Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

Map sensor question??

Discussion in 'VR - VS Holden Commodore (1993 - 1997)' started by UN4TOLDVRSS, Sep 6, 2008.

  1. UN4TOLDVRSS

    UN4TOLDVRSS un4toldvrss

    Messages:
    21
    Likes Received:
    0
    Trophy Points:
    0
    Joined:
    Feb 13, 2007
    Members Ride:
    VR SS
    Hi Guys,
    A mechanic i was having a chat with recently said that the MAP sensor hose has to be a certain length, otherwise thecar performance will be affected. Does anyone know how long it should be?
     
  2. Chirpstr

    Chirpstr A new project attack

    Messages:
    1,392
    Likes Received:
    4
    Trophy Points:
    0
    Joined:
    Sep 18, 2007
    Members Ride:
    VR Berlina M5, VP M5
    Enough so that it sits flush on each end. (not stretched) Should be roughly 30cm.
     
  3. KiWi1

    KiWi1 11.00@126 Miss dat ****

    Messages:
    119
    Likes Received:
    1
    Trophy Points:
    0
    Joined:
    May 27, 2008
    Location:
    HIGGINS RACE DEVELOPMENTS
    Members Ride:
    Dead 11sec VX SS, Defected VP Ute
    I copied and pasted this, as i roughly know, but factual is better than half factual LOL

    MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR. The MAP sensor is mounted on or connected to the intake manifold to monitor intake vacuum. It changes voltage or frequency as manifold pressure changes. The computer uses this information to measure engine load so ignition timing can be advanced and retarded as needed. It performs essentially the same job as the vacuum advance diaphragm on an old fashioned mechanical distributor.

    On engines with a "speed density" type of fuel injection, the MAP sensor also helps the PCM estimate airflow. Problems here may cause an intermittent check engine light (light comes on when accelerating or when the engine is under load), hesitation when accelerating, elevated emissions and poor engine performance. The engine will run with a bad MAP sensor, but it will run poorly. Some PCMs can substitute "estimated data" for a missing or out of range MAP signal, but engine performance will be drastically reduced.

    MAP Sensor Strategies: Some MAP sensor problems are not the fault of the sensor itself. If the vacuum hose that connects the MAP sensor to the intake manifold is loose, leaking or plugged, the sensor cannot produce an accurate signal. Also, if there is a problem within the engine itself that causes intake vacuum to be lower than normal (such as a vacuum leak, EGR valve that is stuck open or leaky PCV hose), the MAP sensor's readings may be lower than normal.

    Hope that helps bro. Also........

    Same to the effect of running your MAF too close to the TB. Especially with an OTR on a LS1, running the MAF.

    Its also not wise to have your IT sensor too close to anything hot. (best left where it is)

    Simon
     
  4. UN4TOLDVRSS

    UN4TOLDVRSS un4toldvrss

    Messages:
    21
    Likes Received:
    0
    Trophy Points:
    0
    Joined:
    Feb 13, 2007
    Members Ride:
    VR SS
    So to long will send the wrong or inappropriate signals to the pcm?? Think the hose on mine is a fair bit longer than 30cm
     
  5. KiWi1

    KiWi1 11.00@126 Miss dat ****

    Messages:
    119
    Likes Received:
    1
    Trophy Points:
    0
    Joined:
    May 27, 2008
    Location:
    HIGGINS RACE DEVELOPMENTS
    Members Ride:
    Dead 11sec VX SS, Defected VP Ute
    Find a mate, or the likes, with the same car, and compare....

    Or someone on here should take a picture of there car and show you?

    Simon
     
  6. stocky

    stocky New Member

    Messages:
    5,036
    Likes Received:
    77
    Trophy Points:
    0
    Joined:
    Jun 14, 2005
    Location:
    Melbourne
    Members Ride:
    1995 HSV Clubsport T5, 1991 VN Berlina
    shouldnt matter. ive run all different lengths of hose for my map sensor on my supercharged v6. didnt seem to make a difference.
     

Share This Page