215 miles on an SC tank! What gives?

[yelcab1]

I have been getting around 215 miles on 16 gallons from my SC. With the gas prices at they are lately, I have got to make it better. So far, the car has new plugs, new cap, new rotors, new plug wires, and passes smog.

All exhaust is stock, with O2 still plugged in.

[GrindingGears]

Shift up sooner?

[Superman]

http://forums.pelicanparts.com/showthread.php?threadid=144601&highlight=Gilligan

[johnsjmc]

Advance the timing 3 to5 degrees. Verify the CO readings are not too rich . Consider a new O2 sensor as they get lazy with age and catalysts get partly plugged. And check for things like dragging brakes and excessive toe in. Dragging brakes is common on cars which are allowed to sit for periods of time.I assume you have no leaks. Lastly remember the SC ,s don,t get nearly as good mileage as the Carrera,s do

[Pete000]

I would run a couple of tanks with Chevron Techron fuel injector cleaner. I have noticed that on a high way trip my car got noticable increase in fuel economy after burning a tank full. Itseems to work better if you can mix it in on an empty tank then fill it up and run the tank through all in one session such as if you are going on a trip. I run a bottle through about every 10th tank. My old Vanagon ran rough and after doing this as well as basic tune up stuff it has been getting beter fuel milage and runs much smoother. Also when was the last time you changed the fuel filter?

[na2ub]

That's what I get. I think I have too much toe-in in the front, though.

[HarryD]

Originally posted by Superman
http://forums.pelicanparts.com/showthread.php?threadid=144601&highlight=Gilligan

Super,

I knew you would find a way to revive this thread!

[goliver]

I have a '79 and am getting the same mileage as you. 13ish in my mostly city commute. It sucks as my '87 928S4 with two extra pistons and 2 more liters gets 14 during the same thrash. I posted on this board and the Rennlist and most thought my car is running rich. In my queary to the lists, on average an SC driven moderately to hard should see 16+ in town. Get you mixture set and maybe a new o2 sensor.

Geoff

[singpilot]

I commute almost weekly between Las Vegas and Los Angeles. Mileage around town can be 12-ish if you are in it all the time. I am.

I can see 320 miles on 16-ish gallons on the road. Minimum 80MPH, sea level to 4700' passes across the desert. Averages 17 to 21 MPG. Best ever was 27 MPg with a 40 knot tailwind. Worst ever was 15 with the same headwind.

Techron every third month or so, usually right before an oil change. Sounds like you need an Italian tuneup.

[Superman]

My mileage got almost down to ten mpg, until Gilligan confessed to moving the crab stake. In reality, 17-22

[nostatic]

I'm getting around 13mpg, but I also think that my gas cap isn't doing a very tight seal anymore (or since the tank was replaced).

Gilligan was also hoofing ethyl, but that is another story...

[pbs911]

Sounds about right.

Gilligan was also hoofing ethyl, but that is another story...

I always heard he was doing Mary Anne......

[goliver]

I used to own an '80 targa and I don't know if it is because that is the first year for the o2 sensor or what but it got 17-20 in town and high 20s low 30s on the highway which seems fairly consistent with MY80-83 SCs. All the responses I got from owners of '78-79 cars were similar 12-14 city, 19-21 highway. Some attributed it to diffent intake runners on these MYs. I don't know how much difference that would make. Do think a vavle adjustment and a complete tuneup is in order to get at least all the old girl is capable of. After hearing my car wasn't hugely out of line I just figured what the hell i'm driving it like its a rental (with proper maintenance of course) and have fun.

Cheers,

Geoff

[no substitute]

You couldn't find a photo of her in the short shorts then?

[Graham Archer]

Another data point for you: 17-19mpg city, 25-27mpg highway (@75-80mph). O2 sensor connected.

[trj911]

I get in the 13-16 mpg range so yours doesn't sound too far off. I got a bit better in my '73 but not much.

Have you tried driving down hill all the time?

[greglepore]

Check your odo against a measured mile. I'm serious.

[cab83_750]

Originally posted by Graham Archer
....... 25-27mpg highway (@75-80mph).

I get over 400+miles on a tankful (without the red light going off, and with my o2 sensor disconnected).

[geof33]

Now that I'm lighter... I average 21 or so around town, if I'm not in it constantly, close to 30 HW. P-car gets the best mileage of the bunch... 02 4runner and a 95 2500 Dodge Ram...