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Air/Fuel Ratio Monitor

Discussion in 'The Garage' started by mudbog42, Sep 12, 2006.

  1. mudbog42

    mudbog42 1/2 ton status

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    Has anyone used of those air/fuel ratio monitors that plug into where the o2 sensor goes?:confused:
     
  2. rcamacho

    rcamacho 1/2 ton status

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    I've used a narrow band - pretty worthless. Go with a wideband if you're serious about tuning.
     
  3. 1979jimmy350

    1979jimmy350 1/2 ton status

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    if your are that worried about your air fule ratio you also might want to look in to a EGT sensor
     
  4. mudbog42

    mudbog42 1/2 ton status

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    What is an EGT sensor?:dunno: Are they expensive?:confused:
     
  5. 1979jimmy350

    1979jimmy350 1/2 ton status

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    exaust tempature sensor, a cool exaust is rich and a to hot is lean. just glancing at a summit catalog they are around $100
     
  6. Shazam456

    Shazam456 Registered Member

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    o2 sensor

    Basically all you need to read is voltage. The LED displays they sell are way over priced and not accurate. I wired in a digital display voltmeter,they are dirt cheap. You need to be a little less than 6 volts for a proper mixture. Also if you have headers you need to get the heated three wire o2 sensor that ensures the sensor is at the proper operating temperature.
     
  7. mudbog42

    mudbog42 1/2 ton status

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    Where would I hook the voltmeter into for a proper reading and I do have headers but it has a one wire o2 sensor
     
  8. Shazam456

    Shazam456 Registered Member

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    correction

    Just solder a tee splice from the one wire on the o2 sensor to the positive on the voltmeter and negative on the voltmeter to ground. Also I should have said a little less than .6 volts. The o2 sensor needs to be over (I would have to look up the value) degrees in order to function properly. Most headers cool quickly and your computer then puts the air/fuel mixture into an estimated bypass mode. This may cause you to fail the curb idle test. You can try it out by disconnecting the pig tail on the sensor and test the voltage between it and the truck body. Remember the computer isn't getting any input when the sensor is disconnected.
     
  9. jolane

    jolane 1/2 ton status

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    I just data-logged my 86 Burb a week ago with my LM-1 wideband setup. To do this I built a new exhaust system (2 into 1), and put the bung right after where the two meet.

    The Innovate LM-1 is expensive though. I also used the RPM kit and inductive pickup. I look forward to tuning it more though after replacing the intake and carb. Right now my AFR is all over the place, mostly rich though. At times it is in the 10:1 range, WHOA! Better gas mileage and performance here I come...

    Joshua
     
  10. bigblock72

    bigblock72 1/2 ton status Premium Member GMOTM Winner

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    The only way to get any worthwhile information is to use a wideband 02 sensor. The narrow band sensors are only accurate around 14-15:1. EGTs aren't that helpful because there really isn't a temperature to air fuel ratio correspondence, engine load, timing, fuel all can cause exhaust temps to change. If you're serious about tuning accurately buy a wideband, just be careful not to overheat the sensor and don't run the engine unless the wideband controller is on or you can ruin the sensor.
     

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