My 96 Legacy GT (2.5l) is getting relatively poor fuel mileage (aprox 20Mph in
It did throw a CEL a while ago but it hasn't come back after the codes were cleared due to a battery replacement.
I suspect the O2 sensors being old and "lazy" and needing replacement.
Is there a reference for average or out-of spec values of O2 sensors? E.g.: rich- lean switch times, low and high voltage etc. etc.
florian
Some trouble codes don't trigger the CEL. You could do a code scan and see what comes up.
If they're old, might as well replace 'em. Might not hurt to see what the trouble codes are first though. Wouldn't want it to be something that would foul the new O2 sensors.
No codes are stored - that's the problem.
I don't really know how old they are. I bought the car at 140k miles. I'd like to compare their output to what typically is within spec before throwing out a pair of perfectly good O2 Sensors.
What else causes a significant hit in fuel efficiency (can't be my right foot alone, I got 26Mpg out of my 2.2l Legacy before)?
Florian
For winter blends of fuel and temperatures, your mileage is close to my 96 Outback 2.5l. If you are in California, there might be other issues (like the emissions control system). The best I have ever gotten in warm weather at constant highway speed is about 28. In winter (Nebraska) I average about
It's definitively downhill from here and worse than I had thought. On of the last tank fills - after mostly city driving - came to under 17Mpg.
I think the car is definitively running too rich.
Can someone here tell me what values to expect from a "healthy" O2 system in a Legacy?
The post-cat sensor indicates a max sensor voltage of 0.000 (?) and a min of 1.
275... no lean-rich switch time at all among other missing values. The pre-cat sensor behaves relatively normal oscillating between 0.8V. Could that mean the cat is cooked?florian
Good idea - but the OBD II scan tool shows the coolant temp/ relatively steady at approx/ 185F.
Filled the car up again on Saturday and got 160 miles out of 15 gallons. Feels like I am driving a Jeep Wrangler :(
florian
Is gas leaking out somewhere while you drive?
Nope, except through the combustion chamber obviously :)
Seriously, if that were the case I'd expect a strong smell of raw gas from under the hood after stopping the car. No such thing though.
I'll try new O2 sensors next - I was only hoping someone with an OBD2 scan tool could share with me his/her readouts from a working emissions control system.
florian
Either something is telling the ECU to richen the mixture or something (like an injector) is failing to control the fuel. Try looking at the plugs for one that is different from the others. That cylinder could have a bad injector I guess. Not sure the 185 you're reading is from the same sensor the ECU uses for engine temp. On soobs there are 2 different sensors, near each other, on the coolant xover. Anyway good luck.
Carl
1 Lucky TexanFlorian Feuser /FFF/ wrote:
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