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Map sensor--bugging...


Map sensor--bugging...

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    Map sensor--bugging...

    HEY quys.

    91 LS
    manual 5 speed

    Car turns on but, dies in like less than a minute.
    i accelerate and it like, chocks. it does rev up but, sputters at times.

    SO. when cars about to die i unhook the Map sensor Vacum line as seen in the camera phone pic: Car is much MUCH better, responsive, and doesn't die..

    Check engine light comes on once in a while and only throws a code 5. So i replaced the map sensor 3 times. AND STILL does the same thing.

    checked all vacuum lines,
    did spark plug
    spark wires.
    fuel filter.
    fuel injectors.
    and still acts up.

    am i missing anything???????????
    any info is great, thanks
    Attached Files
    Last edited by pulga37; 16 Sep 2009, 16:27:02.

    Couple questions:

    1) Did the ecu throw a Code 5 BEFORE or AFTER you disconnected that vacuum line?

    2) When you disconnect that vacuum line are you simply disconnecting it? Or are you disconnecting it and plugging the hardline which leads to the throttle body?

    3) Did you follow the step by step procedures in the Helms manual for troubleshooting Code 5?

    4) Have you checked your mechanical timing?

    5) You said you "did" plugs, plug wires, distributor, injectors, and fuel filter. Did you replace all of those things with brand new pieces? Replace them with known good parts from another car? Or did you simply inspect them visually?

    If you didn't start getting a Code 5 till after you disconnected that line then I would expect your problem to be unrelated to the MAP sensor.

    Code 5 is specifically due to a vacuum leak in the MAP system. By disconnecting that vacuum line and not plugging the hardline you are essentially creating a vacuum leak. This could cause the ecu to throw a Code 5. Additionally, the vacuum leak would then supply more air to your engine w/o you giving it any throttle. This could be masking whatever your original problem is.


      THanks for the prompt response COLIN

      1). Cel 5 comes on when i drive the car.... Either with the vacuum line on or off.

      2). Just disconeting the map vaccum line. not plugging any hardline...

      3). only have chilton. ......

      4). Mechanical timing ok......... but will double check

      5). Replaced parts from a known, running strong, Integra B18A

      to do list.
      will double check Mechanical timing.


        Did you thoroughly check all of the MAP vacuum lines for leaks by either replacing them or pressurizing them with a pump? Even the hardline should be checked. You can check that by bypassing it with a longer vacuum hose if need be.

        You've been resetting your ECU I assume?

        The code seems to be showing up intermittently? Meaning that it doesn't come on and stay on immediately. Just sorta happens whenever it wants to?

        Shoot me an email, I've got a present for you.


          1). Yes, checked vacuum lines and replaced the ones I would even suspect of being faulty.

          2). I didn't think of checking the hardline though. I do have an extra one, so i will swap it.

          3). Yes, i have been reseting ECU.

          4). Cel 5 just comes up as soon as I hit the end of my block.

          5). Thanks Colin, just email you. Ready for my birthday present. O yea!


            email replied.


              just did a swap to stock and my cars doing the exact same thing did you ever figure it out?