Gas Mileage - Almost As Popular As Wheel Size....

Post by **ARCHINSTL** » Thu Dec 29, 2005 1:48 pm

Ok - I'm wondering here.........
I realize that I have a lot of fiddling still to do, as the carb is a new/reman and I'm feeling my way around the idle mixture screw adjustment - and the motor has 171K on it - and it likes to be thoroughly warm so it won't die at stops (thus wasting gas in the process) - but my last tank averaged just 22 MPG, with maybe 100 miles of 60 MPH +/- of highway driving. I got 33 MPG (55 MPH MAX-45 MPH on gentle hills) driving up here from TN when I got the car with so many issues/missing parts/broken parts/wrongly routed vac lines that I am now amazed it ran at all.
Further tuning and warmer weather should help, I realize.
However, my (then-new) '83 got much better mileage, as well as many lower RPMs at 60 MPH, with less noise (obviously) as well. While cutting the '86 some slack for its age, I wonder if the mileage of the two years cannot really be compared because of the different gearing ratios? The '86 is sure a buzzbox compared to the '83 - at least as far as my memory goes - the one daughter who has thus far ridden in it has also commented on the noise difference.
Any thoughts on the mileage, vis-a-vis the gearing?
Tom M.

Typrus · Post by **Typrus** » Thu Dec 29, 2005 6:40 pm

86- Just off of memory- Highest ever seen was 37mpg, lowest ever was 21mpg
84- Highest- 29mpg, lowest- 12mpg. 2000+ mile average- (crap, wheres my calculator??? It has the bloody log on it.....) Ok. Found calc... Average as of 2237.8 miles since logging (I round what I can to the 2nd decimal) I've used 100.548 Gallons to equate to 22.256 mpg.

I never tweaked the carb on the 86.

I'm a special situation. The engine I'm running in my 84.... Is out of my 86! So, the emissions equipment removed aside, I should be getting similar results? Well, It's hard to tell. The crash seemed to dork up my carb, and the engine BARELY ran after the swap. In fact, I got stranded many times. And I have no cell phone, so that was a fun time.

I finally had the carb rebuilt. That helped a very large deal, as the best I saw pre-rebuild was 17mpg but averaged about 14. I still did not see the powerband, economy, and drivability I experienced in my 86. I was almost tempted to swap the tranny/drivetrain from the 86 over to see the difference, but figured that was way to much trouble just for an experiment.
I just recently changed air filters (to no improvement, shockingly) and the PCV valve... Along with a new battery and leads, as my old battery was an acid-gooing mess. The air filter was about 500 miles ago, while I have only driven .25 miles on my new battery and PCV valve... No difference thus far. I'm going to change the oil to see what happens. I'll be buying high quality tranny oil and rear diff fluid ASAP to see what happens, but most importantly I NEED, without question, new bushings, springs, struts, and shocks. No idea if that'll help mileage through wheel control.... Or let me ruin mileage through harder cornering lol.
That brings me to a thought; The highest mileages I saw on either vehicle was attained through a 2-tank period of agonizingly boring driving for good economy. Well.... Actually, it started in the 86 with about a 10 tank period of finding out what was TOO gentle (I saw 23mpg, worse than my average of 25 going too gentle)and what was a little too hard.

Dang.. Sorry to get sidetracked.
Anyway, sound difference? I really did not see much of one. Initially, I heard more tranny noise from the 84 than the 86, but it turned out to have tar-colored gunk for tranny fluid.

Personal opinion? There are subtle differences between the years, and it just depends on both what particular individual car you get, and which generation/year you STARTED with.

Looking at the carpet on either one, it is the same thickness and, apparently, material. There is no extra padding on one or the other I've seen that would attribute to better road sound characteristics.

I can say that I had a lot more fun driving my 86, but look where that got me. I think overall though, I've had more fun with the 84, just out of how often it keeps me thinking.

hberdan · Post by **hberdan** » Sat Dec 31, 2005 5:28 pm

I live in Colorado. Lots of mountain driving right now, lots of skiing!
My gas mileage suffers because of cold starts and long warmups, and running 4 snow tires (not studded). Also have a less than streamlined old style Barrecrafter ski rack mounted all winter.
The engine has a factory-installed block heater, which helps warm-ups at home, but leaving a ski area at dark in 0 degree (F) weather requires long idles. Not to mention all the high altitude up and downs on the road. From my house to my "office" is a 4200' climb.
My car, an 87 Deluxe 4x4, gets somewhere between 25-28 mpg in the winter.
In the summer, with all seasons on, and no ski rack, and of course not as many cold weather warm-ups, I get somewhere around 29-31 mpg.
Not bad for a 19 year old car that has 246,000 miles on it.
I know some other Colorado Tercel wagon owners like to go rreally fffast, but I don't run it too fast on the highway, keep it at the speed limit most of the time. Don't want to waste the gas, don't need the tickets and the $$ fines.

Lollypop · Post by **Lollypop** » Sat Dec 31, 2005 8:46 pm

Well I guess I'll jump in on this one.

I actually have two Turtles: 1987 2WD - Red, I have had it close to a year
1985 4WD SR5 - Purple with dark purple flames
ewwwwwwwwwwwwwww!!!!

On the 2WD I get around 28 in town/32 highway......the 4WD gets around SHITTY seriously it gets about 12 in time or atleast on this first tank (just got it) My carb is running real rich, it will flood itself out at red lights if I dont watch it. BUUUUt I'm saving my money right now for my new Redline Weber kit ($412.00) I'll have it soon and wont have this prob. I may rebuild the old one for now.

-----Justin-----

Typrus · Post by **Typrus** » Sat Dec 31, 2005 9:39 pm

I wish I got that lol hberdan...... Well, if you see a Silver Tercel whipping by you in the fast lane going 80+, it's probably me. I suppose 22mpg going 80+ for 200 miles is an achievement.
I'm altering my driving style, perhaps temporarily, to try and keep RPM's under 2500 as much as humanly possible. I've been honked at once so far, but it's going over alright thus far. That and I got 25 mpg with about 80% below 2500RPM's, the other 20% hitting 4 grand or so with my 400lb friend riding shotgun.
I saw a van go through town advertising these things called Air Tabs.... Looked fascinating... http://www.airtabs.com I think.

hberdan · Post by **hberdan** » Sat Jan 07, 2006 4:44 pm

You'll probably never get a ticket, at least one that sticks, there is no judge that would really believe that an old Tercel wagon would go that fast!

takza · Post by **takza** » Sun Jan 08, 2006 6:20 am

Lollypop wrote:My carb is running real rich, it will flood itself out at red lights if I dont watch it. BUUUUt I'm saving my money right now for my new Redline Weber kit ($412.00) I'll have it soon and wont have this prob. I may rebuild the old one for now.

-----Justin-----

If you take the air cleaner off...you can get a look at the glass window in front...probably have a messed up float or valve? Level too high?

Mosquito · Post by **Mosquito** » Sun Jan 08, 2006 8:19 pm

My first two tankfuls after getting the car in November, I was gtting around 16! But it was really cold, I was making short trips, and it needed a tuneup, bad. I've done the tuneup (except for timing and idle/mixture!!!) and already it's up to 22 mpg. For some unknown reason, the p.o. had plugs that were gapped waaaaay large, like well over twice the gap recommended. And the PCV valve was toast. And the carb was gunky.

I figure getting the timing back in line (I think it's too far advanced) and stopping it from running rich ought to squeeze out some more mpgs.

Ogedei · Post by **Ogedei** » Wed Feb 08, 2006 6:02 pm

I thought I would weigh in. I live in a mountainous environment. I have a 1500 foot change in altitude over a 25 (one way) mile trek (lots of up and down). IN 4th at 3k I can manage 55 uphill and 5th 3k I can average 65-80 downhill. Most of my miles are high speed +50. I am averaging 27 mpg. I am about to embark on a quest to squeeze both power and mpg out of my terc. I know that many times they are mutually exclusive but if I can increase my power I should be able to maintain speed without adding pedal.

My first task will be to take out the plugs, gap, side gap and point them to the exhaust port per another post here about alignment. I will advise what these changes might accomplish. When the plugs are out I was going to do a dry compresion test as well.

takza · Post by **takza** » Wed Feb 08, 2006 6:34 pm

While you're messing with plugs...you might want to try this...?

http://fueleconomytips.com/index.php?op ... 1&Itemid=2

Got mine indexed...wasn't easy at all though...also closed the gap some as per LaPointe...haven't been able to test it.

This is easy to setup....

http://fueleconomytips.com/index.php?op ... 9&Itemid=2

JOE · Post by **JOE** » Wed Feb 08, 2006 7:17 pm

I know since I replaced my tranny with one out of an 83 wagon I now get better mileage, but do lack the torque, going up the skihill, that I had with my 85 tranny. I think the ratios in the 85 are 410, while the 83 has 373.
Anyway, figured out there were different ratios the first time I tired 4WD.
Just about pulled the car apart. Had to change the rear diff to match the ratio.