goobaroo Posted February 2, 2007 Share Posted February 2, 2007 ok 14-15 mpg on an '84 GL wagon w/EA81 is absolutely unacceptable! timing: 8deg btdc no AC compressor new oil less then 150 miles new oil filter less then 150 miles new gear oil less the 150 miles perfect tire pressure checked weekly on 225/70R14 new fuel filter/fuel vapor seperator fuel pump runs great EGR not hooked up, vacum hose capped charcoal canister removed and all hoses capped carb looks great, really clean, jets r clear and free flowing, accel pump works great too new disty cap and rotor new plugs NGK's New plug wires 8mm accel's new accel superstock coil shifting at 3500rpms mostly cruising at 55mph so i should be getting optimum milage one bad wheel bearing but i don think it would make that much of a difference so after all this im really really stumped. any suggestions are welcome. i would like to get around 35-40mpg as ive heard from others....im blowing through cash on gas i fill up almost 3 times a week! Quote Link to comment Share on other sites More sharing options...
GoldDiggerRoo Posted February 2, 2007 Share Posted February 2, 2007 Is it an auto? every auto wagon I've had would struggle to get past 18mpg Quote Link to comment Share on other sites More sharing options...
75subie Posted February 2, 2007 Share Posted February 2, 2007 whoever told you they get 35-40 is full of crap.. maybe in a fwd 5sp and driving like granny. the average ea81 will usually do 25-28. yours sounds like a tuning problem for sure. i`m sure GD will chime in here with some suggestions Quote Link to comment Share on other sites More sharing options...
[HTi]Savage Posted February 2, 2007 Share Posted February 2, 2007 What was the milege before the 14's. And are ur plugs gaped right. Also make sure that ur brakes arent dragging. how long has it been running this way? Quote Link to comment Share on other sites More sharing options...
[HTi]Savage Posted February 2, 2007 Share Posted February 2, 2007 Make sure u dont have any air/vacum leaks some are hard to find. Quote Link to comment Share on other sites More sharing options...
Frank B Posted February 2, 2007 Share Posted February 2, 2007 Have you rebuilt the carb yet? Reconnect the EGR and clean the passages. reconnect your evap canister and any other emmisions stuff too and see what happens. I get 29.5 to 32 mpg in my 89 ea81 hatch 4wd 4-speed. I drive it 96 miles a day and 90% is interstate at 70+ mph. The most mpg increase I got was after I rebuilt the carb. The next highest was after I cleaned the plugged PCV valve and EGR. Quote Link to comment Share on other sites More sharing options...
goobaroo Posted February 2, 2007 Author Share Posted February 2, 2007 its been running like this since i got it back in september, just kinda ignored it. the milage was the same before the bigger tires probs 2-3mpg better, i expected it to drop a little. yeah i'll have to check the plugs and the brakes. ive put new pads on since i got it but that was during the first week of driving it. i also noticed there really isnt anything to pull the pads away from the rotors when u let off the brakes, like a return spring so maybe they are rubbing. oh and its a 4spd manual with d/r i should also mention, i put all that new stuff on because the car hadnt been run in about 6 years when i got it....but the sucker fired right up first time! Quote Link to comment Share on other sites More sharing options...
goobaroo Posted February 2, 2007 Author Share Posted February 2, 2007 ok i'l check the EGR, cant replace the canister as i threw it out...oops. and i'll have a look at the pcv valve too....maybe a carb rebuild is in order...but it looks so clean! Quote Link to comment Share on other sites More sharing options...
Hodaka Rider Posted February 3, 2007 Share Posted February 3, 2007 Has your disty ever been rebuilt? I gained some mileage and drivability after rebuilding mine. Do you have the feedback carb? Any codes? How about the O2 sensor? Also, there is nothing weird about the way the brakes work. Have you done brakes on other cars? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 3, 2007 Share Posted February 3, 2007 The 4 speed gearing, and the big tires are going to kill the mileage. Granted it should be a *bit* better than 15, but not a lot. My lifted wagon started as a 2WD 5 speed. With the Weber it got 33 mpg. Once lifted, with 215/75Rr15's, and the 82 4 speed (same engine, same carb, no changes at all), my mileage is 20 - 22 mpg. 35 to 40 is laughable - whoever told you that was on crack. The Justy was barely that high in 2WD form. The EPA rating for a stock EA81 (non-turbo) was 28 to 30 mpg. And mostly you'll see 28 or 29 on a stock 4WD in my experience. GD Quote Link to comment Share on other sites More sharing options...
86BRATMAN Posted February 3, 2007 Share Posted February 3, 2007 whoever told you they get 35-40 is full of crap.. maybe in a fwd 5sp and driving like granny. the average ea81 will usually do 25-28. yours sounds like a tuning problem for sure. i`m sure GD will chime in here with some suggestions out here in the mountains i got in the upper 30's mpg with an 84 4spd d/r wagon, not driving like a granny, car had p/s and ac, kept in perfect tune, it is possible, just not probable Quote Link to comment Share on other sites More sharing options...
4x4_Welder Posted February 3, 2007 Share Posted February 3, 2007 Are you calculating mpg per the odometer, or actual mileage travelled per maps/ map services? Quote Link to comment Share on other sites More sharing options...
baccaruda Posted February 3, 2007 Share Posted February 3, 2007 it's been mentioned before that crusty wheel bearings can add a LOT of rolling resistance.. just another thing to check. next time your gas tank gets low, pour in a bottle of Seafoam and top it off with a gallon of gas. Drive around for a while and let the higher concentration of SF give your carb a good ol' Quote Link to comment Share on other sites More sharing options...
goobaroo Posted February 3, 2007 Author Share Posted February 3, 2007 im using my trip odometer because my gas gauge doesnt work, so everytime i fill up i calculate the milage and then reset it. ive run seafoam throught the gas, and some in the oil for just a day before i changed it. then i also ran another whole can through the engine via the carb at high rpm. i guess im just going to have to check the wheel bearing, its the rear so its a PITA to replace. also this isnt a feedback so no codes to check. does anyone know the actual capacity of these tanks, i know my original manual and the brochure from '84 both say 14.5gal but i emptied the tank completely (till the car stalled and wouldnt start) then refilled and it was slightly less then 12 gallons. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 3, 2007 Share Posted February 3, 2007 im using my trip odometer because my gas gauge doesnt work. That's your problem. Because of the tire differences, your odometer is running slower than normal so you are showing fewer miles than you have actually driven. You can't calculate your mileage on this - it could easily be as much as 50 miles off or more. Just for reference, with 28" tires, 46 Mph on the guage is actually 55 Mph on the road. At a constant speed, every hour that you drive shows 9 miles less than you actually covered. HOWEVER - you cannot calculate backwards from the odometer to actual traveled miles. This is because the rate of change is a percentage of the original. IE: your guage shows 0 MPH when you are going 0 MPH, but shows 65 when you are doing 80 (or whatever). The difference between the odometer and the real traveled difference is not a linear function so you can't map it backwards without considering the derivitive (rate of change) of your speed. That's a calculus problem, but in real life it's an impossible one because you make too many changes to your speed while driving to be able to set any sort of function to the data...... you *could* do it with a Polynomial (Integrated, it would give you the total distance - see here if interested!! http://en.wikipedia.org/wiki/Polynomial_interpolation ), but it's too much work, and you don't have enough data points. Plus every single trip would result in a different function graph..... wow that would be too much work....... cruel project for some poor calc student tho. Maybe visit the local campus and see if a prof. wants to try it..... hehehe. Basically just use mile markers or mapquest or something to calculate your mileage. Or GPS if you have it. Tank capacity of a standard EA81 4WD wagon tank is 14.5 gallons, but you'll be lucky most times to get 13.5 to 14 in the tank. That last 1/2 gallon is pretty much unusable. GD Quote Link to comment Share on other sites More sharing options...
4x4_Welder Posted February 3, 2007 Share Posted February 3, 2007 Your odometer shows less miles than you actually travel, due to the larger diameter tires. To find your actual mileage, either map out distance, or calculate how much your is off by tire diameter. Quote Link to comment Share on other sites More sharing options...
goobaroo Posted February 3, 2007 Author Share Posted February 3, 2007 damn why didnt i think of that, yeah wow blew right by me. thanks guys! im still gonna fix the other stuff at least i know that'll help a little. and as soon as this cold weather ends im putting my regular tires and 13in wagon wheels back on! as for calculating the milage from now on...forget it...if my first year of college as a mechanical engineer taught me anything....its that calculus is a bigger PITA then fixing anything on my car! Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 3, 2007 Share Posted February 3, 2007 as for calculating the milage from now on...forget it...if my first year of college as a mechanical engineer taught me anything....its that calculus is a bigger PITA then fixing anything on my car! Yeah - but at least you know HOW to do IF you wanted to. Sad to think that I went to what was considered at the time to be one of the top 100 HS's in the country, and yet my math teacher was unable to tell me how my handlheld calculator can figure the SIN of an arbitrary angle without measureing the lengths of the sides of the triangle.... come to find out later when I took Calc that it's a Taylor Polynomial..... he really should have known that to be teaching HS math IMO. Whatever. There's an easy way to fix your speedo - there's actually speedometer shops that can splice in a reduction drive unit for about $100 or so. The gears are changeable for different tire sizes, etc. They do it all the time for lifted trucks. GD Quote Link to comment Share on other sites More sharing options...
casioqv Posted February 3, 2007 Share Posted February 3, 2007 The difference between the odometer and the real traveled difference is not a linear function so you can't map it backwards without considering the derivitive (rate of change) of your speed. That's a calculus problem, but in real life it's an impossible one because you make too many changes to your speed while driving to be able to set any sort of function to the data. Why do you say the distance is not linear? The rolling circumference of the tire is a fixed ratio relative to the factory tire rolling circumference. The odometer is geared at the factory to record a specific number of tire rotations as a mile. As the vehicle moves one tire circumference per axle rotation, you just multiply the mileage the odometer reads by the ratio of the tire circumferences and you have the actual distance travelled. There is no calculus necessary. As you said, the odometer can be fixed by adding a reduction gear box to the odometer cable. A reduction gear box can only change the speed by a linear factor. Also, polynomial interpolation (fitting a curve to a set of data points) is not calculus, it's statistics. I use a cheap $75 GPS to calculate my fuel economy, as it will also record my average speed so I can calculate how that affects the fuel economy. he really should have known that to be teaching HS math IMO. Whatever. It's pretty sad, but you don't actually need a degree in a subject to teach it. Often the teachers level of proficiency in the subject in high school, is just what they learned in high school and nothing more. A good portion of the science taught in high school is just plain incorrect. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 3, 2007 Share Posted February 3, 2007 Why do you say the distance is not linear? The rolling circumference of the tire is a fixed ratio relative to the factory tire rolling circumference. The odometer is geared at the factory to record a specific number of tire rotations as a mile. As the vehicle moves one tire circumference per axle rotation, you just multiply the mileage the odometer reads by the ratio of the tire circumferences and you have the actual distance travelled. There is no calculus necessary. As you said, the odometer can be fixed by adding a reduction gear box to the odometer cable. A reduction gear box can only change the speed by a linear factor. Hhhmmm - yes. I thought about it too hard :-p. You are correct sir - one need only multiply by the percentage difference in tire circumference. I tried it out to verify..... deceptive when you think about it in *just* the wrong way. lol. Although, for the record - my method ALSO works. It's just totally uneccesary, and somewhat less accurate. Also, polynomial interpolation (fitting a curve to a set of data points) is not calculus, it's statistics. Yes - I was refering to the Integral of said curve. It helps to have the function to take the Integral of though. And polynomials have applications beyond *just* statistics. I linked to that article as it was most appropriate for my totally invalid reasoning on the non-linearity of the relation :-\. My bad. Dangit! Calc. can be fun too. Oh well - there's other applications. It's pretty sad, but you don't actually need a degree in a subject to teach it. Often the teachers level of proficiency in the subject in high school, is just what they learned in high school and nothing more. A good portion of the science taught in high school is just plain incorrect. Yeah - well supposedly our school was well funded and we were always told we had the *best* money could buy. Sadly that really doesn't seem the case on reflection years later..... GD Quote Link to comment Share on other sites More sharing options...
baccaruda Posted February 3, 2007 Share Posted February 3, 2007 I would get myself a set of stockish "commuting" wheels and tires and see how the mileage went from there. Quote Link to comment Share on other sites More sharing options...
jacobs Posted February 3, 2007 Share Posted February 3, 2007 35 to 40 is laughable - whoever told you that was on crack. GD I'll bet you $1000 I do. Just come here and I'll show you anytime....AND I'VE NEVER DONE ANY DRUGS!!!!!!!!!!!!!!!!!!!!!!!! Don't forget to bring your money.....A FOOL AND HIS MONEY ARE SOON PARTED. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 3, 2007 Share Posted February 3, 2007 I'll bet you $1000 I do. Just come here and I'll show you anytime....AND I'VE NEVER DONE ANY DRUGS!!!!!!!!!!!!!!!!!!!!!!!! If you can afford to pay me $1000 to come see you not get 40 mpg on your EA82, then you can certainly afford to spend the few $ it would take to get real accurate data, post it here, and allow us to show you where you have most certainly gone wrong with your calculations. Sorry, but simply proving it to *me* (which you can't) wouldn't be enough. You have to prove it to everyone here. You continue to proclaim this from on-high, and yet have failed to provide your methods, testing procedures, and calculations to backup your claim. Till you provide a complete white paper so the data can be repeated by others, it's just hot air. GD Quote Link to comment Share on other sites More sharing options...
jacobs Posted February 3, 2007 Share Posted February 3, 2007 If you can afford to pay me $1000 to come see you not get 40 mpg on your EA82, then you can certainly afford to spend the few $ it would take to get real accurate data, post it here, and allow us to show you where you have most certainly gone wrong with your calculations. Sorry, but simply proving it to *me* (which you can't) wouldn't be enough. You have to prove it to everyone here. You continue to proclaim this from on-high, and yet have failed to provide your methods, testing procedures, and calculations to backup your claim. Till you provide a complete white paper so the data can be repeated by others, it's just hot air. GD I've said I get 36 to 41 mpg. I can make up all kinds of stories and post them here. There is only one way to prove it...to SHOW YOU YOU JERK. PUT YOUR MONEY WHERE YOUR MOUTH IS!!!! Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 3, 2007 Share Posted February 3, 2007 I've said I get 36 to 41 mpg. I can make up all kinds of stories and post them here. There is only one way to prove it...to SHOW YOU YOU JERK. PUT YOUR MONEY WHERE YOUR MOUTH IS!!!! Clearly you don't understand. Emperical evidence is not proof. We require hard data. You can jump up and down and claim the earth is flat all you want - I nor anyone else here will believe your claims without reproduceable data. That's how science works. Sorry. If I'm a jerk for saying what we're all thinking.... well so be it then. We would all love to get this mythical unicorn mileage you have - so help us out. Be all you can be. If it's true maybe CNN.... Leno - who knows. Sky's the limit man. GD Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.