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high mileage gas mileage....??


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31 replies to this topic

#1 vwbuge

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Posted 12 December 2003 - 04:39 AM

My car has a few miles on it but runs really good. Makes plenty of power and I don't burn or leak any oil to speak of. My gas mileage has dropped dramatically since I've owned the car. (I bought it with 117,000) What kind of fuel economy do you guys with high mileage Legacy's (over 200,00) get?

#2 Setright

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Posted 12 December 2003 - 07:41 AM

Average overall is 9.5 kilometers per liter. I have seen 8km/l doing 200km/h (125mph), for hours...:D And up to 13km/l doing a steady 80km/h (50mph).

One imperial gallon is 4.24 liters, and one customary gallon is 3.9 liters, to the best of my recollection.

1.609 kilometers to a mile.

#3 subieman

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Posted 12 December 2003 - 01:11 PM

Well when I bought my Legacy with 90k miles I was getting around 25-30mpg. Got 33 once. But now it has 210k on the clock and I'm lucky to get 20mpg. Summer seems to be worse with the AC on. But hey, it still runs and I love it so!!

#4 vwbuge

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Posted 13 December 2003 - 06:22 AM

I think we are in the same boat then. I remember getting 31mpg on the highway when I first bought it. I am right around 20 now also.

#5 Subarunation 713

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Posted 13 December 2003 - 08:39 AM

Just a thought on the mileage. When was the last time you changed the upstream and downstream O2 sensor?

Another thought would be an induction system cleaning. The local dealership does them for about $150. I have seen posts about some of the do it yourself products. Do a search and read up as some peopled have screwed up their catalytic converters.

Last thought is that jumping your mileage from 20 to 25 MPG may cost about $250. Other than the environment taking a hit, how much gas can you buy for $250 and how long, at a 5MPG savings, would it take to recoup that cost.

Does your county have emissions tests? and if so do you pass?

#6 patcal

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Posted 13 December 2003 - 09:39 AM

I get about 21-22 with my auto wagon. Seems pretty consistent.

#7 Commuter

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Posted 13 December 2003 - 12:01 PM

I'm at 364k km on my 97 OB, however, only 100k on the new engine.

My gas mileage has held pretty steady. It did drop off about 5% (perhaps 10% at most) over the past year. Changing the O2 sensor seemed to help. I'm still averaging about 24 or 25 mpg year round (mostly highway miles).

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#8 frag

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Posted 13 December 2003 - 02:08 PM

I second Subarumention and commuter mentions of the 02 sensor, particularly the upstream one, the one that is responsible for the ECU's metering of fuel to the injectors.
In a period of time sometimes as short as a year an 02 sensor can become sluggish and cause the ECU to enrich the overall mixture.
BUT this condition will not be sufficient to trigger a CEL.
I replaced an 02 sensor twice without a CEL already (once on the Loyale and once on the Legacy). I have had improved gas mileage each time.
I think I'm due for a new one right now.
One telltale sign the 02 sensor is maybe not up to par but not triggering a CEL is a deposit of black soot on the inside of the tail pipe. I think a very thin layer of soot is normal but if you monitor this once in a while, you'll see the difference.

My opinion based on limited private experience.

#9 patcal

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Posted 13 December 2003 - 04:03 PM

Thanks for the info. I think I will go replace mine. With 110K it could not hurt.

#10 Snowman

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Posted 13 December 2003 - 09:42 PM

Run Chevron Techron fuel additive in it for two tanks. That stuff works MIRACLES. In my mom's old subaru, the fuel economy had gone down to like 15mph. After one tank with that stuff in it, it was back up to 30 or better. I now use it religiously at every oil change. I would agree that your mileage will probably drop over time, but it definitely couldn't hurt to try this stuff, as well the changin the oxygen sensor and things.

#11 newsooby

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Posted 13 December 2003 - 09:49 PM

Does anyone have a ballpark figure on cost of replacing both O2 sensors -- independent mechanic cost not the stealer?

Thanks.

#12 99obw

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Posted 13 December 2003 - 10:44 PM

I wouldn't bother changing the downstream sensor unless you have a MIL. Supposedly it doesn't affect mileage, it just verifies the operation of the catylitic converter.

I would estimate $100 give or take for the part and $35 for the labor. If the mechanic can't do it in half an hour find a different mechanic. It is super easy to do yourself. Run the car to get the exhaust really hot and remove it with a 22mm or 7/8" wrench. It is directly under the right side inner CV joint on the new gen subies I have seen. You can get at it from near the firewall from above on the passenger side. Be careful, that stuff is hot.

FWIW I recently changed the upstream O2 sensor on our 99 outback with about 150k miles on it and saw about an 8% fuel economy improvement. I bought the universal replacement for $45 and did a little soldering.

#13 alias20035

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Posted 14 December 2003 - 03:20 AM

I was getting 30 MPIG (miles per imperial gallon) which is 10l/100km or about 25 mpg for mostly city driving on my 93 Legacy with 466,000 km on it.

It was still on the original oxygen sensor.

On the highway the mileage was about 9l/100 km or 33MPIG (26 MPG), although most of my highway mileage was with a roof rack and ski box and/or bikes attached.

#14 AusLegacy

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Posted 14 December 2003 - 06:41 AM

240,000 KM (150,000miles )on the clock and getting around 8.5km/l . Have changed my O2 sensor myself (about US$40 for the part). Didn't seem to improve fuel economy though.

I recently put some fuel additive in (one thats says that it wont clog the cat.) and power improved dramatically (near the end of the tank) Haven't calculated the mileage yet.

#15 frag

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Posted 14 December 2003 - 11:51 AM

Seems like the least one can say is that «mileage can vary».
I would then like to refine my advice (also based on limited and personal experience on two cars)
1) If no fuel mileage problem is noted, it's quiite evident that the 02 sensor has not failed...
2) I would say that if a relatively sudden drop in fuel mileage is noted, if black soot is present in the tail pipe, if the 02 sensor has not been replaced for quite a while, and if no other cause seems to explain the phenomenon, then I would test the 02 sensor or replace it outright just as a precaution. Universal ones are not very expensive and the soldering involved is quite easy.
I have access to the 02 sensor output through my Harrison's OBDscan tool. I'll check mine as soon as possible.
Mileage is horrible right now but winter is when I do mainly city driving (real downtown city driving), short distances, very cold start and use winter gas.
Anything that can improve mileage in such conditions will be welcome

#16 CROSSTBOLT

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Posted 14 December 2003 - 02:54 PM

What is a MIL?

DO NOT FORGET that in the U.S. "they" make us use MTBE wintertime additive in ALL the gasoline we buy and that struff destroys fuel economy.

#17 alias20035

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Posted 14 December 2003 - 03:21 PM

Originally posted by CROSSTBOLT
What is a MIL?

DO NOT FORGET that in the U.S. "they" make us use MTBE wintertime additive in ALL the gasoline we buy and that struff destroys fuel economy.



In Canada we used MTBE or something like it to reduce gas line icing. Between the snow tires, ski box, cold temperatures and the fuel my fuel ecomony seemed to drop only about 10-15%. Warm up idling was something I tried to avoid and it has a very significant impact to fuel economy.

MIL is a second oxygen sensor on the downstream side of the catalytic convertor to detect emmisions systems failure. Most gen2 and all gen3 Legacy's have this.

#18 frag

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Posted 14 December 2003 - 03:45 PM

alias, you must be doing mainly highway driving or city driving with long uninterrupted stretches OR you have a secret I would dearly like to know.
For summer highway driving I get around 8 liters per 100 kilometers and for winter city driving, around 15 liters per 100 kilometers (like I said short distances, at least two very cold starts each day, many stop signs and waiting at red lights, etc.) That's what I'm getting right now and the big colds are not even here yet. Further more i've just got a bottle of carbon cleaner through the gas tank. That's why I'm thinking 02 sensor.

#19 alias20035

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Posted 14 December 2003 - 04:01 PM

Originally posted by frag
alias, you must be doing mainly highway driving of city driving with long uninterrupted stretches OR you have a secret I would dearly like to know.
For summer highway driving I get around 8 liters per 100 kilometers and for winter city driving, around 15 liters per 100 kilometers (like I said short distances, at least two very cold starts each day, many stop signs and waiting at red lights, etc.) That's what I'm getting right now and the big colds are not even here yet. Further more i've just got a bottle of carbon cleaner through the gas tank. That's why I'm thinking 02 sensor.



I never touched the O2 sensor because, aside from the IAC valve problem, my check engine light never came on, the engine ran good and my fuel economy was close enough to the somewhat over enthusiastic Transport Canada ratings. My overall average was 10l/100km, dropping to under 9l/100km at best and 13l/100km at worst (rarely though).

I used to average around 11-12l/100km commuting from Hudson to downtown Montreal in winter, if that helps. Maybe traffic in Montreal is far worse than in 94-98 when I was there. I lived in downtowm Montreal for two years but never drove anywhere.

My 01 Outback gets better highway mileage but seems to drink a fair bit more fuel in the city, I now get 13.5l/100km mostly short city trips. It is a bigger engine and a considerably heavier car than my 93 Legacy.

I don't know if this helps, but I lost a lot of fuel economy due to a bad rear wheel bearing. It was a loud whine/rumble until it warmed up and then it was completely quiet. Above freezing there was no whine at all so I thought it was simply a cold diff. It sucked up an extra 2-3l/100km.

In Alberta I would cruise between Calgary and Banff at better than 130kph with a ski box (not during a chinook though with its tornado like winds in the foothills area), and still get 13l/100km or better. And this was at altitude (6,000ft) which should have a detrimental effect on fuel economy.

Perhaps the formulation of Quebec gas is significantly different than Alberta, but there is a fairly high content of ethanol in Alberta gas to deal with the Chinook temperature swings where it can go from -30C to +14C and vice-versa in just a few hours. The rapid temperature drop freezes up a lot of cars.

#20 Jub Nub

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Posted 02 June 2007 - 10:44 PM

haha! avg 23-26, mostly in town and off-road. get 30 MILES per GALLON on the freeway..... gl-10turbo wagon 5sp 3.9's

#21 kimokalihi

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Posted 03 June 2007 - 02:16 PM

90 AWD legacy wagon 4eat

25 mpg 50-55 granny driving
22.5 mpg the "old me" driving haha(before the ticket that is)

This car shows 290,000 miles on it. Runs amazing probably becuase it does not have the original engine. I don't know what happened to the engine or who put it in or anything really. No idea on the milage of the engine.

I do know that I personally installed a 94 tranny that has about 140K miles on it now I think. That was over a year ago.

The old tranny had enough and just quit working all together on the way up a big hill. RPMs shot through the roof and I started slowing down and then rolling backwards down the hill.

175 for the tranny if I had given them my core but I was too lazy so I paid another 25 bucks because I never got around to getting them my old tranny.

#22 Crawlerdan

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Posted 03 June 2007 - 02:20 PM

North West Service Currently Owns A 92 Loyal W/ 269k And I Drove It To Tacoma And Back Last Week (320 Miles) And Got 38.6 Mpg

#23 wondercow2

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Posted 03 June 2007 - 02:42 PM

Just a thought for you high-mileage/low-economy folks with autos: are you sure your torque converter is locking up consistently? That could put a big hit on your mileage.

#24 firstwagon

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Posted 03 June 2007 - 07:22 PM

My car has a few miles on it but runs really good. Makes plenty of power and I don't burn or leak any oil to speak of. My gas mileage has dropped dramatically since I've owned the car. (I bought it with 117,000) What kind of fuel economy do you guys with high mileage Legacy's (over 200,00) get?


I agree with the O2 sensor suggestions. A few years back I owned a 91 Trooper. It normally got 18 mpg (city or hwy, didn't matter). It suddenly fell to 12 mpg but no CEL. On a friends suggestion I changed the O2 sensor and right back to 18 mpg.

On my 91 Legacy, I consistently average 10 L/100km in the winter (24 mpg) and 9 L/100km (26 mpg) in the summer. Normal Hwy is 8.0 L/100 km (30 mpg) at 75 mph and all time best on a slow drive to Whistler is 7.1 L/100km (about 34 mpg?)


(B.T.W. still miss my old Trooper, best beater offroader I ever had, only weak part was the absurdly underpowered 2.8 Chevy V6.)

#25 rude

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Posted 03 June 2007 - 09:32 PM

1995 Legacy 2.2l auto, 154k

Today I did 410miles on a tank (13.5 gal) that's ~30mpg.:banana:

FWD fuse in, 70mph average, in the rain, on the mountains of the western PA turnpike (and back).

FYI:Much better than the 26mpg on a piece of junk new Kia Rio I rented in LA.


RUDE




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