Out of fuel with 2 gallons in the tank
 

I don't normally let my BRZ get down much below 1/4 tank but recently I was on the Interstate and not paying attention to the gauge when "beep" the fuel low indication came on. Withing one minute the car began to buck and loose power. A mile later I was on the side of the road calling AAA. They brought me the standard 2 gallons of 87 octane crap and off I went driving gently the 4 to 5 miles to the closest gas station. I filled the car - it took 9 gallons. I expected it to take about 11+ being a 13.x gallon tank. Since I have a 93 tune and turbo I really wanted as much premium fuel to mix into that 87 octane stuff as possible so I attempted to top it off. By 9.5 gallons the fuel was about to spill out the filler. OK so my math is that ZERO plus 2 plus 9.5 = 11.5. Also isn't the reserve supposed to be about 2 gallons? Anyone have any ideas on why I apparently could not access and use the reserve? My mechanic rattled off something about an issue with the scavenge system in the fuel tank. Only other thing to mention is that my Port Injection fuel pump was replaced with a bigger unit when I went from 7 to just over 9PSI boost. Not sure that would be involved but it's in that area. Help!

My general experience has been that tanks will almost never hold as much as they're rated for. I believe the rating for 13 gallons is a theoretical full tank, with no air space or anything. However, reality requires expansion room, etc. so the tank will hold less when filling it at a pump. Motorcycle tanks are notorious for this as well.

The apparent lack of reserve after the low fuel light would be more concerning for me though. I'd think there would be something that could be adjusted on the pump/sending unit assembly to give more warning, but you'd have a hard time convincing a dealer to go to all that work and cover it under warranty...

Well, at least you now know where the NEW "E" is on your car .....;)


humfrz

I've driven mine down to the point where it took 12.5 gallons. If your in tank pump was replaced are you sure it is properly configured to draw fuel in when the tank is at 2 gallons or less? It might be something to check out.

Most I've ever put in my tank at one time has been ~11.4 gallons, but I've never run out of fuel so I don't know how much I had left. Needle was at or slightly below 'E'.

Chalk it up to a life lesson and be more careful? I'm not sure what you really need help with.

Perhaps a clear understanding of how the fuel tank, pickup and scavenging work would be helpful. I agree with VenturaII that I'll "have a hard time convincing a dealer to go to all that work and cover it under warranty." and figure being armed with more facts would be good. Another might be what others have seen on this car for distance on reserve. I think one mile is clearly an issue but if I know that normal is at least 40 miles that would be good to be able to say confidently.

It is not normal for the car to die that soon after the light turns on.

my fuel light always come on after around 2 gallon as well. thought its normal...

that's really odd, when my fuel light comes on, it takes between 9.8 and 10.5 gallons to fill up and it comes on with about 1/8 of a tank left on the needle. i normally burn another gallon or so before actually getting to the gas station and on average take about 11 to 11.5 gallons to fill up.

It is a ~13 gallon tank with ~12.5 usable gallons of fuel. The bottom 1/2 gallon is not accessible. It's designed that way to allow for sediment and condensation to settle in the bottom of the tank and not be picked up. You put 13 gallons into a dry tank, you can only get 12.5 back out through the motor.

The warning light usually comes on when there is 2 to 2.5 gallons of usable fuel left. There is apparently some variation. If you fill it up right when the light comes on, you should pump about 10 to 10.5 gallons. The most you should ever be able to pump is 12.5 gallons, but that will mean you ran it out of gas or came dangerously close to doing so.

Perhaps the "two gallons" from AAA was actually three gallons. Can you really be sure how much they put into your tank?

If everything is working properly, the car knows how much usable fuel it has left, and you can read that directly with Torque. I run Torque with the fuel remaining gauge. It reads out the usable fuel in gallons (from 0 to 12.5 gallons). If I were you, I would get a bluetooth OBDII adapter and Torque and start monitoring this to see if you actually have a problem and, if so, what the problem really is, whether your tank capacity is diminished for some reason or the warning is not coming on at the appropriate time.

Have you ever had the fuel pump replaced or messed with? This sounds like the fuel pump may be failing to draw fuel from the other side of the saddle. Perhaps the crossover pipe is kinked or something along those lines.

dafuq?

Clog somewhere or something? I drive mine till it has around 3-4 gallons left and pump gas. I always pump 9-10 gallons. Reset ECU?

When you pump and it clicks saying its full, check how much more you can put in as 'overfill' but really slow so that if it starts clicking every 2-3 seconds you know it is full and dont spill fuel. I can always add 3/4 gallon or so even after it clicks off.

You're not supposed to do that. From page 76 of the manual:

● Stop filling the tank after the fuel nozzle automatically clicks off
● Do not top off the fuel tank

Bad practice!!

My gf messed up some emission control stuff (breather valve? some kind of valve) in her Fiest ST by topping off the tank every time she filled up.

I've notcied that my BRZ clicks off around 3/4 gallon from full as well.

So you need to add this to the math as well, so really, if the tank is 12.5 gallons, and you cant fill the gallon almost, not leaving much to actually fill.

I will typical drive about 20 miles after the gas light clicks on, and my car will never take more than ~11.5-12 gallons

ayy guys why is this a bad practice? I'm too lazy to google (I know, ironic considering I'm the sweeper and all) and want some learnin from my ft86 brahs

Depending upon which website you believe, it is bad to top off for any of the below reasons:

1) Possibility of fuel spillage
2) If the pump is equipped with a vapor recovery mechanism, you could be increasing the cost while the fuel goes back into the station's tank. This could also damage the station's system.
3) All passenger cars produced after 2000 have an onboard refueling vapor recovery system. (https://en.wikipedia.org/wiki/Onboar...vapor_recovery) Apparently topping off can result in raw fuel getting into a system designed for vapor, causing damage to both it and the engine.

Source: http://www.epa.gov/donttopoff/ (EPA website, powered by Geocities)

I hate the EPA! buuut

#1 is definitely what I've witnessed first hand and second.. #2 also didn't think too far into!

It was most likely the charcoal canister

Do you still have the stock Purge valve solenoid connected or are you running an EBCS?

That or another part of the system @ScoobsMcGee mentioned

Wasn't my car and it was covered under warranty so I didn't look TBH

@Packofcrows listen to these guys thats a stupid practice it's called "topping it off" and I'm not sure how you haven't seen signs everywhere near the pump saying not to do that

Ding ding ding. It could be a shorter aftermarket pump so the pickup is not sitting as low in the tank as the OEM pump and thus you no longer have access to that fuel at the bottom of the tank.

^^thats it.

#firstworldproblems

Don't get angry. I was merely wondering if it (op's car) is taking what the tank is capable of or near.

11.5 Gallons as op stated means there's more or less room for 2 gallons. If he was at 2 gallons or so, he shouldn't have gone oog(out of gas). Thus, I was wondering if this problem was unique to him?

For the book, I do not advocate for topping off. Nor for letting your gas tank reach "E." Once I am bit bellow 1/4 I pump.

Not being angry lol

Sent from my A0001 using Tapatalk

Beer time then. I'll drink one for you.

:cheers:

No biggie lol

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It can lead to expensive repairs as systems that are only supposed to get vapor get drowned in raw fuel, as was stated.

I think we have a winner. I will look at that!:bow:

But the FR-S uses a 65mm body pump from the factory and I'm not aware of any aftermarket fuel pumps with shorter bodies so I'm not sure how the "shorter pump" theory is possible.

My bet is the syphon tube falling off the pump basket. With that disconnected, the pump basket doesn't get filled with fuel so as soon as your fuel level is level with the bottom of the basket - you're out of fuel. And at that level, I could see ~2 gallons remaining in the tank.

So there is one other thing that has happened that might be related and could support this theory of my aftermarket fuel pump being part of the problem. So the car has an AVO turbo and runs just over 9PSI boost. On two occasions while driving like a complete maniac, shifting from 4th to 5th, and only while going up a hill....sudden brief loss of power like no fuel. Oh...and both times I had like 1/4 tank or less of fuel. My mechanic told me he thought it was fuel slosh. Now I wonder.