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  1. #1
    home of the dislexic fingers breon's Avatar
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    can map sensor go partially bad??

    i have been trying to tune my turbo set up with my power commander...

    it has an auto tune set up on it..

    it corrects the af using the rpm it picks up on from the injector pulse.. and the varible output signal comming off the map sensor...you set up the table where you want the af to be at any given rpm and boost or vac level..it uses the o2 sensor to se where it acually is....if it sees the af isnt what you told it to be more than 2 times it does a calculation and adjust the injector pulse to get it to where it should be..up to 20% is where i have the setting to be max trim..at one time....then you go accept the changes..and go again... it is working beautiful so far... but it was rich up top i know it has plenty of fuel ..it tuned the low end perfectly ..but the top end was 10.9.. when i called up the table you could see where it changed the numbers in the table..on the low end..it wasnt changing..anything above 10 to 12 psi.. so i started manually changing the numbers to pull fuel up top it never budged.. so that led me to question either the software or my map sensor..

    so i took a old usb cable ..stripped the red and black wires..that creates a 5 volt signal ...took that 5 volt signal with the power commmander hooked up and the key on looking at the screen i put 5 v to the input to the power commander ..it saw it and the higlighted block in the table went to 20 psi..ok that is what it is suppposed to do..tells me the software is working..

    now the sensor..put the 5 volt to the referance in port on the sensor.. a meter on the vaible out side..grounds in the middle..and took a piece of hose and conncted it to the input of the sensor..as if it were in the manifold..so i could introduce boost or vaccume and see what it was doing..it seems to work at 0 it is outputing 1.9 volts as it should....and as hard as i could suck on the hose it went to 1.35 so the end seems to be ok..i took my compressor and turned the regulator down to 20 psi...and hooked the line to it ..and only got 2.35 v ...it is a 2.5 bar sensor..at 20 psi it should have been close to 5 v..out..i turned it up to 30 psi..and only got 3.4 v..

    so that is what i have done and why i think i need a new map sensor..could crud get in there and keep the diafram from moving correctly..


  2. #2
    Moderator beerdart's Avatar
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    The answer is yes. I had one the other day that was reading 6psi on BUDS static not running and the engine would start but would not stay running no codes either I guess its ok to run the 4-tec at the top of Mt Everest. LOL. Static not running it should read around 14psi or atmospheric. We change the MAP and for the first time the beast came to life..

  3. #3
    home of the dislexic fingers breon's Avatar
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    weather you ride a seadoo yamaha or kawi..and would love to see a power commander for your application send a nice e mail to this guy ..and ask for them to make one for us...for the money you cant beat what it can do...if enough people show intest..maybe they will make one specific...mine is for he 4 tec snowmobile..it doesnt work out of the box you need to change a couple things..

    [email protected]

  4. #4
    home of the dislexic fingers breon's Avatar
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    like yours it starts runs fine..no codes ...thing rips..just cant get the af to adjust up top ..i allways thought it was it works or it doesnt...well i guess..i will have to get one..

  5. #5
    blackvr's Avatar
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    stock map should read 4.7 volts at 22 psi.

  6. #6
    Moderator beerdart's Avatar
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    MAP voltage map posted in another thread..

    this is courtesy of cal highpsi..if you live in fla and need your rude controler set up ..he is the guy to do it for you....

    Voltage vs MAP
    Here you go guys! This should probably be made a sticky.

    1.0 = 16" vacuum
    1.2 = 14" vacuum
    1.3 = 12" vacuum
    1.4 = 10" vacuum
    1.5 = 8" vacuum
    1.6 = 6" vacuum
    1.7 = 4" vacuum
    1.8 = 2" vacuum
    1.9 = 0 psi
    2.0 = 1 psi
    2.1 = 2 psi
    2.2 = 3 psi
    2.3 = 3.5 psi
    2.4 = 4 psi
    2.5 = 5 psi
    2.6 = 6 psi
    2.7 = 7 psi
    2.8 = 7.5 psi
    2.9 = 8 psi
    3.0 = 9 psi
    3.1 = 10 psi
    3.2 = 10.5 psi
    3.3 = 11 psi
    3.4 = 12 psi
    3.5 = 13 psi
    3.6 = 14 psi
    3.7 = 15 psi
    3.8 = 16 psi
    3.9 = 16.5 psi
    4.0 = 17 psi
    4.1 = 18 psi
    4.2 = 18.5 psi
    4.3 = 19 psi
    4.4 = 19.5 psi
    4.5 = 20 psi
    4.6 = 21 psi
    4.7 - 22 psi

  7. #7
    Moderator RX951's Avatar
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    Thats good info above. I say sticky in case there is a need for reference.

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