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Thread: MAP sensor not registering a reading?

  1. #1
    Tuner in Training mattster03's Avatar
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    MAP sensor not registering a reading?

    I just got my LS1 Swapped RX-8 on the road yesterday and did a little logging with the VCM scanner. It was running super rich in open loop but once it warmed up to closed loop it leaned out as the O2 sensors took over commanding like -33% fuel. So I was trying to get to the bottom of why it was running super rich and I noticed that my stock MAP sensor was not reading at all during the short drive. Like, no little pointer on the MAP gauge on the dashboard, and just filling up the 15kpa row on the histogram as it went thru the range of RPMs. I did some basic trouble shooting, checked for 5V at the sensor, checked the signal pin at the PCM, made sure it wasn't plugged, etc. I have a new MAP sensor on it's way from Amazon to try, but in the meantime, can anyone explain this? Much thanks.
    Last edited by mattster03; 07-20-2020 at 10:09 AM.
    1993 Mazda RX-7 R1
    LS1/T56, EPS 230/238 + PRC Stage 2.5 5.3L Heads
    10.825 @ 129, 1.58 60ft

    2004 Mazda RX-8
    LS1/T56 "Family Burnout Machine"

  2. #2
    Tuning Addict 5FDP's Avatar
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    Delete the channel, re-poll for supported parameters in the scanner and add the channel back in. See if it starts working again.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Tuner in Training mattster03's Avatar
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    Quote Originally Posted by 5FDP View Post
    Delete the channel, re-poll for supported parameters in the scanner and add the channel back in. See if it starts working again.
    This worked. Thank you for the helpful suggestion!
    1993 Mazda RX-7 R1
    LS1/T56, EPS 230/238 + PRC Stage 2.5 5.3L Heads
    10.825 @ 129, 1.58 60ft

    2004 Mazda RX-8
    LS1/T56 "Family Burnout Machine"

  4. #4
    Potential Tuner
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    NC
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    how do you re-poll for supported parameters idk how to do that or i do but dont know the lingo thanks

  5. #5
    Tuning Addict 5FDP's Avatar
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    Click the vehicle tab in the scanner, it's in there.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.