What is an A/F meter?

An A/F meter is simply a voltmeter, hooked up to the oxygen sensor. Most A/F meters are simple bar-graph displays, although some have LCD displays. Since the

Installing an A/F meter is as simple as connecting the meter to power, ground and the oxygen sensor signal. Owners of precise meters will want to be certain to get a good ground, since ground offsets may affect the A/F meter readings.

1Gs have a test connector, located in the passenger side of the dash, that is useful for A/F meter connections. This wire can be located by following the directions on Brad Bauer's O2 sensor wire PDF.

2G owners need to connect to the ECU wiring in order to monitor A/F ratios. You can find the correct wire by:

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Steps to Install an Air-Fuel Meter for the 2G Turbo Talons and Eclipses 

Tools Needed:

One Phillips screw driver and three plastic T-connetors from radio shack (if your A/F gage kit does not already provide them).

1. Remove the driver's side access panel from the center console. There is one Phillips screw and one push-in plastic screw that holds the access panel on.

2. There are four plastic connectors plugged into the ECU, directing a myriad of wires going to and returning from the control sensors and relays. Connector 1 has 26 terminals, connector 2 has 16 terminals, connector 3 has 12 terminals, and connector 4 has 22 terminals. The terminal numbers are shown below. (Look at the ECU with your head under the steering column, with your left ear pointing to the floor. The connectors are from left to right, connectors 1, 2, 3, and 4.)

2G Turbo DSM ECU Terminal Numbers

Connector 1
1 2 3 4 5 6 7 8 9 10 11 12 13
14 15 16 17 18 19 20 21 22 23 24 25 26

Connector 2
31 32 33 34 35 36 37 38
39 40 41 42 43 44 45 46

Connector 3
51 52 53 54 55 56
57 58 59 60 61 62

Connector 4
71 72 73 74 75 76 77 78 79 80 81
82 83 84 85 86 87 88 89 90 91 92

4. The hot wire to power up the A/F gage should be teed onto the ECU power supply wire at terminal number 25. The ground wire for the A/F gage should be teed onto the ECU ground wire at terminal number 92. The air-fuel signal wire for the A/F gage should be teed onto the front O2 sensor return signal wire at terminal number 76.

5. Replace the access panel on the center console. You're done! Happy boosting!

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Standard O2 sensors are pretty useless to monitor. Get a wideband O2. [[Why do I need a wideband O2 sensor?]]