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Thread: 2015 Jeep Wrangler Lean AFR

  1. #1
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    2015 Jeep Wrangler Lean AFR

    Hi

    I have a problem with a 2015 Jeep Wrangler that has Air intake and catback system only. I have not messed with injectors data nor with InjPw vs Fuel Mass tables. NN is on and the problem is that the AFR is always at 19 ! Even WOT enrichment does not seems to do anything when I floor it and it remains the same.

    Usually under closed loop condition AFR should be around 14.7 where with this Jeep it idles at 19 and the LTFT is showing -10%, I've never encountered such issue before and would appreciate any guidance.

    I am suspecting a faulty wide band sensor and would try the sensor on another car today and perhaps installing the sensor in the down-pipe just to role out any doubts in that area

    Many thanks

  2. #2
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    Where is your wideband installed at? if the vehicle is running just fine without issue but the wideband is showing 19 all the time, then I would suspect a faulty sensor.
    JTC Performance - Authorized HP Tuners Reseller
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  3. #3
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    Quote Originally Posted by charcoal03silvy View Post
    Where is your wideband installed at? if the vehicle is running just fine without issue but the wideband is showing 19 all the time, then I would suspect a faulty sensor.
    Sensor installed on the exhaust tip, and it does fluctuate but never below 15 afr

  4. #4
    Tuner Pector55's Avatar
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    Quote Originally Posted by shopard View Post
    Sensor installed on the exhaust tip, and it does fluctuate but never below 15 afr
    I have run into something similar with exhaust mounted widebands due to it reading the fresh air mixing in. It sounds as though the fueling is really slightly rich as indicated by the O2 feedback but the wideband may just be getting fresh air mixed in, making it read false lean.
    2013 Dodge Challenger RT Plus - Shaker

  5. #5
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    Hard to trust a tailpipe sniffer in a lot of setups. Put it in place of a O2 sensor if you can and see what its doing. Or get an additional bung installed specifically for the wideband.
    JTC Performance - Authorized HP Tuners Reseller
    Remote performance tuning

  6. #6
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    Thank all for the support, sensor was okay, the problem was with the location of the sensor, welded a bung and installed the sensor in the pipe and it started showing realistic numbers. One interesting thing I found after calibrating the afr at WOT with this Automatic Jeep is that the ECU will deliver different afr based on the transmission mode. So lets say that I calibrated the afr under WOT in D to be 12.7 and if I move the shift lever to manual shifting, afr will drop to 11.7

    I tried it many times and got consistent result in each mode respectively. any one else noticed this ? It seems that when shifting manually the truck would be considered in sport mode and ecu will demand richer air/fuel mixture.