Lean running condition Need big help!
 

Well my car has a lean running condition. The car is a 86 Na with no mod other than a k & n drop in. I am currently running very little premix right now. I also had my oil change and fuel filter replaced. The reason i say my car has a lean running conditon is because my 02 sensoer is reading lower than .100v at idle and lower at any thing off idle. I also had the car hook to to a 5 gas analyser and the o2 was over 5%. So the car is running lean for sure. Here is my question what is causing the leaning running condition? If i was to drive this car for a few more days can i run high Octain gas to prevent detenation? Could premix cause a lean running condtion? Does the air/fuel mixture screw do any thing off idle? I also try running the car with the coolent temp off so the car would run full rich and the car still runs lean. So if any one can help it would be great!

It reads low at idle because the airpump injects air into the exaust ports. The exaust ports are prior to the 02 sensor.

Pull the BLUE plug off the Relief Solenoid, then go look at your meter once more. I will probably read closer to something like .5 to .7 volts.

The Variable Resistor is only for idle. With the Blue plug off, watch your meter if its connected to the 02 output, as you screw the screw from lean to rich etc. The meter should respond.

I think if you remove the water thermo sensor.......the ECU defaults to something like a reading of 176 degrees F. So you can see, removing the plug does you no good.

Sorry, I've never seen a RX that ran lean, but then again I have limited experience. I'd make suspect the 02 sensor. They're only about twenty bucks at the auto store. Bosch is a good brand.

I thought the air pump comes in after the 02! I will try unpluging the relief valve thing. The only reason i question your answer is why would the air injection come in before the 02 sensor? I thought the 02 was suppose to detect the exhast reading..... But again i will try unpluging the air pump thing first. Thanks!!! I don't know why i didn't try doing that first. Also thanks for explaining about the air/fuel mixture screw. Does any other people have any other thing to say about the lean running problem?> I am really worry about my baby. I don't want to blow up the engine.

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Man how can i forget to look at the intake diagram............ Stupid! Thanks i wil unplug the valve thing and i will also disable the airpump. Thanks alot buddy i will update you on results!