Your Fuel ECON
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It could be possible it doesn't like the O2 sensor. Did you reset your ECU after these changes?Buffman wrote:I was averaging 22.4mpg mixed driving. Seems recently with the new 02 sensor it's down to 20.4mpg. Not sure why it'd go down especially after replacing a beat 155K 02 sensor. Unless the Subaru's ECU doesn't like Walker 02 sensors.
It's got a fresh tune up on it. I did put the Belt back on the AC pulley, but it's just spinning nothing as of now since AC needs new Condenser. (was getting 22 with the belt on anyways).
tires are at 35psi and are all brand new. Everything else is running good... I would have figured it would get better mpg.
If not, turn all accessories off, disconnect the battery for 45+ minutes, reconnect, start the car and don't touch anything, especially the throttle! Let it idle until it reaches operating temperature (~15 minutes depending on weather) then turn it off. Now you ECU has a clean slate to relearn the normal ranges of its operating conditions.
-Nick
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
yeah I reset the ECU after recording those Mpg. Funny thing was this week it shot back up to 24.5 mpg with about the same driving. I'm not sure if it doesn't like idling as I did work on it this weekend (trans fluid change and coolant drain and refill) and mpg is back down to 21.4 mpg.
I thought I read people had good luck with walker 02s on here, hence why i went with them.
I thought I read people had good luck with walker 02s on here, hence why i went with them.
1992 Legacy LS Special Wagon..
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I think the ECU has adapted for the good run you got. Did you reset it again, perhaps causing the poor mileage?
-Nick
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
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- First Gear
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hmm. according to online calculators, i'm getting 23.5 mpg. i get around 10km/L.
all city driving, with warming the car up before driving it, 4eat turbo, fresh motor and its winter right now. oh and its intercooled, and has open atmosphere crankcase and cyl head catch can setup.
all city driving, with warming the car up before driving it, 4eat turbo, fresh motor and its winter right now. oh and its intercooled, and has open atmosphere crankcase and cyl head catch can setup.
Last edited by juice91si on Fri Dec 05, 2008 2:08 am, edited 1 time in total.
Summer Fun = 1991 Civic Si Turbo
Winter Fun = 1991 Legacy Sport Sedan
Winter Fun = 1991 Legacy Sport Sedan
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ummmmmm. so upon further mathematical breakdowns, i appear to have made an error.
i think im getting more like 13mpg. WTF.
well it sort of makes sense..i have a slight fuel leak and let the car idle for a long time before driving it. either way it sucks getting worse gas mileage than a v8 truck.
i think im getting more like 13mpg. WTF.
well it sort of makes sense..i have a slight fuel leak and let the car idle for a long time before driving it. either way it sucks getting worse gas mileage than a v8 truck.
Summer Fun = 1991 Civic Si Turbo
Winter Fun = 1991 Legacy Sport Sedan
Winter Fun = 1991 Legacy Sport Sedan
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I haven't ever got that bad, but I don't get that great either. The worst I've got on one tank is 15.8 mpg, which included long idling, short 1 mi trips to school, and doing doughnuts in parking lots.
My two year average is 22.8
My two year average is 22.8
-Nick
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
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With roof rack and studded snow tires, I get about 25-26mpg highway. Before I put the roof rack on, I could sometimes get 30-31 on long highway trips, but the best I've got since the roof rack was 29.
Not as nice as the 30-32 I used to get in the gasoline Jetta, or the 45 I used to get in the diesel Jetta, but neither of those could handle the snow quite like the Subaru does..
Not as nice as the 30-32 I used to get in the gasoline Jetta, or the 45 I used to get in the diesel Jetta, but neither of those could handle the snow quite like the Subaru does..
1990 Legacy wagon, 340k miles, rusted out and retired to parts car status
1991 Legacy wagon, 232k miles
1994 Legacy wagon, 146k miles
1992 Dodge/Cummins W250 flatbed, 294k miles
1976 Mercedes 240D
1977 Mercedes 240D, 230k miles
1991 Legacy wagon, 232k miles
1994 Legacy wagon, 146k miles
1992 Dodge/Cummins W250 flatbed, 294k miles
1976 Mercedes 240D
1977 Mercedes 240D, 230k miles
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I think the lowest I ever got was about 22 and part of that tank was spent crawling around on dirt roads in the mountains.
I was kind of feeling like 25 wasn't very good until I read this thread...
I was kind of feeling like 25 wasn't very good until I read this thread...
1990 Legacy wagon, 340k miles, rusted out and retired to parts car status
1991 Legacy wagon, 232k miles
1994 Legacy wagon, 146k miles
1992 Dodge/Cummins W250 flatbed, 294k miles
1976 Mercedes 240D
1977 Mercedes 240D, 230k miles
1991 Legacy wagon, 232k miles
1994 Legacy wagon, 146k miles
1992 Dodge/Cummins W250 flatbed, 294k miles
1976 Mercedes 240D
1977 Mercedes 240D, 230k miles
Worst mileage I got on the SS was about 15mpg, best I got was 24MPG mixed mostly H/W but the SS had the EJ20G in it then (it was & still is 4EAT).
My '99 OBS-t phase II 2.2l gets over 30-33MPG regularly on the highway & about 20-22MPG in the city.
The wife's '96 OBS phase I 2.2l 4eat gets about 18.8 MPG in the city recently & about 26-27 MPG on the HW based on the last 3 fill-ups.
It did much better MPG in the summer for some reason.
My '99 OBS-t phase II 2.2l gets over 30-33MPG regularly on the highway & about 20-22MPG in the city.
The wife's '96 OBS phase I 2.2l 4eat gets about 18.8 MPG in the city recently & about 26-27 MPG on the HW based on the last 3 fill-ups.
It did much better MPG in the summer for some reason.
94 Legacy SS
96 Impreza OBS
99 Impreza OBS-T
04 Sienna XLE Limited AWD
96 Impreza OBS
99 Impreza OBS-T
04 Sienna XLE Limited AWD
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Winter gas sucks. I think it's a higher ethanol content, but whatever it is that they add to it, I go from 30 mpg to 27 in the Mazda and you can tell from the first fill up when the stations change over.
Midnight in a Perfect World on Amazon or order anywhere. The first book in a quartet chronicling the rise of a man from angry criminal to philanthropist. Midnight... is a distopic noirish novel featuring 'Duchess', a modified 1990 Subaru Legacy wagon.
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mpg poll
STi block w/ 2.2l heads N/A 5 spd manual AWD
24-27 MPG
24-27 MPG
1991 Subaru Legacy BJ 2.2L/2.5LSTi Block Hybrid N/A w/ over 250,000 miles! 1992 Yamaha Seca II 2004 Dyna Super Glide My other car is a Go Kart Redhair...Black Leather...My favourite colour schemes. If it's not Scottish...it's Crap!
Avg: 20mpg
Best: 23mpg
Car: 1992 SS, big 16g, '06 TMIC, 3" turbo back, Delta Cams, Ported Heads. Tuned to 200whp/200wtq @ 11psi max boost w/ low (<15%) throttle fueling the same as stock.
Explanation:
Living in a somewhat rural area, my driving consists of about 70% country roads (curves, hills, some downhill sections that i can coast on)
about 20% freeway, and the remaining 10% is stop and go signal action.
I get about 20mpg, so basically I fill up every 220miles of NORMAL driving with a few sprints here and there.
Although I can get up to 23mpg on the freeway IF and only IF I lean out the A/F ratio with my fuel controller. I don't risk this on the streets because if I ever need to actually accelerate my engine would go pop-bang and I'd be sad.
Best: 23mpg
Car: 1992 SS, big 16g, '06 TMIC, 3" turbo back, Delta Cams, Ported Heads. Tuned to 200whp/200wtq @ 11psi max boost w/ low (<15%) throttle fueling the same as stock.
Explanation:
Living in a somewhat rural area, my driving consists of about 70% country roads (curves, hills, some downhill sections that i can coast on)
about 20% freeway, and the remaining 10% is stop and go signal action.
I get about 20mpg, so basically I fill up every 220miles of NORMAL driving with a few sprints here and there.
Although I can get up to 23mpg on the freeway IF and only IF I lean out the A/F ratio with my fuel controller. I don't risk this on the streets because if I ever need to actually accelerate my engine would go pop-bang and I'd be sad.
Last edited by Imprezive on Tue Mar 24, 2009 5:19 am, edited 1 time in total.
1992 T-Leg = 195whp 197wtq SOLD :(
1988 4Runner RIP
2006 Suzuki DRZ400sm
2007 Miata
1994 Miata
2003 WRX Wagon
2016 Mazda 3
1988 4Runner RIP
2006 Suzuki DRZ400sm
2007 Miata
1994 Miata
2003 WRX Wagon
2016 Mazda 3
I was having this problem lately and replaced a bunch of sensors. I am currently awaiting the results from this tank of gas. It was sucking really bad so i had to find the problem, hopefully I did as though I finally got the CEL to go off and stay off! The longest since i have owned the car and that is 6 years now. It is a 91 22t 4eat, the poor mileage had only started recently though.juice91si wrote:ummmmmm. so upon further mathematical breakdowns, i appear to have made an error.
i think im getting more like 13mpg. WTF.
well it sort of makes sense..i have a slight fuel leak and let the car idle for a long time before driving it. either way it sucks getting worse gas mileage than a v8 truck.