am I running rich???

[356robo]

I did a freeway trip mileage check for the first time and got about 16 mi/gal crusing at 70-75 mph and 3000-4000 rpm. Is this about right for a 2.2, S pistons & cylinders, E cam?

I don't really care about the mileage but am wondering if it's running rich.

Thanks in advance,

Rob

[edmayo]

The last time I checked mileage on my 72 S was 20 years ago, at that time (and on that real gas) I would get 18 to 19 at steady 70 cruise. Since nat'l speed limit was 55 that was pressing your luck. Don't know what today's gas will do, I'm sure it's less.

[drwhosc]

I have a 71E, and I get about 19-20 with that type of driving, but my speedo may be off. GPS says about 5%. When I do just highway I go about 220 - 240 miles on a tank about 12 Gals. So getting close to 20. that is using mile markers

With the black soot on the back of the car, I know I am running rich


Must be those S Pistons...

[Flieger]

Is your RPM transducer, throttle microswitch, and shut-off solonoid on the MFI pump working?

If any of these components is not functioning properly, you are dumping raw fuel into the exhaust when you are off throttle. This results in many backfires and Buerzels, ask me how I know.

When I fixed my off-throttle fuel shut off system, I noticed a great improvement in drivability- more engine braking, snappier performance, cleaner exhaust, and a more lean and mean sound.

I also noticed a nice improvement in fuel milage considering how fast I drive.

[daepp]

I just got 21 mpg on my way home from SLO. 75 mph, rebuilt 2.4 T/S with MFI.

[356robo]

Max,

No MFI here. Just old fashion Webers.

Rob

[Fritter]

I get 15-16 around town, 18 mpg on the highway with my 2.2T with webers.

I tend to drive it on the more aggressive side.

And lots of spitting from my loose throttle shafts. Carbs will be redone this winter.

[911s55]

Rob

Mileage is not an accurate indicator of running rich especially with webers, they like gas.
My 2.7 w/webers does about 3,600 rpm at 70 mph and gets similar results as you. If I drive aggressively in any gear and speed, not so good.