You have just finished the installation ofyour new Auto Meter Air/Fuel Ratio gauge, and it is almost sundown. You take your vehicle out for a'test drive to ensure all is well with the install and the gauge is working as it should. The sun has now set and you turn your lights on but the AN Ratio gauge remains dark, except for the LEDs that are dancing back and forth.

What gives?
There is no backlighting to the A/F Ratio gauge whatsoever. Quite simply, there is no room for a socket, bulb, or even the light to reach the. front of the gauge. If you remove the silver tab on the back of the gauge with a small straight head screwdriver, you can see that the PC board is about 3/8" down inside the cup.This leaves very little room to attempt to install a light and socket. Even if you can get a light to fit into this cramped space, your next problem is that the outer diameter of the PC board is about the same size as the inner diameter as the gauge's cup. This will not allow much, if any, light to actually reach the front of the gauge to illuminate the face. This is where the color-coding of the LEDs comes into play.

If you look at the face of the gauge, you will see that the dial face tells you what range the gauge is indicating in. The colors of the LEDs are different in each area as well. By driving during the day and occasionally looking at the gauge's face, you will learn the location of where each range is. At night you will be able to determine what the A/F Ratio is, based on the color of the LEDs.

We have had quite a few inquiries about our new electronic speedometers. One of the greatest features of the electric speedos is that they are fully programmable, which means you can recalibrate them easily if you change your rear-end gear or tire sizes. If you have ever had to change the gear in the transmission to adapt for either of these changes, you will appreciate the ease of the calibration with this'speedo. The overall calibration procedure is quite simple.The critical point of the calibration is measuring a 2-mile distance. Here is a quick review of what the instructions state in more detail;
Make sure the tires are inflated to the
   manufacturer's specs.
To aid in minimizing error try not to
  exceed 45 MPH during calibration (tires
  will slightly increase in diameter with
  vehicle speed).

Obviously, you do not want to break
   traction, as that will also adversely
   affect the calibration.
The load (weight) of the vehicle plays
   into the diameter of the tires, too, so be
   sure to have an average load in the
   vehicle during calibration.
Connections to various vehicles
We offer two styles of senders;
1. #5291 fits most GM and most Chrysler vehicles that may have previously used a cable. Both vehicles share the same size speedometer cable connector (7/8" - 18 THD). Double check to make sure this thread will match what you have on your transmission, to ensure compatibility.
2. #5292 fits most Ford transmissions that have cable outputs, and utilize a retaining "clip" to mount the cable/sender to the housing of the transmission.

Both senders will replace the existing cable, or attach to the cable output of the transmission and produce a signal to drive the speedometer. Most later model transmissions without a cable can use our speedo too.They get the signal DIRECTLY from theVSS (vehicle speedo sensor), NOT from the computer. The signal after the computer is buffered (conditioned) and our speedos will not recognize that type of signal. Connect the speedo directly to the wire that sends the raw signal from the VSS. Finding the signal wire is usually quite simple. The signal wire will produce anywhere from 2V up to 120V DC peak to peak. This can be tested with a standard multimeter (the voltage should increase with the vehicle speed). Otherwise, you can look in a service manual for the signal wire, or if you can't find it anywhere, contact us and we'll see if we have the information.
Speedometer Calibration
Once everything is installed (both wiring and the speedometer) you can calibrate the speedo. A pushbutton is included for the calibration steps, as described in detail in the instructions.The following is a quick review of the steps. Turn off the vehicle if it is on or running.

Press and hold the button.

Start the vehicle.

Once the vehicle is running, release the
   button (the pointer should go to the
   highest MPH reading).

Drive to the beginning of your carefully
   measured 2mile distance, and stop.
Press the button again (the pointer should    go to half the maximum MPH
   reading).The speedo is ready to be
Drive the two miles and stop.
Press the button