Markus56 Posted February 26, 2012 Share Posted February 26, 2012 Hello all, My 91 Legacy is getting terrible gas milage. I've been keeping track and i am only getting about 100 miles to a tank of gas during in town driving. What sort of things could be causing this? I have my tires set at 35 psi, cleaned the maf, am running non ethanol fuel, and seafoamed the gas and oil. Also, the exhuast does not smell rich, and there are no fuel leaks. What the heck Link to comment Share on other sites More sharing options...
nipper Posted February 26, 2012 Share Posted February 26, 2012 drop the 100 miles per tank, give us real MPG first. Link to comment Share on other sites More sharing options...
MilesFox Posted February 26, 2012 Share Posted February 26, 2012 How is the exhaust? It may look intact, and sound extra subaruey, but look for a split in the muffler seam, especially the other side you have to crawl under the car to look at. My 95 legacy is getting under 18mpg, blasting through 1/4 tanks per day doing local errand urban daily driving. It has an open exuahst with no muffler. I chopped in a cherry bomb at the center section and straight piped the rear out past the bumper. The car moves better and isn't choking me on exhaust fumes. Hopefully the mileage improves. The 94 legacy blew its muffler out and dropped in fuel economy. On 300 mile highway driving, she averaged 24 mpg this way. I chopped off the muffler and installed a cherry bommb, and he does about 26 mpg on the same trip. But now the heat sheilds fell off, and the post-cat header pipe rusted through at the pipe hanger. She is averaging 16 mpg in-town urban delivery driving. We have 10% ethanol blend fuel. Link to comment Share on other sites More sharing options...
Markus56 Posted February 26, 2012 Author Share Posted February 26, 2012 Exhaust is all intact except where i chopped the muffler and put in a glasspack. She has all the heat shields too. Its a Washington car that has no rust whatsoever Link to comment Share on other sites More sharing options...
nipper Posted February 26, 2012 Share Posted February 26, 2012 Again mathmatical mpg please. And no where on your list is tuneup which should have been step 1 Link to comment Share on other sites More sharing options...
Markus56 Posted February 26, 2012 Author Share Posted February 26, 2012 (edited) yes, complete tune-up, from plugs to pcv, 1/4 tank of gas to go 15 miles. so 14 gallon tank. 3.5 gallons into fifteen miles. 4.2 mpg. Also, its an automatic, which i have 100% flushed, and replaced both filters and added an extra tranny cooler. and i have 215/75r15 size tires. Edited February 26, 2012 by Markus56 Link to comment Share on other sites More sharing options...
nipper Posted February 26, 2012 Share Posted February 26, 2012 Gas gauges are notorious for being innacurate on subarus. My tank reads E at 9 gallons. Do it mathmatically with real gallons from a so we know what numbers we are dealing with. Link to comment Share on other sites More sharing options...
Markus56 Posted February 26, 2012 Author Share Posted February 26, 2012 k. when the gauge read a hair above E it gets 13.5 gallons, so that what i am basing this off of, but i will go and fill up real quick to get some exact numbers, should take about 30 mins. and i have been keeping track of mileage too. Link to comment Share on other sites More sharing options...
nipper Posted February 26, 2012 Share Posted February 26, 2012 I would prefer you go through a tank of gas then tell us. Unless your tank is low it wont be a valid enough reading. Link to comment Share on other sites More sharing options...
Markus56 Posted February 26, 2012 Author Share Posted February 26, 2012 Ok. I've driven 82 miles since last fill-up and i just put in exactly 6 gallons at the pump. 13.6 mpg. Although i have no idea how i drove 82 miles. Especially when the town i live in is 3.5 miles square. Link to comment Share on other sites More sharing options...
Markus56 Posted February 26, 2012 Author Share Posted February 26, 2012 I would like to drive through the whole tank, but its only two miles to work and back, and the nearest population center is 102 miles south, and i have no reason to go there :-p Link to comment Share on other sites More sharing options...
Red92 Posted February 26, 2012 Share Posted February 26, 2012 and i have 215/75r15 size tires. Ok. I've driven 82 miles since last fill-up and i just put in exactly 6 gallons at the pump. 13.6 mpg. Although i have no idea how i drove 82 miles. Especially when the town i live in is 3.5 miles square. 215/75/15's are HUGE tires compared to the stock 185/70/14s, and the larger tire circumference is going to slow down your odometer. When your odometer says you have gone 82 miles, you've actually gone further, so your true MPG is higher than what you calculated. Link to comment Share on other sites More sharing options...
Markus56 Posted February 26, 2012 Author Share Posted February 26, 2012 aw heck. so what you are saying is, i am an idiot? Link to comment Share on other sites More sharing options...
nipper Posted February 26, 2012 Share Posted February 26, 2012 Ok thats poor, as in you have to work at it poor. Assuming that your idea of acceleration isnt floor the car all the time.. Where do you live How many miles on the car, and how does it run otherwise. When was the last time the brakes were checked (dragging brake), alignment When did this start Any CEL light Link to comment Share on other sites More sharing options...
Red92 Posted February 26, 2012 Share Posted February 26, 2012 aw heck. so what you are saying is, i am an idiot? eh, it's a pretty common mistake. But if you weren't accounting for the differences, then you've probably been speeding everywhere you go too. Link to comment Share on other sites More sharing options...
nipper Posted February 26, 2012 Share Posted February 26, 2012 eh, it's a pretty common mistake. But if you weren't accounting for the differences, then you've probably been speeding everywhere you go too. hehehe the tire size cross posted as i answered. Use a GPS if you have one or the math for the tire conversion then let us know. Link to comment Share on other sites More sharing options...
Red92 Posted February 26, 2012 Share Posted February 26, 2012 Ok thats poor, as in you have to work at it poor. Assuming that your idea of acceleration isnt floor the car all the time.. Where do you live He mentioned before that the drive to work and back was only two miles, the town was only 3.5 miles square, and the nearest population center was 102 miles away but he didn't have a reason to go there. So with those kinds of short short short in-town trips, I would bet that the engine probably never even warms up to an efficient operating temp. Considering the driving conditions, he might even be getting pretty good gas mileage! Link to comment Share on other sites More sharing options...
nipper Posted February 26, 2012 Share Posted February 26, 2012 I can get 12mpg just staying in town with Blu, so, sometimes it is what it is. He needs to find a reason to go into town and back to see what the mileage really is, and to give the car some exercise. With those kind of short trips he should be doing short interval oil changes. Link to comment Share on other sites More sharing options...
Markus56 Posted February 26, 2012 Author Share Posted February 26, 2012 Ok thats poor, as in you have to work at it poor. Assuming that your idea of acceleration isnt floor the car all the time.. Where do you live How many miles on the car, and how does it run otherwise. When was the last time the brakes were checked (dragging brake), alignment When did this start Any CEL light 258xxx miles, i serviced the brakes a year ago, just checked em yesterday, looks good. the car runs like a champ except when you first start it, then it idles at about 500 rpm. no check engine light, and i aligned it myself about 6 months ago. Link to comment Share on other sites More sharing options...
Markus56 Posted February 26, 2012 Author Share Posted February 26, 2012 (edited) He mentioned before that the drive to work and back was only two miles, the town was only 3.5 miles square, and the nearest population center was 102 miles away but he didn't have a reason to go there. So with those kinds of short short short in-town trips, I would bet that the engine probably never even warms up to an efficient operating temp. Considering the driving conditions, he might even be getting pretty good gas mileage! the car does actually warm up to operating temp, thanks to the cardboard i put over the radiator. It would even warm up quickly at -10 degrees before i put in the cardboard. And Nipper, the oil gets changed every 3000, on the dot. I'm wondering if maybe cleaning out the intake might help. And is there a kit out there to rebuild injectors? maybe they have gotten sticky over the years. Edited February 26, 2012 by Markus56 Link to comment Share on other sites More sharing options...
nipper Posted February 26, 2012 Share Posted February 26, 2012 May just be how your driving and how far. 2 miles water is wamed up. Gear lube is no where near warm, neither is engine oil. In the cold i can actually feel the drag of the lubes on the car as opposed to a nice highway run. Link to comment Share on other sites More sharing options...
Markus56 Posted February 26, 2012 Author Share Posted February 26, 2012 (edited) guess i should go to great falls one of these days. maybe i will swing by the subaru dealer there. Also, it's freakin cold here. that probably doesn't help. Edited February 26, 2012 by Markus56 Link to comment Share on other sites More sharing options...
Red92 Posted February 26, 2012 Share Posted February 26, 2012 the car does actually warm up to operating temp, thanks to the cardboard i put over the radiator. It would even warm up quickly at -10 degrees before i put in the cardboard. That's good to hear, but how far are you into your 2-mile drive when it gets there? Even if it does warm up, it might still be spending a considerable amount of time (percentage wise) running below temp... Link to comment Share on other sites More sharing options...
nipper Posted February 26, 2012 Share Posted February 26, 2012 Nothing is going to help as there is nothing wrong with the car. It is the really short drives that kill your gas mileage. If this was an OBD2 car we could prove it with a scan gauge.I have to drive about 7 miles to 19mpg . Doing the mile to my gym if it is bitter cold i get 7mpg, warm about 13. Link to comment Share on other sites More sharing options...
Markus56 Posted February 26, 2012 Author Share Posted February 26, 2012 (edited) In closing, today in class we learned that if i wanted good gas milage, i should have brought my geo metro with me when i moved out here. Edited February 26, 2012 by Markus56 Link to comment Share on other sites More sharing options...
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