burtonsnowman Posted October 31, 2006 Share Posted October 31, 2006 1982 GL wagon d/r 4 spd with a quarter of a million miles (257k). I searched. And I searched. I can find nothing wrong with my car. New air filter. New fuel filter. Fresh oil. Fresh oil filter. New plugs. New everything. I drive the speed limit. I don't rev it hard. On my highway commute, I do 62. She runs beautifully and even starts when it's cold outside (9* F this morning). The car is fine! At my last fill-up, I calculated (and re-calculated) 18.42 miles per gallon! What the heck?! Does anyone have ideas as to what might be the problem at hand? (And don't tell me to re-check my math. My math is *perfect*) Link to comment Share on other sites More sharing options...
idosubaru Posted October 31, 2006 Share Posted October 31, 2006 how's the carb? ignition wires, cap, rotor (if it has them, i don't know the EA81's)? does it use any oil? loosing compression? (compression test). Link to comment Share on other sites More sharing options...
scrap487 Posted October 31, 2006 Share Posted October 31, 2006 how do you drive it, ie mostly city or highway? many stops or almost no stops till you turn it off? what rpm range do you usually keep it in? how much stuff do you haul around in your car? what type of tires, check your alignment? etc... do you give it a couple minute for it to warm up before you drive it in cold weather? do you let it cool down for a little bit after driving it before you shut it off? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 31, 2006 Share Posted October 31, 2006 Check your tire pressure to start with. What carb are you running? What size tires are you running? For comparison, my Weber'ed Brat got 28, my Weber'ed wagon gets about 20 with 28" tires. GD Link to comment Share on other sites More sharing options...
scrap487 Posted October 31, 2006 Share Posted October 31, 2006 for some kinds of driving its normal for a subaru to get as low as 20... with my weber if i drive hard I can get it low 14s(mpg not 1/4mile ) but usually with the typical mix of city and highway driving and a fair amount of rough driving i usually get 22-23... had it as high as 29 once on flat highway with nothing in the car. But it does sound like you should be getting better than 18 Link to comment Share on other sites More sharing options...
Sweet82 Posted October 31, 2006 Share Posted October 31, 2006 Your mileage will always go down when the cold weather hits? How long ago was this 18? Was it cold then? Around here they also change the blend of gas for the winter season? Link to comment Share on other sites More sharing options...
burtonsnowman Posted October 31, 2006 Author Share Posted October 31, 2006 Okay. Here's my driving day... I drive 36 miles to school - 30 highway (60-65 MPH), six miles city (35-45 MPH) with a few stops. Then I drive 26 miles to work - 25 miles freeway (60-75 MPH), one mile up a long, windy road (30 MPH) with no stops. Then I drive 42 miles home - mixed freeway (60-75 MPH)/country roads (45-55 MPH). So...A little over 104 miles per day, mostly in a range of 45-70 MPH. My RPMs rarely ever go over 4,200. I checked my tire pressure. All were within 3 PSI. Fixed all of them to perfect. I have the stock Hitachi carb, stock-size all-seasons with 95% tread left, and a Yakima bike rack. I suppose the rack could affect it, but it's been on there since March and the mileage was never this bad then. I guess it must be time to check out the carb. It's running fine, but obviously something's wrong. Any ideas? I have never gotten above 22 MPG in it (owned it since March), but this 18 is exceptionally low - especially since I drive almost all highway. And yeah...I let it warm up for five to ten minutes every morning. ? Link to comment Share on other sites More sharing options...
NorthWet Posted October 31, 2006 Share Posted October 31, 2006 Does your 82 have a feedback carb? (Does it have an O2 sensor and an ECU?) If so, O2 or feedback ciruitry (electrical/vaccum) may have a problem. Link to comment Share on other sites More sharing options...
cubastreet Posted October 31, 2006 Share Posted October 31, 2006 Also check the choke is working correctly. If it's auto choke, make sure it's fully open when the engine's warmed up. Link to comment Share on other sites More sharing options...
kayakertom Posted October 31, 2006 Share Posted October 31, 2006 Check for brake drag problems by jacking up each wheel and see how easily they spin. Also on a nice flat paved section of road get up to 25mph with the windows rolled down, put in neutral, coast to a stop and listen/feel for anything dragging. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 31, 2006 Share Posted October 31, 2006 Yeah - as mentioned above the "feedback" systems tend to run rich when they aren't functioning properly. One cheap way to start diagnosing things would be to get an Air/Fuel ratio meter (or build one!) and monitor that while you are driving. You will learn SOOOO much about how the engine uses fuel and where you need to make corrections. It helps tremendously with getting your mileage figures up as it comes in handy not only for tuning, but also to adjust your driving patterns to get a nice lean cruise mixture. It's a cool project, and a great learning experience. AFR's can run as low as 12.5:1 at full peak HP, and as lean as 17:1 at cruise on the freeway. I would also consider just tossing the Hitachi. Sadly it has a lot of problems that are not easily corrected. A rebuild may help some, but probably won't get you into the 28-30 mpg range that a simple Weber swap would. That said, I have had non-feedback Hitachi's that would run around 28 mpg as well. I had a feedback that would get around 28 mpg in my 2WD wagon which I *thought* was good. I swapped to the weber and that car got very close to 33 mpg on the freeway. I would say that you should be getting around 26 with that roof rack. Those things really are a drag. GD Link to comment Share on other sites More sharing options...
89thorn Posted December 1, 2006 Share Posted December 1, 2006 My 89 wagon noticed a drop in 2 miles to the gallon from 32. All because of wheel bearings starting to go out. The rumbling noise is first symptom. I just ridem till i get the slight shakes. The junk of my life is a chevy s10 it droped to 12 mpg i checked and replaced and checked again. in the end it was a pin hole leek from the bottom of the gas tank. SLOW BUT LEATHAL. So if you ain't allready checked for fuel leaks might be a good idea. IF it aint the carb or bearings.:-\ Link to comment Share on other sites More sharing options...
zyewdall Posted December 1, 2006 Share Posted December 1, 2006 After a long highway run, stop and feel all of the wheels (hubs and brake parts). If any of them are warm, either a wheel bearning might be going, or brake sticking. My '89 wagon just recently went from always getting 28 to 30, to below 25 -- and the front rotors are always warm now. And on the last tank I only got 20 -- from a day or two of slogging through 6" to 15" deep snow in low range. My old '82 wagon used to get 27+ most the time, was dropping to 23ish from a completely worn out carbureator when I got rid of it. Mostly city and mountain driving. Link to comment Share on other sites More sharing options...
Frank B Posted December 5, 2006 Share Posted December 5, 2006 Check all the before mentioned things, then rebuild/clean your carb. There isn't much rebuilding to it really. Just a new accelerator pump, new needle and seat, and gaskets. But cleaning it is the most important part. Get some good cleaner, not the $1.00 stuff. Follow the sheet in the rebuild kit to set the float and choke linkages. If you feel up to it, drive out the idle mixture screw block off pin on the front of the carb while it's out. After the rebuild and re-install, let the car get up to temp, check/adjust the ignition timing, set idle speed to around 800 rpm and turn the screw in untill it starts to stall. back it out untill it runs smooth again. Re-adjust idle speed if needed, then adjust the mixture screw again the same way, then idle again if needed. My worn out Hitachi carbed 89 hatch gets me 30MPG highway, 25 before the rebuild. Link to comment Share on other sites More sharing options...
nipper Posted December 5, 2006 Share Posted December 5, 2006 Do two checks, one is simple. Get a vacume gauge and hook it up. Give us the readings, as we can tell the health of the enigine by what the needle is doing and what it is reading. Next you may want to do a compression test to make sure mechanically the engine is not feeling its age. Carberator is the most likely suspect when everything else is exhausted, but it would be to get status on the engine health. nipper Link to comment Share on other sites More sharing options...
subiemech85 Posted December 6, 2006 Share Posted December 6, 2006 it's a subaru, get over it and consider yourself lucky you get that much! Link to comment Share on other sites More sharing options...
nipper Posted December 6, 2006 Share Posted December 6, 2006 it's a subaru, get over it and consider yourself lucky you get that much! er um, on my 1988 GL i got 24 around town and 34 on the highway, he is a bit low. If you search the gas mileage topics people get higher then that with the 1.8L unless hes got an automatic. nipper Link to comment Share on other sites More sharing options...
burtonsnowman Posted December 6, 2006 Author Share Posted December 6, 2006 it's a subaru, get over it and consider yourself lucky you get that much!Wow...thanks for that awesome advice, sir... So, I kept driving and I'm averaging (over the course of 7 fill-ups) somewhere in the 19.2 range. ignition wires, cap, rotor (if it has them, i don't know the EA81's)? Monday (payday) I'm going to replace these parts. does it use any oil? Hee hee, good one. A Subaru with 258k miles on it...YES IT USES OIL! ...Burns oil like a motha' trucka'... Link to comment Share on other sites More sharing options...
nipper Posted December 6, 2006 Share Posted December 6, 2006 Wow...thanks for that awesome advice, sir... So, I kept driving and I'm averaging (over the course of 7 fill-ups) somewhere in the 19.2 range. Monday (payday) I'm going to replace these parts. Hee hee, good one. A Subaru with 258k miles on it... YES IT USES OIL! ...Burns oil like a motha' trucka'... and that answers my question on the condition of the engine, then just be happy it runs. nipper Link to comment Share on other sites More sharing options...
burtonsnowman Posted December 6, 2006 Author Share Posted December 6, 2006 and that answers my question on the condition of the engine, then just be happy it runs. nipper Okay...maybe my statement was an exaggeration. It burns one quart per 500 miles. Link to comment Share on other sites More sharing options...
nipper Posted December 6, 2006 Share Posted December 6, 2006 Okay...maybe my statement was an exaggeration. It burns one quart per 500 miles. heheh thats still alot nipper Link to comment Share on other sites More sharing options...
bgd73 Posted December 6, 2006 Share Posted December 6, 2006 ...... I guess it must be time to check out the carb. It's running fine, but obviously something's wrong. Any ideas? I have never gotten above 22 MPG in it (owned it since March), but this 18 is exceptionally low - especially since I drive almost all highway. And yeah...I let it warm up for five to ten minutes every morning. ? It is Carb or fuel pump, if all the tune up regulars are good (cap, rotor, wires plugs, filters,timing, belts, etc). I adjusted a float bowl level in my 87 hitachi becuase it was a few mm low from oem (1/8th inch?). I could even spot a fuel level line from the years to get an exact measurement of how wrong it was. Fuel mileage nearly doubled into the mid 30s as average (as should be expected from 250cfm, a super tight air plenum and a very small 1781cc). I was further astonished after changing the fuel pump- mpg was 40's on the highway and even touching off 50. Even with the oem fuel pump going psych-owed in the cold, the carb set correctly, and even slight over fill the bowl (very slight only if it is old and original metal float) was incredible results. I also found a loose part near the top of carb after getting into the top layers. That too helped out sloppy mileage after tightening. That part has a name and mentioned here at usmb (as a source of carb backfire when loose), I don't know what it is or what it does, but it did need to be tightened with a philips screwdriver, and helped for a strong thumpier idle in all weather. The carb you have is all there and functioning, it is just adjustments. Another note, as with all carbs, old floats start to sink even if they are adjusted correctly, its like they gain weight and defy your adjustment after back together again. Napa I have found has a carbon version float for the soob hitachis, I bet it is quite responsive and it is cheaply priced. That is where I am headed for my 20 year old hitachi, may not even get a kit, just the light tight float. Link to comment Share on other sites More sharing options...
suburpy Posted December 6, 2006 Share Posted December 6, 2006 Hey I recently had bad mileage was getting 12-13l/100km rather than the usual 9-10l/100km. Had my dizzy cleaned, rebushed and the vauum advance checked. Turns out mechanical advance was stuck, not moving smoothly. already had the new plugs, filters, air cleaner, etc runs great now at 9l/100km. Also if rebuiding carby (like I will do soon) either go the weber or check the throttle shaft free play (you cna get it rebushed for about $20, from any carby rebuild place). Not just cleaning involved in a rebuild. Link to comment Share on other sites More sharing options...
subiemech85 Posted December 7, 2006 Share Posted December 7, 2006 are you burning or losing oil? used to drive a ea81 that got 1qt oil added for every tank of fuel, until the valve cover gaskets were changed, and the oil pan tightened ea71 just got 18.6 Wo friggin HO Link to comment Share on other sites More sharing options...
heartless Posted December 7, 2006 Share Posted December 7, 2006 after reading all the replies, only one person even mentioned an obvious possibility - fuel leak somewhere... would thoroughly inspect all fuel lines, pump, and tank for even a tiny leak - as it can/will affect your fuel mileage. look for any damp/wet spots when weather has been dry... had to completely replace a metal line on my wagon with a rubber one as the metal line had rusted out in a couple of spots. have an 88 coupe that had a leak at the fuel pump (common in the snowbelt for the style pump this car has) swapped fuel pump out, fuel mileage has improved dramatically Winter weather will cut fuel milage - warm up time eats it up. my 89 EA82 wagon will run about 34mpg in the summer, but drop to 28-30mpg in the winter - that being said, you should still be seeing better than 18mpg, even on a carbed EA81 good luck Link to comment Share on other sites More sharing options...
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