Hi There!

My 86 245 w/automic averaged 28 mpg on a 10 hour trip to Chicago last summer.

Erich

Charm's math is correct and your gas mileage is terrible. You should go twice as far on a tank of fuel. It will pay you to correct your problem(s).

Things to check-
1) Is the neighbor kid siphoning gas out of your tank at night?
2) Air filter clean?
3) Fuel injectors clean? (I use Techron)
4) Timing belt correctly installed (cam timing correct).
5) Ignition timing correct and timing advance working.
6) Fuel leaks? May leak only when running.
7) Obstructed exhaust? You should be able to feel the individual bursts of exhaust at the tailpipe opening with your hand when the car is idling.
8) Airbox thermostat closing when warm (not pulling hot air into the airbox).
9) Oxygen sensor in specifications?

If I were you, I'd check on ALL these things, even after you find one or two problems and correct them.

Other things that will cut mileage a little
1) Tires wider than necessary, or under-inflated.
2) Heavy right foot.
3) Excess cargo being hauled around.

Good Luck!
Manolo

There's no meaningful way to measure fuel economy by "km's per tankful" - you have to fill to the brim, note odometer reading, then fill to the brim a few hundred km/mi. later and do the math. It's easy to set up a simple spreadsheet to track these fillups and interesting to see the effect of driving conditions on economy.

My daughter's '83 240 with M46/OD gets 24MPG(US) in mixed city/highway driving, but will turn in about 28MPG with 70-75MPH all-highway use. Those convert to 9.8 and 8.4L/100km, respectively. My son's 81 with M46/OD gives similar numbers.(Take MPG(US) and divide into 235.4 to get L/100km).

As for manual v. automatic, the fuel economy penalty is most significant when the automatic is used in stop/go driving. The later AW boxes feature a torque converter clutch which makes them virtually as efficient at highway speeds as the manuals, even though they will run at a bit higher RPM for a given speed due to their rear axle ratios. My "new" non-turbo 940 automatic returned 30MPG on its maiden highway run, at about 2800RPM. This is 36MPG (Imperial) or 7.8L/100km. At its smog test, the technician said it was burning as cleanly as anything he'd seen in a while, so the engine is in good shape, and tuned correctly.
--
Bob (81-244GL B21F, 83-244DL B23F, 94-940Sedan B230F)

My daughter's '84 with automatic gets a very consistent 22 mpg in what is mostly city driving. The last long freeway trip we took got about 30 mpg. We also have an '86 with 4spd +OD and an '88 with 5-speed. Both of these get about 27 -28 in town and 32-34 on the freeway. Sorry, I'm not too fast on converting to metric.

I live in Calgary and have 2 old Bricks. My 1982 244 with a carb gets about 375-400 km per tank in combined driving and my wife's 1985 245 with fuel injection gets 400-450 km per tank(about 50-55L) with mostly city driving.

I would give your car a good once over to determine if it is operating efficiently. Give it a good tune up and see how she runs.

I have a 1980 DL wagon. On its window sticker when I bought it, it was EPA rated as 18 mpg in town and 22 mpg on the highway. I used to get quite a bit higher than that. Now the car is 23 years old and I get 18 - 20 around town, and higher than 22 on the highway. (Don't drive often or long enough on the highway to give a firm figure here.) Car had a tune up a few months ago, so it should be running optimally. Some others on this board get better mileage than my car does. It cost me $18 to fill up a few days ago, never paid that much before. The attendant told me that it could be a lot worse he had just pumped $70 of gas into a Suburban a couple of days ago!