From left to right what is lean to rich?
(picture below is what I have)

Does anyone know how to install this gauge? I thought there was a post here recently, but for the life of me I can't find it by searching the archives. I'd like to install the vacuum/economy gauge and I have the original tubing. I just don't know where it goes. Thanks for your help.

it's a vacuum gauge, not a mixture picture. the reason for the gas pump icon is because, the more vacuum, the better gas mileage. so, as it's pictured, it's under a full load-no engine vacuum present. when the needle swings to the left, then the vacuum is getting stronger. good luck, chuck.

This is just a factory picture not actual readings from the gauge.
When at idle the needle is all the way to the left. When I accel it
goes 3/4 to the right. Since the vacuume is strong at idle wouldnt
that show that I dont have a intake vacuume leak?

Not neccessarily. :)

The vacuum in the intake manifold goes down (and the gauge goes up) when you step on the gas because you are opening the throttle body. It's like sucking on a straw: there's a lot more vacuum in a straw when you suck with your finger over the end. Take your finger off, and it's hard to really pull a vacuum. Even if you suck a whole lot more, you'll never get the same vacuum.

A fuel economy gauge really measures vacuum, not fuel economy. It's just that fuel consumption tends to go up as the vacuum decreases which is why a vacuum gauge can be used to approximate relative fuel economy.

When you think of it, it's simplicity is actually a pretty elegant altternative to the the expensive computerized version in modern fancy cars that spits a bunch of meaningless numbers at you: Our old jeep would tell us we were getting 96mpg going down the mountain... that's useful... (not!). :)

-Ryan
--
--------------------------
Athens, Ohio
1990 245 DL 130k M47, E-codes
1991 745 GL 280k (Girlfriend-mobile)
Buckeye Volvo Club