MAP or No MAP

Discussion in 'Mechanics Garage' started by Expvet, Mar 14, 2019 at 12:37 PM.

  1. Expvet

    Expvet New Member

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    I am going to do a starter valve sync soon and have read different approaches as to whether the MAP electrical connector and it's vacuum hose should be attached or disconnected. The manual shows that they both should be, but I have read on VFRD and VFRWorld varying opinions on as to if they should or should not be attached. Any insights?

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  2. Expvet

    Expvet New Member

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    Shameless bump
     
  3. RllwJoe

    RllwJoe Member

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    I didn't do that when I "synced" my '98. Maybe I should have?
     
  4. SweViffer

    SweViffer New Member

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    My guess is that a disconnected MAP sensor makes the ECU behave exactly like a connected MAP sensor without any vacuum, in other word in limp home mode. No difference. A further guess of mine is that the service manual recommends that both the MAP sensor and the vacuum line (that is disconnected on the other end) to be connected so that it wont fall out of place. The vacuum line is a b***h to fit into place with an hot engine, and you want to test your synchronization immediately don't you? :)

    I did mine yesterday with both the MAP and IAT sensor connected, and it worked just fine as long as I didn't turn the engine off and restart it. When I did that it took some time for the ECU to catch up to what I was doing, and while undecided on the best way forward it produced an idle of 900 rpm. After a minute or two it was back to the adjusted 1200 rpm. No issues with all of the vacuum line reconnected.
     

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