Installing an Air/Fuel Ratio Gauge
Paradise Garage

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© 2001 Brian F. Schreurs
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In preparation for installing a supercharger on the visiting 1995 Ford Mustang GT, we bought a gauge pod that fits where the clock pod goes on the dashboard. Don't have a clock pod there? That's because you drive one of the wimpy 4.6L GTs that came out later. Stop thinking your car is exactly like ours!

For those of us lucky enough to have a clock pod to remove, it's easy to install this twin-gauge pod in its place. The first hole was going to a boost gauge, of course, but the second hole was wide open. We figured a digital air/fuel ratio gauge would look cool and help us fine-tune the car to boot. And, to make it better, we devised a way to switch between oxygen sensors, so we could monitor both banks! Pretty nifty.

We like the Auto Meter stuff so we ordered up their 2-1/16" electronic air/fuel gauge (#3375). We put it in an Auto Meter dash pod (#10001). To enable the switching function, we got a little switch from an electronics supply house that had two "on" positions and one "off". We also needed some miscellaneous wiring supplies.

The clock pod pops loose with little difficulty.
Remove the center console cover. It pulls off -- be gentle to avoid breaking the cheap clips Ford likes to use everywhere. Disconnect the wires going to the accessory power outlet (cigarette lighter in the old days).

Remove the clock pod. All you have to do is push on the pod from the front; it has clips on the front that hold it down. The clock is wired to the car's power supply; unplug it.

To mount the switch controlling the A/B bank feature, drill two holes in the console cover. Space the holes so that they are close to opposite ends of where the switch will go. Then use a Dremel, a file, a drill, or whatever other object comes handy to connect the two holes and form them into a rectangle that the switch will fit into. It's kind of tedious, but keep in mind that it doesn't have to be extraordinarily pretty: the switch's bezel will cover the cut.

To handle the wiring, you'll have to take the dashboard apart. To get the front fascia off, you must first remove the headlight knob. Pull the knob to its full-open position and look for a slit near the base. Supposedly there's some sort of clip in there that you just loosen with a pick or punch, but we dunno. We just fiddled with it for about a half hour till it fell off. It'd probably be easier to just buy a new one and break the old one off.

The oxygen sensor toggle switch is subtly mounted on the shifter/console bezel.
With the headlight knob out of the way, it's possible to pull the fascia off. It's held in place by two Torx bolts, size T-15. They are located along the upper edge. With those removed, gently pry the fascia off.

The air/fuel gauge needs power, a signal, and a ground. We already had other gauges installed on our Mustang (see the transmission temperature gauge and the oil gauge for details) so we just tapped into those for juice. If you haven't been modifying your car just like ours, you'll need to find a source of ACC-on power under the dash.

The signal wire goes to the switch, since we're setting up a cool dual-readout scheme.

The ground can go to any good ground. Use the structure or tap into the ground wires already present from your other gauges. For all of the wires, it's easier to send them down from the dashboard rather than trying to poke them up from underneath.

Press the switch into the console cover. Wire it up -- our switch had spade connectors, so we used them to make it easy to disassemble later. One wire, as stated, goes to the gauge; the other two go to the oxygen sensors. If your car is an automatic, there's a handy hole in the firewall to the passenger-side of the master cylinder. We're practically running a whole harness through it at this point. If your car's a manual, well, break out the drill.

Our little rat's nest of oxygen sensor wiring.
Run the oxygen sensor signal wires from the switch down to the sensors and splice into the sensor harness. Be sure to splice into the signal wire -- if you don't own service manuals for your car, now's a good time to go get them.

To install the gauge pod, slide the T-bar mount up under the dashboard so that the threaded stud is sticking up. Slide the upper mounting plate onto the threaded stud so that the two bars sandwich the dash, holding the bars in place. Use the conventional nut to hold them together.

Run the wires through the gauge hole on the pod. Connect the gauge and wires. If you are installing two gauges at the same time, prepare that gauge for installation as well. Consider the two gauges and decide which will be less difficult to push into place. Since we were doing the boost gauge with its hard plastic vacuum line, we decided the air/fuel gauge was easier to install.

Put the harder gauge into position in the pod.

Now we have a very cool if somewhat useless digital gauge!
Place the pod over the threaded stud and position it to your liking. Hold it in place by putting the nylon locknut on the threaded stud. Once the gauge pod is stable (keeping in mind that if it's loose, it'll rattle like a dozen marbles in a 2-lb coffee can), press the easier gauge into place.

Keep pushing. Push, push, push! Breathe! Make sure it goes in straight.

Reassemble the dashboard.

Reassemble the console.

Try it out!

The digital air/fuel gauge looks really, really cool, especially at night. As it turns out, that's about all it does. The thing is bouncing around all the time, either at full rich or full lean. This would make sense if we'd stopped to think about it, because your typical oxygen sensor is nothing but an on/off switch that activates and deactivates really quickly. But hey. It looks cool, and it will provide a warning for a very serious problem or a dead O2 sensor. And the pod would look kinda dumb with just one gauge.