OK, I have had it........ milage problem/question....

[Anonymous]

OK, I bought this thing (1979 'stang) to drive back and forth to school and get decent milage, on the interstate it is not to bad, I get about 17-20 mpg depending.

I have been off from school and I am getting 10-12mpg in the city.

What can I do? Already has new plugs, wires, cap, rotor. Performance be damned I have the Ranger (302/c4 w/ 100 shot) when I want to go fast so all I am worried about is economy and I know it won't ever be "the best" but it has more in it then this.:

1. What are you guys getting?

2. Where should vaccuum advance be hooked for best economy?

3. What timing helps economy?

4. Which carb is going to be cheap and give me the best fuel economy (this may not happen as the $$$ is short)

5. Any other cheap tips?

 

[BIGREDRASA]

What engine, transmission and tire combination are you running? :

 

[Anonymous]

sorry forgot it has been awhile since I posted............. 200/c4 with I think 3.27 gears. Tires I think are a 245/60/15 (I think...... they are slightly larger than stock)

 

[MustangSix]

The later 200 engines from the mid seventies to the end of production in 1983 got VERY poor mileage in some cars. It was a miserble engine in the Fox Mustang because it was saddled with so many emmisions devices, a poor timing curve, and low compression.

The CR should be 8.0:1, but in reality is might be as low as 7.5:1 because of tolerances. That's going to be hard to deal with without a piston or cyliinder head swap, so you need to focus on other efficiencies.

First, look at the ignition. Set the timing to 12-14 degrees BTDC static. Make sure all the components are in good shape.

Then look at the carb. If the float level is too high you may be wasting fuel. You may need a rebuild. If you still have the emissions equipment atached, make sure all the hoses are in good order. If emissions are'nt a concern, a YF or RBS might be a better carb.

The exhaust on these early Fox inlines is dismal. Replace it with the right side of a later GT with a turbo muffler and if you have one, get rid of that hellish thermal reactor.

Lots of other things contribute to mileage, but in city driving weight is more important than aerodynamics. Get rid of any extra junk you might be carrying around. Keep the tires properly inflated, and get a good four-wheel alignment. Drive smoothly, anticipate stops.

 

[Anonymous]

Thanks man that kinda confirms what I had already thought. Looks like bump the timeing and focus on exhaust and carb.

 

[jwb68c]

I don't think the short fat tires are helping much either, on my Falcon w/170 3spd I went up 1.5 mpg with 195/75R14s from 235/60R15s. Acceleration was better also with the skinnies, I'm only running 2.79 gears, the tire height remained pretty close between them too. Jason

 

[Asa]

go read this too, might help
http://fordsix.com/forum/viewtopic.php? ... ght=module

 

[Anonymous]

Sweet I think I may try the module thing........ so where can I get the sensor? the Module is easy, but the sensor is going to be a little harder.