***Ram jet 350 problem ***

Discussion in 'High Tech Retrofits' started by 72BIGBLOCK, Nov 23, 2016.

  1. 72BIGBLOCK

    72BIGBLOCK Veteran Member

    Messages:
    2,376
    Likes Received:
    83
    Joined:
    Feb 2, 2008
    Location:
    SF
    Thank you for the links but that install manual is for the mefi 3-4 because I don't have the ivuhem sensor :(
    That's why I'm thinking of upgrading

    And I already purchased a service manual but it's very similar I need the oxygen sensor which is why am trying to upgrade the kit
     
  2. czizza

    czizza Veteran Member

    Messages:
    1,011
    Likes Received:
    54
    Joined:
    Jan 8, 2004
    Location:
    N. Massapequa, NY, USA
    So your RamJet does not have an O2 sensor? Your suppose to have it ... if you do not have it you cannot idle nor will it tune correctly.
     
  3. bigdav160

    bigdav160 Veteran Member

    Messages:
    592
    Likes Received:
    6
    Joined:
    Jan 11, 2006
    Location:
    Klein Texas
    02 for idle? Non-heated sensors do not function well at idle.
    I don't know if early MEFI units had input for 02 sensors. My Black Scorpion definitely does not have an O2 sensor.
    I have a wide band on my Suburban. It's used for tuning.
     
  4. czizza

    czizza Veteran Member

    Messages:
    1,011
    Likes Received:
    54
    Joined:
    Jan 8, 2004
    Location:
    N. Massapequa, NY, USA
    In closed loop mode the O2 is used from idle to 3000 RPM and heated option on the O2 is only to get the O2 up to temperature sooner once the O2 sensor reaches temperature it is used all the time and the heater voltage is removed by the ECU because the exhaust will maintain temp.

    If you do not have an O2 then you are a ALPHA-N EFI system which uses the position of the throttle and RPM to know the settings ... the Ramjet is more intelligent then that:

    http://www.hotrod.com/articles/ccrp-0802-electronic-fuel-injection-system/
     
  5. bigdav160

    bigdav160 Veteran Member

    Messages:
    592
    Likes Received:
    6
    Joined:
    Jan 11, 2006
    Location:
    Klein Texas
    No intention of starting a pizzing match but you obviously didn't work on cars during the 1980's. They would fall back into open loop at idle because the exhaust didn't carry enough heat to keep the sensor active. The o2 is really only there to keep the catalytic converter happy anyway. Sure they help with tuning. Who want to carry their gas analyzer in their car? There are plenty of examples of EFI running without an active o2 and still idle and run fine.

    From the little reading I've done, only the latest Ramjet controller, the MEFI-4 has o2 input.
     
  6. 72BIGBLOCK

    72BIGBLOCK Veteran Member

    Messages:
    2,376
    Likes Received:
    83
    Joined:
    Feb 2, 2008
    Location:
    SF
    Yes the mefi 4 has the oxygen sensor the model I have didn't come with one

    But aside that I think I'm having an issue with the fuel lines because it sounds like theirs air in the fuel when I try n start it
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.