I posted this in the electronics section as well but I figured I would post it here as well since my car is a TPI. I just got my air/guel gauge from summit. It is the autometer cobalt series. I got it hooked up but something doesn't seem right with it. I read the instructions and it says it is normal for it to jump around but mine will go up as far as it can go then it will go down as far as it will go while I am driving. Sometimes it isn't reading anything then it will come back again. If I slam on the gas it reads normal to just a little rich but if I am cruising it seems like is going crazy. If I have it in park it seems to work just fine but it only acts crazy when I am driving. Please let me know if anyone elses works this same way. If not please let me know how yours works. I have an 89 Firebird Formula 350. I have checked all the connections and everyone one of them is tight. On the O2 sensor it only has the one wire coming out of the sessor into the connection then one wire coming out. I hooked the gauge wire up to the wire after the connection. Please let me know if I have a bad gauge or maybe a bad O2 sensor.

 

You shouldn't post in multi forums, i replied in your electronis post. Its normal, like i said, due to us not having a wideband O2 sensor.

 

This is normal for the air/fuel ratio guage, mine does the same. I think it turned out to be a $58 light show.

 

From the Auto-Meter Air/Fuel Ratio Guage Manual:

The on-board computer or Powertrain Control Module (PCM) monitors the voltage from the oxygen sensor. If the PCM sees an oxygen sensor voltage greater than .450V, it immediately starts to reduce the amount of fuel that is metered into the engine by reducing the on time to the fuel injectors. When this happens, the A/F ratio starts to go in the lean direction, and the oxygen sensor voltage starts to go down. When the voltage drops below .450V, the PCM immediately starts to increase the fuel metered to the engine by increasing the on time to the fuel injectors to produce a richer A/F ratio. This occurs until the oxygen sensor voltage goes above .450V. This repeating cycle happens very fast (many times per second). The PCM is said to be in closed loop. It is constantly monitoring the oxygen sensor voltage and adjusting the on time of the fuel injectors to maintain a STOICH A/F ratio. Since the oxygen sensor output is very accurate and sensitive at the STOICH A/F ratio, it will cause the A/F meter LED's to bounce back and forth rapidly. A very small change in A/F ratio causes a large change in oxygen sensor voltage as can be seen on the graph. This rapid cycling is normal when the PCM is in closed loop and trying to maintain a STOICH A/F ratio.

 

with all that said i have one and it for the most part does even read anything not even on warm up. i just did a tune-up and all the bars i used to get are gone. i get a green reading at wot. im i lean or im i burning all the fuel in the chamber with my setup.