jcniest5 Posted July 16, 2004 Share Posted July 16, 2004 Guys, I've posted on other threads about getting a less MPG on my '91 Legacy AWD non-Turbo Auto but so far no one has answer my question specifically, so here I am forced to ask again. I need to know what is really wrong with my car. Okay, here's what I've done so far: Replace Plugs, Wires, new air filter, use Fuel two cans of Injector cleaner. Instead of improving, I think it's actually getting worse. I can actually see my gas gauge meter moving! The only thing I can think of replacing is the oxygen sensor. I mean a 4-cylinder engine can't drink this much gas! I used to get 20-25 mpg before. Now, I'm down to 12-15 mpg. And it is getting worse! Please, please, please, your hints and assistance will greatly be appreciated! Thanks in advance... JC Quote Link to comment Share on other sites More sharing options...
SkiGuyGT Posted July 16, 2004 Share Posted July 16, 2004 12mpg? Wow thats not normal! I think you have some major problem, probably with the ecu or a sensor, maybe something else, who knows. I'd probably take it to a place and have them figure it out, maybe you can just do it yourself after you learn whats wrong. Man, that makes my 19-25mpg look awesome. Quote Link to comment Share on other sites More sharing options...
Adam N.D.J. Posted July 16, 2004 Share Posted July 16, 2004 Ya ya ya, try getting 6-8 mpg with a 10 gallon tank! Quote Link to comment Share on other sites More sharing options...
LosDiosDeVerde86 Posted July 16, 2004 Share Posted July 16, 2004 Guys, I've posted on other threads about getting a less MPG on my '91 Legacy AWD non-Turbo Auto but so far no one has answer my question specifically, so here I am forced to ask again. I need to know what is really wrong with my car. Okay, here's what I've done so far: Replace Plugs, Wires, new air filter, use Fuel two cans of Injector cleaner. Instead of improving, I think it's actually getting worse. I can actually see my gas gauge meter moving! The only thing I can think of replacing is the oxygen sensor. I mean a 4-cylinder engine can't drink this much gas! I used to get 20-25 mpg before. Now, I'm down to 12-15 mpg. And it is getting worse! Please, please, please, your hints and assistance will greatly be appreciated! Thanks in advance... JC did you check all of the gas lines to make sure there's no leaks? also the fuel filter might need to be replaced....maybe... Quote Link to comment Share on other sites More sharing options...
jcniest5 Posted July 16, 2004 Author Share Posted July 16, 2004 did you check all of the gas lines to make sure there's no leaks? also the fuel filter might need to be replaced....maybe... No leak anywhere. The smells when you first start the engine is somewhat alarming, though. Instead of the natural smell of gas fume coming out of the exhaust pipe, it smells more like real gas mixed with the fume. If I can remember it correctly, the smells should be plain fume with not real gas odor. Also, can a fuel filter cause my engine to drink more gas? I thought it only prevents it from having a free-flow operation but not makes the engine drink more gas. That's just my understanding. I guess if I have to, then I will replace it as well. For some reason, I really believe it's the oxygen sensor, but who knows if I'm right or wrong. Quote Link to comment Share on other sites More sharing options...
Tiny Clark Posted July 16, 2004 Share Posted July 16, 2004 Is there a good amount of exhaust pressure at the tail pipe? Maybe you have a blockage of some type, or damage to a pipe somewhere. If it seems to be idling OK, the only other thing I can think of is the ECU screwing up the timing real bad. Is there a knock sensor on this car? I am surprised you are getting no fault codes. Quote Link to comment Share on other sites More sharing options...
jcniest5 Posted July 16, 2004 Author Share Posted July 16, 2004 Everyone once awhile, I would get a Check Engine light. It would go away after 5-10 minutes of driving. Then it would be gone for months if not longer. Everytime I hose the engine with water, the Check Engine would also come on until the engine is complete dry (usually after 30 minutes of driving on highway). I reset the ECU and it would go on for months (and longer) without the Check Engine light. I'm very puzzling... Edit/add: Could it be that I've switched the tires from 175 to 185? The tires for the car were 175/70R14 but ever since I've bought the car, I chose the 185/70R14. Also, they are supposed to rate H but I opted for the S rating for cost effective. Could my decision to go with cheaper tires be the culprit of my poor gas MPG? Quote Link to comment Share on other sites More sharing options...
Setright Posted July 16, 2004 Share Posted July 16, 2004 The stock size on my Legacy was 185/70R14, and it didn't drink like that. I even upped them to 195/60R15, and didn't notice any serious drop in mpg. However! This car is too heavy to sit on S rated tyres, and this will affect your mileage. So, I would strongly recommend going back to H or better. Even so, even crappy, deflated tyres won't make your exhaust smell like gasoline. So, you certainly have another problem. Remove your air filter box and check the MAF sensor for dirt/debris which could give a faulty reading. The problem might be related to the ECU thinking it is drawing in more air than it actually is. I would expect the O2 sensor to complain, but maybe that's gunged up too? Come to think of it, a clogged catalyst won't help milage either. Quote Link to comment Share on other sites More sharing options...
hawksoob Posted July 16, 2004 Share Posted July 16, 2004 Also, can a fuel filter cause my engine to drink more gas? I thought it only prevents it from having a free-flow operation but not makes the engine drink more gas. That's just my understanding. I guess if I have to, then I will replace it as well. I've always heard that if you use a fuel system cleaner, especially after not having ever done it or if it's been a really long time since it's been done, it's a good idea to change the fuel filter. That cleaner can free up a lot of crud and gunk which can clog up the fuel filter. Quote Link to comment Share on other sites More sharing options...
jcniest5 Posted July 16, 2004 Author Share Posted July 16, 2004 You mean the sensor that looks like some of kind of needle located just past the air filter housing? I think the last time I took it out or opened it (a week ago), it is was clean. But I will check it again. I will also check the air pressure coming out of the exhaust pipe. Oxygen sensor is my next item to be replaced. Any idea where I can get cheap OS2? Edited/Added: Can you unplug the MAF connector without the engine dying? On mine, if I unplug that connector, the engine dies immediately. Won't it suppose to run even when the connector is unplug, but just runs really crappy? Those of you who have time, please help me by unplugging your MAF sensor connector and see if your engine dies immediately, too. If not, I think my ECU may be the culprit. Quote Link to comment Share on other sites More sharing options...
kevinsUBARU Posted July 16, 2004 Share Posted July 16, 2004 Quote Link to comment Share on other sites More sharing options...
Setright Posted July 16, 2004 Share Posted July 16, 2004 Unplugging the MAF should kill the engine. I can't really test it on my car, cause I have the newer, cheaper, crappier MAP sensor.!!! By the way, don't touch the MAF sensor thread/needle !!! Just look at it... Quote Link to comment Share on other sites More sharing options...
SevenSisters Posted July 17, 2004 Share Posted July 17, 2004 No offense but S, H, V, or any other speed rating has nothing to do with the tire's load rating, the little number next to the speed rating on the sidewall. As far as the poor fuel economy goes, if you were burning all that gas I think you would get a code to warn you that you're screwing up our air. So think leak some more. Low tire pressure, dragging brakes, check'em out too. I had a bad fuel injector that must have sprayed a ton of gas. Even then, the fuel economy didn't drop that much. It didn't set a code 'till it got real bad. Exhaust smelled like burning vegitation. Thought I had a mouse nest in the tail pipe that wouldn't burn out. Kept getting worse and then a code for the number 3 injector came on. Good luck and keep us posted. Quote Link to comment Share on other sites More sharing options...
jcniest5 Posted July 17, 2004 Author Share Posted July 17, 2004 I used Throttle Intake cleaner and blasted that needle (MAF sensor) thing off earlier this morning. I will have to keep an eye on my mpg to see if it makes any difference. Edited/Added: Just got new tires, and brakes are all working fine, no dragging or unexpected braking affect. BTW: How much are injectors anyway? Quote Link to comment Share on other sites More sharing options...
JonOfScio Posted July 17, 2004 Share Posted July 17, 2004 Well, our O2 sensors aren't one wire, so they aren't "cheap" per say, but I can't give you a quote because I don't know what they run. I got about 20 mpg, and did these things... fuel filter pcv valve new drain plug k&n oil filter synthetic 5/30 switch cleaned the MAF sensor and now I'm getting 30mpg. although your O2 sensor *may* be out too. To clean the maf sensor, disconnect it from the intake and the airbox. carefully of course. then use electrical parts cleaner... clean it out that way, and let it dry. put it back in (carefully) and make sure everything is tight. Quote Link to comment Share on other sites More sharing options...
jcniest5 Posted July 17, 2004 Author Share Posted July 17, 2004 PCV Valve, when you can hear the click, is that still good? Is there even a definite good or bad sign when testing it? Quote Link to comment Share on other sites More sharing options...
jcniest5 Posted July 17, 2004 Author Share Posted July 17, 2004 Also, just changed oil about 1K miles back with Durablend 10-30W oil. FYI: It's sythetic blend, so it's not complete sythetic. Quote Link to comment Share on other sites More sharing options...
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