VSS/DRAC Question

Discussion in 'The Garage' started by rpellicer, Jan 18, 2005.

  1. rpellicer

    rpellicer Registered Member

    Joined:
    Dec 20, 2004
    Posts:
    38
    Likes Received:
    0
    Location:
    Susanville, CA
    Hi,
    I'm considering making mods to the DRAC as some of the posts in the forums suggested. My problem is, there seems to be some conflicting info as to whether my vehicle uses a 2 or 40 pulse VSS. It's a 91 Blazer w/ 350TBI/4L60/NP241. Does anyone know for sure, or is there anything I can check to be certain? Thanks.
     
  2. Russell

    Russell LLY Escalade Status Premium Member GMOTM Winner

    Joined:
    Jun 23, 2000
    Posts:
    8,118
    Likes Received:
    814
    Location:
    Edmonton, Alberta
    Build(s):
    2
    Alright, I am not 100% sure here... But, If I had to guess, I'd say that the truck came with a 4 pulse VSS, then used a DRAC to convert to whatever signal the different systems needed, starting when they switched to an electronic speedometer.

    http://www.chevythunder.com/fuel%20injection%20elect.%20pg%20B.htm

    There is some VSS info on this page, just scroll down a bit. Shows pictures of the different types of VSS, so you can visually confirm it.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    27,834
    Likes Received:
    434
    Location:
    Roy WA
  4. rpellicer

    rpellicer Registered Member

    Joined:
    Dec 20, 2004
    Posts:
    38
    Likes Received:
    0
    Location:
    Susanville, CA
    Thanks for the clarification. What threw me off was an article published by JTRthat stated that all TBIs through '91 used the 2 pulse.
     

Share This Page