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Thread: Map sensor reading high

  1. #1
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    Map sensor reading high

    2009 Srt4 Caliber. Mpvi2 log shows 13.9 psi koeo, and spikes up to 35psi wot.

    I plug in the Aeroforce scangauge and 0 boost with koeo, and about 22psi boost. Read that it cant be adjusted on another thread that hptuners just sees what info the computer is sending. Well that cant be because I can see it with my own eyes that hptuners is wrong. Any ideas?

    On a side note, went out and bought a new Tial wastegate and manual boost controller trying to get a handle on this boost spike the log said I was having, no change lol.

  2. #2
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    Are you using the BOOST math or looking at the MAP sensor output (BTW there are different MAP outputs on some controllers like "calculated" which can be way off) directly?

  3. #3
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    I'm guessing map sensor output. I just selected the map sensor and added that to monitor. Im new at this.

  4. #4
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    Also when I started adjusting the boost, I went from 15psi on manual boost controller all the way up to 20 and the scan gauges and factory boost gauge read the same. I just use the scangauges for boost past 20 psi because that's max on the factory gauge. I've got it to 28 now, but would like the hptuners log to match.

  5. #5
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    Ah, if you are just looking at MAP don't forget that it measures absolute pressure. So at KOEO the MAP is showing barometric pressure. Boost is a gauge pressure measurement (i.e. barometric pressure is subtracted). If you want to see boost use the math function BOOST. Otherwise take your MAP reading and subtract BARO from it.

    From your original statement "Mpvi2 log shows 13.9 psi koeo, and spikes up to 35psi wot." this translates to a boost pressure of 35-13.9 =21.1psi.

  6. #6
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    Ok cool, thankyou! I also found a Tuning School video on YouTube that shows how to read boost on the log, but you have to enter your barometric pressure of your location. Won't that change almost everyday?

  7. #7
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    Well I'm making progress. So I went and found what the barometer is currently and entered it in hptuner, following the tuning school instruction video on youtube.Now in my log I got it to read 27psi, which is good but it's in negative. As the car accelerates, the boost changes but goes the wrong way lol.

  8. #8
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    You could use the boost math directly, which is not done through the channels but can be added to graphs/charts/gauges. Just go to parameters>math>airflow>boost.
    2.JPG3.JPG
    I have is setup in my gauge section and select the bar graph limits to 0 to 10psi so it only indicates when I am in boost.
    1.JPG

  9. #9
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    Hi guys,
    I just tuned my 2012 Dodge Charger 6,4 SRT8 and an error code come up.
    P0129 Barometric pressure too low. I ve been reading alot here, but I'm not sure I was able to underdstand what Ive read. (Im so new wat this).
    Here are my stock and tune files.
    Can somebody give an idea what and where should I change?
    EH5566KH factory benstar.hpt
    EH5566KH factory galeto2.hpt

  10. #10
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    Your baro min in engine diagnostics is too high...set it to 0.9V.

  11. #11
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    Thank you Homer,
    I've checked everywhere else, but there...
    There is no error codes now.
    Thanks again

  12. #12
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    You have some other issues with your tune, your MAP high and low values are still stock. Go to the tune repository and look for a 2015 challenger with magnuson tune from Casper. Compare the engine diagnostic tables and make changes as necessary.

  13. #13
    Tuner in Training
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    Thanks Homer.

    I checked,but couldn't find a file for the Challenger.
    I made some changes to MAP high and low values based to another file that I have and used before and worked fine.
    I have to reduce the fuel somehow becaause it is rich now.

    EH5566KH new.hpt