Installing an Air Fuel Meter

By Steve Hoult

An air fuel meter is an important part of a highly modified SC. Run lean under boost and you can melt your pistons or cause other costly damage. Installing a AF meter is a fairly simple task. The hardest task is running the wire from the engine compartment to the dashboard.  Once you've run the wire down either the center console or the door channel you have to pass it to the engine compartment.

RUNNING THE WIRE THROUGH THE FIREWALL

There is a grommet through the firewall behind the drivers seat. To get to it you need to follow these step:

1. Remove the drivers head rest by pressing the release button on the inner most post and pulling straight up. Using a 14mm  socket, remove the 4 bolts holding the seat in and remove the seat. Now you'll have room to do the rest.

2. Remove the plastic panel  between the drivers door and the firewall.

3. Remove the C pillar panel (where the itsy-bitsy speaker is) by  removing the seat belt bolt (14mm), remove the palstic rivet by pushing the center in until it hits the detent (careful or it'll break), remove the t-top and take out the two screws on the end cap, unscrew the bottom screw and carefully pull out the panel.

4. Remove the  screws holding down the retainer holding the top of the carpeting and carefully pull up on the aluminum retainers. You can now carefully peal the carpet back diagonally until you can see the  grommet about halfway up the firewall.

5. Moisten the end of the wire and press it against the grommet until it passes through.

Wiring into the Oxygen Sensor

Most AF meters will require (or work best with) a heated O2 sensor. Luckily for us, the SC comes standard with one. These are commonly known as 4 wire sensors. The four wires are colored Blue, White and two Black. The blacks are ground. The white wire is the heater. That leaves the blue wire as the actual signal wire.

The above is from the TWMInduction Halmeter AF30 meter I installed, but the hook up is the same for almost any meter. The wire you splice into is the blue wire on theO2 sensor. Since the current draw of the Halmeter is extremely low, (only two LEDs light at a time) I wired the 12v and ground to the same wires the CD player uses.

If you decide to use the Halmeter like I did, you'll find that the unit is a half DIN height and if you've replaced the stock stereo with a aftermarket unit the Halmeter fits perfectly underneath the CD player. This leaves the right 1/3 for a panel to install an on/off switch and an adjustment knob (function to be determined later). I'll post pictures of my install later.

.