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Old 01-06-2009, 01:21 AM   #1
TurboCharged97L
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Default outback terrible mpg's !!!!!!!!!!!

okay so i just picked up a 1997 legacy outback limited auto. I have changed all the tranny/diff fluids, oil change, fuel system cleaner, cleaned my battery terminals, and bought a new air filter. The car is completely stock with 148k on it:

1. I am only able to fill up with 12 gallons even though the manual claims I have a 15 gallon tank

2. Even if it is only a 12 gallon tank im getting 200 miles on that and thats only like 16 mpg which is terrible, I could have bought an suv instead

I really love this car and intended on keeping it for a very long time especially since the car has the headgaskets changed, new timing belts, valve cover gaskets, water pump, and everything in the car works. I am going to give it a tune up next week (plugs, wires, fuel filter) but I can't imagine a tune up will give me 100 more miles to the tank. I drive alot and this car would really not be functional to keep so I will have to sell it if I cant fix this problem. If this is typical mpg for an outback consider it for sale.

so all in all is this typical fuel economy for the outback ? and what else can I try and fix to solve this? (there are no check engine lights)
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Old 01-06-2009, 02:29 AM   #2
chazly413
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What are your driving habits like? And you'd have to be drive for a bit with the fuel low light on to get anywhere near pumping 15 gallons into there. The most I've ever pumped in *may* have been 13 gallons into my 16 gallon tank.

It's possible the tune up may free up a good bit of MPGs if that stuff has not been changed in a while.
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Old 01-06-2009, 08:58 AM   #3
Pohenegamook
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yea - there's always a few gals in the tank unless you run it bone dry and never calculate 'by tank'.

Here's what I do: Next time you fill up, zero out your odometer (hopefully you have 2 like newer imprezas - I use one for gas the other for oil changes.) Then the time after that fill it up again and look at your receipt and do the math (e.g. 265 miles on the odo / 12 gals = 22.1 MPG)

in my 06 OBS - get between 22-29 MPG, highway miles and driving habits greatly impact my mileage.

edit: since you cleaned your terminals, I assume you disconnect the battery. It may take a tank or 2 for the ECU to get back to optimal mode. Also, reset the ECU again when you do the tune up (my not help but won;t hurt)

Last edited by Pohenegamook; 01-06-2009 at 09:27 AM.
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Old 01-06-2009, 09:31 AM   #4
FabFlatFour
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On my Impreza I've noticed that cold starts have greatly reduced my average fuel consumption from 9.8 L/100kms to 12.2 L/100kms. Also, my tire pressure has affected it a bit too, it's been low for a little while (sloshy driving). Those could be contributing factors to your mileage?
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Old 01-06-2009, 12:32 PM   #5
TurboCharged97L
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well I drive this car like a grandmom and whenever im on the highway im doing 65 in cruise control I have never pushed it past half throttle which is why im concerned about my mpg's. And I reset the trip meter every time I fill up and last time I was on E I filled up with 11.80 gallons and then when I was back on E I had went 205 miles. 205/12 = 17.08. Which is pretty bad I would say since the car is rated at 22 city and 29 highway. I just really hope this isnt normal
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Old 01-06-2009, 01:19 PM   #6
sniper1rfa
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Don't use "E". Use the volume of gas metered by the gas pump and your odometer. Ignore the gas guage, they are generally pretty useless beyond "oh, my tank doesn't have a lot of gas in it".


So, reset the odometer when you fill up. Drive a bunch, fill up again, note how much gas you put in and your odometer reading. Use those numbers to calculate fuel economy.

If it's still less than 20, something's wrong somewhere, either with the car or with your driving habits.

EDIT: by the way, cruise control is generally quite inefficient. If you want to get good efficiency, learn to train your right foot to stay in one spot, roll fast down hills and creep up them. Going up mountainous regions is just going to be very inefficient (dunno if you have mountains where you're at).
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Old 01-06-2009, 01:40 PM   #7
kero
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My 07 2.5i wagon, I get really sucky gas mileage but honestly, I drive it a little hard, I like to listen to my exhaust

For subies, driving habbits really make a huge difference in gas mileage!
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Old 01-06-2009, 01:41 PM   #8
watchunglava
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hell yea closed loop
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Old 01-06-2009, 02:06 PM   #9
steeter
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Front O2 sensor maybe? There doesn't have to be a CEL for it to be bad.

-S
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Old 01-06-2009, 03:54 PM   #10
yarrgh
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if the temp sensor is going out, it may keep the ECU in startup mode, which is really rich. but the front O2 sensor can also be a culprit. try changing brands of gas. or octanes.
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Old 01-06-2009, 03:58 PM   #11
cdwahl
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I would definitly change the spark plugs, fuel filter and the o2 sensor(s). Should see mileage go up at least a little bit.
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Old 01-06-2009, 07:23 PM   #12
rhino6303
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Another thing to consider is a roof rack and/or attachments. I have a MY05 OBS with a Yakima rack and a snowboard attachment. With just the rack, I see my mileage decrease from 28 mpg avg. to 24 mpg avg. (a lot of highway miles). With the rack and snowboard attachment, I see my mileage decrease from 28 mpg avg. all the way down to about 20 mpg avg. My point is this: if you have a rack, and the car needs a tune-up, I could easily see only 17 mpg.
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Old 01-06-2009, 08:05 PM   #13
Matt Monson
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What octane fuel are you using? Yes, it's a loaded question...
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Old 01-06-2009, 11:27 PM   #14
TurboCharged97L
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no racks, no attachments just standard cross bars, I use 87 octane. should I be using something higher?
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Old 01-07-2009, 12:55 AM   #15
ronoverdrive
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Try doing a full tune up (wires, plugs, distributor cap, belts), fill the tank with high octane for one go, and throw in some injector cleaner. See if it helps.
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Old 01-07-2009, 01:23 PM   #16
Matt Monson
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Quote:
Originally Posted by TurboCharged97L View Post
no racks, no attachments just standard cross bars, I use 87 octane. should I be using something higher?
Nope. That's the right answer. I asked the question because many people mistakenly put premium in that car. The 1996 required premium, but the '97 did not.

If your plugs are fresh, I would suspect the front O2 sensor or a cat. that's on it's way out.

However, really your mileage isn't that far off where it should be. You are maybe 2-3mpg off what I would expect out of that car.
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Old 01-07-2009, 01:24 PM   #17
Matt Monson
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Quote:
Originally Posted by ronoverdrive View Post
Try doing a full tune up (wires, plugs, distributor cap, belts), fill the tank with high octane for one go, and throw in some injector cleaner. See if it helps.
Ej series Subarus don't have distributors or distributor caps.
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Old 01-07-2009, 01:48 PM   #18
ronoverdrive
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Quote:
Originally Posted by Matt Monson View Post
Ej series Subarus don't have distributors or distributor caps.
It was 1AM and I wasn't all there. Ended up spouting general tune-up stuff.
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