage? It just seems like the fuel light will be on for a long time before you are in real danger of running out.

P.S. I only had 347 mile on my trip and said I had 40 miles left on my range. My fuel estimates by the computer were exactly what I got which was 30.4mpg. I do about 90-95% highway driving. I just didn't want to run low on gas in my first tank.

I have a similar question to above. When the low fuel indicator light comes on, I pump in 11.4 gallons of gas (in a 15.9 gallon tank!). Does anyone know what the exact reserve fuel level should be, and have a recommended solution to this problem?

[Dubcnea]

it depends on your mileage that you're getting. i have 1/2 tank left an i've gone almost 230 miles. it will always come on when you hit one bar. it used to be that a light would come on when you had 2 gallons left, but i do not believe that to be the case with the new setup. it comes on with one bar left, regardless of fuel in the tank. you must take your mpg into account. and the countdown on the information screen (if you have it), i believe, is a 2 gallon countdown...whereas you'll have 2 gallons left when it reads zero. but i would not be willing to test that out personally ;)

[Derrick_B]

Actually, I believe the reserve is pretty big. More like 3.5-4 gallons. I think 2 would be plenty though. I can't imagine being somewhere that took 80 miles to find a gas station.

[DailyDriver]

.

[Vater]

Yeah, I really don't see a large reserve as a 'problem'. However, when my fuel light comes on I typically have ~50 miles left according to the MID. That's never accurate (probably due to the way I drive), and I'd estimate that it's more like 30...maybe.

[El Speed3]

Ok, quick question about refueling since the subjects up in the air...

I heard a while back that in modern cars, you should never hit the reserve as it might damage something which I cant remember the name of (plus, it would be in spanish so I bet its no good anyways!). Is this true or false?

I never wait more than 1/4-1/8 to refill the tank, but I guess I want to clear that up if anyone knows the answer...

THX!

[Oelna]

Yeah, I really don't see a large reserve as a 'problem'. However, when my fuel light comes on I typically have ~50 miles left according to the MID. That's never accurate (probably due to the way I drive), and I'd estimate that it's more like 30...maybe.

Yes, 30-50 miles sounds like a reasonable amount of reserve. However I'm consistently seeing about 4.5 gallons of reserve once the light comes out. Since I'm getting ~28mpg, this is ~140 miles of reserve!

Something is obviously out of wack - I'd like to find out the specified reserve, however I can't find it documented ....

[Aetherfury]

I wait until my last block disappears and then I reset my trip thing and I drive about 20 miles. Even then I can never add more than 13.5 gallons.

[3newbie]

I immediately ran into this with my new 3GT bought in October 09. One of the reasons I chose the new Mazda was the big 60 litre tank, but I couldnt put more than 48 litres in. I took this problem to my dealer under warranty - either the tank was not 60 litres (~15 US) or the gauge was faulty. They measured and confirmed the tank was 60 litres. They called Mazda technical support who said they had no record of this problem. So get to your dealers and start complaining and we can get new firmware for the Info display. I want to decide how much reserve is OK - not some software engineer in Hiroshima or lawyer in California!

[liquoredonlife]

The fuel light is just a suggestion, and a good one. For the 2010 MS3, the light comes on when the last bar remains, which is usually right at 13 gallons even. The tank holds 15.9 gallons.

So I'd estimate 2.5 gallons of desperate times to fill up.

On some cars, the fuel pump lies within the fuel tank itself and is cooled with the surrounding fuel. Run it low too often and you shorten the life of the fuel pump.

[10CopperRed]

I have let the last bar disappear on my 10 GT and the reading on the computer was 5 miles left. Pumped 15.5 gallons in the baby.

[Kingof3rdinput]

Exact same story as 10CopperRed.

Let my bars expire, and added about 15.5, had 5-6 on my computer as well.

[gogogomoveit]

You should not let the fuel tank to run too low. Reserve tank is there as a debris/impurities collector. When you get to the bottom of the tank, there is chance that the fuel pump will pick up solid impurities into the fuel system. Also in areas of high humidity, you also risk too much moisture collecting inside your fuel lines.

[10CopperRed]

You should not let the fuel tank to run too low. Reserve tank is there as a debris/impurities collector. When you get to the bottom of the tank, there is chance that the fuel pump will pick up solid impurities into the fuel system. Also in areas of high humidity, you also risk too much moisture collecting inside your fuel lines.

Did this with my 05 SP23 for 120k not one issue 28-32 mpg per tank for the life of the ownership, sadly it was totaled a couple weeks ago....

[Lord_Zath]

I test drove a just-delivered 2010 3. Started with one bar, ended with 2 miles left on the MID. That was scary!

[3newbie]

You should not let the fuel tank to run too low. Reserve tank is there as a debris/impurities collector. When you get to the bottom of the tank, there is chance that the fuel pump will pick up solid impurities into the fuel system. Also in areas of high humidity, you also risk too much moisture collecting inside your fuel lines.

While I agree its not a good idea to use the last drop, and pick up moisture - particularly in our frozen northern climes - if the design really needs a 15 liter sump, that should be built in - not taken out of the advertised 60 liter capacity.