Results 1 to 3 of 3

Thread: why is my map reading backwards?????

  1. #1
    Tuner ari666's Avatar
    Join Date
    Oct 2011
    Location
    australia
    Posts
    61

    why is my map reading backwards?????

    my map sensor is reading 100kpa when the engine is off/ignition on. and 0 when its running.

    lololol

    any clues why its doing this? wiring is:
    C- 5V
    B - signal
    A - low ref
    1966 impala. L29 454. 0411 pcm. 2.5" twin system. comp cams XR282HR. ported heads. 1.75 rollers. 60lb deka injectors. bosch 044 pump. standard intake (cos' looks cool in a 66')

  2. #2
    Tuner ari666's Avatar
    Join Date
    Oct 2011
    Location
    australia
    Posts
    61
    map sensor part number: 16249939

    I think it has something to do with me selecting 1bar speed density from the OS menu and reflashing... I switched the +5v and ground on the sensor for a lol, but all it yielded was a non responding gauge.

    so weird. its not just the gauge on scanner, also when in real-time the table reads the same value as the gauge. i.e. the selected cell moves higher in vacuum as the engine is about to die.

    what have I done? and how do I un-done it?
    1966 impala. L29 454. 0411 pcm. 2.5" twin system. comp cams XR282HR. ported heads. 1.75 rollers. 60lb deka injectors. bosch 044 pump. standard intake (cos' looks cool in a 66')

  3. #3
    Tuner in Training
    Join Date
    May 2014
    Posts
    15
    that seams mostly normal to me... at least the 100kpa with key on and engine not running as atmospheric pressure is 101.325kpa at sea level. http://www.princeton.edu/~achaney/tm..._pressure.html

    Although reading 0kpa at idle would not be right. depending on the engine and altitude, baro, temp, ect ect... 30-35kpa should be about normal idle vacuum.