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Thread: LM-2 acting weird

  1. #1
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    LM-2 acting weird

    i got a loaned LM2, im using the adapter that goes at the end of my exhaust, but the scanner is giving me weird readings, the hand held reads huge numbers like 35 and 50 at idle (reads 20.4 on free air) but on the vcm scanner it says a number closer to what id expect like 14.7-15.3 at idle, which looks to me more in line to what my fuel trims read (14.66 commanded with +/- 3 stft and 0 ltft) im at a loss here, im supposed to make what the scanner reads the same as what the handheld does, but it seems the handheld is what is reading weird.

    is this a common problem?
    read the manual and it didnt say anything about that, is it the sensor going bad?
    Is there a different setting for when its used on the exhaust tip?

  2. #2
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    I don't like the ones that clip onto the exhaust pipe. Depending on cam and etc., there is an opportunity for it to see fresh air and skew the numbers. They are ok for WOT pulls on a vehicle that is already tuned and you are just checking AFR, but IMO, not for tuning.

  3. #3
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    Quote Originally Posted by waynehartwig View Post
    I don't like the ones that clip onto the exhaust pipe. Depending on cam and etc., there is an opportunity for it to see fresh air and skew the numbers. They are ok for WOT pulls on a vehicle that is already tuned and you are just checking AFR, but IMO, not for tuning.
    the thing is fresh air shows at 20.4, but while idling it changes between 25-35 and 50, i made sure it was on gasoline and did the calibration procedure as the manual states but still having those weird lectures, i tried holding the car at 2000 rpm to see if it was fresh air messing with the lectures, handheld showed 16 while scanner shows around 14.8 and my fuel trims +/- 3

  4. #4
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    Agree with previous though.. not a fan of sticking them in the exhaust tip

  5. #5
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    Fresh air the wideband should show 20.9 AFR. Of course it needs to be in free air, not in the exhaust, or even in the exhaust clamp thing it screws into

    Widebands read lambda, then the scanner multiplies out the lambda to get what ever setting you want, like gasoline of 14.7:1. ie Lambda 1 x 14.7=14.7:1

    If the scanner shows differently than your HP Tuners, then your HP isn't setup correct. Go back and figure it out. Could be offset. Could be a ground issue. Either way, they should read the same

    Depending on cam, exhaust, etc. holding 2k might not be enough to keep the wideband from seeing fresh air and skewing the numbers. I've even seen exhaust systems bring in their own fresh air the way they are made or assembled.



    Just remember everything you have is a tool, not an end all be all. Tools can be inaccurate or used wrong, and data delivered incorrect. A good tuner, or etc, will know when their tool isn't sufficient or etc. For example. I have a I don't know how many thousand dollar Mustang Dyno. Customer brings me their car to tune. Most of the tuning is not done on the dyno. A dyno is just a tool. It is not the end all, be all to tuning. I also don't only use a wideband. Point is, you have to know which tool in your toolbox to use, and when.... Experience dictates that.

    ...Good on you for noticing there is an issue with your wideband