running out of gas too early?

[idosubaru]

2002 OBW H6. Runs and drives great.

 

Ran out of gas and it only took 14.2 gallons - supposed to have a 16.9 gallon tank.

 

Drove 19 miles after the low fuel light came on.

 

I realize I can get gas sooner but at the same time this isn't like any other Subaru I've ever driven.

 

Don't recall the gas tank being dented or anything.

[SuBrat84]

I wouldn't be surprised at all if the low fuel light is coming on with ~3 gallons left in the tank. depending on how the bottom of the tank is shaped it might not be able to pick up ANY gas with a gallon in there still.

[heartless]

it is actually quite common for a vehicle to show "empty" but still have a gallon or more left in the tank.

 

not really relavant to a car, but on a semi the guage can read empty, and even have trouble starting with more than 20 gallons left in the tanks (keep in mind that they usually hold 100 gals or more) all depends on the length of the pick-up tubes.

[johnceggleston]

i think they are 15.9 gal tanks, but that does not explain your problem. the pick up tube may, but this is not a new to you car is it? you've had this a while. seems like you would have run into this earlier.

 

it would be interesting to know if both sides of the tank are the same. i seem to remember that the passenger side is larger but i don't really know. maybe the ''siphon pump'' from the driver side failed.

 

any chance the pump cut off early? did you try to add a little after it first cut off? (i know this is not recommended but mine takes about .2 gals after it first shuts off. i do this on long trips some times.) some pumps cut off when the other guy's pump shuts off, it seems.

[NorthWet]

I seem to recall a couple years back someone was talking about difficulties getting a complete fill on an empty Legacy-class vehicle. (Gary, I assume that you have searched already, but thought that it was worth the mention.)

 

I assume that your car has the saddle-style gas tank. I have not looked at one, but wonder how quickly gas fill flow between the 2 sides while filling. Maybe the height of the structure of the tank and filler position/height are causing the pump to shut off before the opposite tank saddle fills fully.

[idosubaru]

it is actually quite common for a vehicle to show "empty" but still have a gallon or more left in the tank.

right, those gauges aren't that accurate or meaningful. let me clarify what i'm asking.

 

I wouldn't be surprised at all if the low fuel light is coming on with ~3 gallons left in the tank..

all Subaru owners manuals tell you how much fuel is left in a tank when the low fuel light comes on - it's usually about 2.5-3.0 gallons. that's standard, known information. and i'm an engineer so i've tested the limits.

 

every other subaru i've ever owned (only been about 30 ) is completely calculable how much you can drive. 2.5 gallons left at 20 miles per gallon (low estimate) - you can easily go 50 miles in any subaru when the low fuel light first comes on. i've done it a thousand times in all sorts of different soobs....just be careful if you're towing, roof racks, bike, etc, 80mph, you might not be getting 20mpg.

 

depending on how the bottom of the tank is shaped it might not be able to pick up ANY gas with a gallon in there still.

hmmm, yeah maybe it's something like that - wonder how it works or what could be different so i can understand what's going on.

 

JCE - most subaru's have a 15.9 gallon tank - i believe the OBW H6 has a 16.9 (the extra gallon apparently didn't help. )

[GeneralDisorder]

I recently had a legacy where the filter/tube on the end of the pump was AWOL due to an aftermarket fuel pump replacement. Guess they didnt think they needed it. That left it with about 4" less pickup and it would die on hard right turns when it was low. Something to investigate. I would pull the pump and inspect.

 

GD

[bheinen74]

my BAJA manual says 16.9 gallons. Should be exact same as the Outback Wagon of year 2000-2004.

[SuBrat84]

I don't know how much you can account for fuel expansion.. but maybe putting 14 gallons of COLD fuel into a WARM vehicle made the fuel expand enough to make a little bit of a difference? Not likely, just a thought. (On the motorcycle forum I'm on: a guy filled his motorcycle tank to the tippy top.. and then parked it.. and the heat from his engine made his fuel spill out of the top of his tank.) I like the idea about the saddle/air bubble thing. I've been known to throw a little extra fuel into the filler neck if I know I'm going to be driving it off right away. And it definitely 'settles' a little bit after the initial shut off.

[Fairtax4me]

Made it expand 2 gallons? It's not Great Stuff.

 

I agree, inspect the broken/detached pickup tube theory.

The siphon pump theory sounds plausible as well.

[idosubaru]

I recently had a legacy where the filter/tube on the end of the pump was AWOL due to an aftermarket fuel pump replacement. Guess they didnt think they needed it. That left it with about 4" less pickup and it would die on hard right turns when it was low. Something to investigate. I would pull the pump and inspect.

 

GD

 

nice hit, that's what it must be then. this happened once before, so it's seemingly repeatable. i'm confident assuming it's not electrical or something wacky and don't have the time any time soon. assuming there's little possibility of it hurting anything?

 

thanks all.

[GeneralDisorder]

I don't think it will hurt anything to leave it for a while. Takes about 20 minutes to pull the pump. I got a used assembly and replaced the whole thing - easier than fussing with that filter.

 

GD

[bheinen74]

maybe somebody took your car to Mexico hid the stash in the tank and forgot to remove before they sold the car to you? jk, but that is a remote possibility.

[idosubaru]

I don't think it will hurt anything to leave it for a while. Takes about 20 minutes to pull the pump. I got a used assembly and replaced the whole thing - easier than fussing with that filter.

20 minutes, that's it? interesting, maybe it's worth a look some day.

 

"filter" - is there a filter on it - like a sock of some sort like the older gen fuel pumps have?

 

maybe somebody took your car to Mexico hid the stash in the tank and forgot to remove

okay, i will pull it.

[GeneralDisorder]

Yeah - pull back the carpet and its like 10 nuts and the whole assembly pulls out of the tank. The pickup has a flat, square nylon mesh "bag" that I guess you could call a sock of sorts. Some carpet, nuts, few hoses, and a couple connectors. No big deal on a Subaru unlike most cars where you must drop the tank.

 

GD

[NorthWet]

Yes, it is pretty easy to pull the pump assembly. Biggest issue in my mind is pulling the fuel lines loose off of the pump fittings: space is a little tight. But, you do get the perk of doing it in the comfort of the car instead of crawling underneath.

[idosubaru]

if that mesh "bag" fell off then maybe it's worth fixing it so it's not sucking up unrestricted stuff from the tank?

 

so all that stuff comes as an assembly if you buy a fuel pump? you get those new or used? i think they're really steep from subaru aren't they - someone just said $800 or something in another thread recently, unless that was labor too?

[GeneralDisorder]

I just get used ones personally. There are plenty of suppliers that sell just the pump - some of them come with the pickup/bag. And yes theres nothing keeping it from sucking debris without the pickup.

 

GD

[idosubaru]

How many parts could be lying in the tank somewhere? Haven't seen an EJ pump before so not sure what all to look for when I take it apart.

 

Just the mesh box thing or is there a separate hose/clamps too?

 

So do this with a low gas tank!?

[Manarius]

The low fuel light on my car comes on with 5-6 gallons left in the tank