Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Got speedometer recalibrated today

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 90K5, May 30, 2002.

  1. 90K5

    90K5 1/2 ton status

    Joined:
    Jun 1, 2000
    Posts:
    3,719
    Likes Received:
    0
    Location:
    Lubbock, TX
    I have a '90, so its electronic...got it done at a shop today for $100, charged $45 for recalibrating the stock one, so they can be modified to work...I know there were several people on here who are interested in this...a new one was only $85, plus the $55 in labor, but they got mine to work...might yank it out someday and see wha they did if anyoen needs to know...shop is in carrolton Tx, if anyone needs the # I can give it.
     
  2. K5Jimmy

    K5Jimmy 1/2 ton status

    Joined:
    Sep 21, 2000
    Posts:
    1,141
    Likes Received:
    0
    Location:
    Lake Dardanelle/Logan Co, Ark
    Sounds cheep enough.....I could use the number.....did they do it while you waited, or did you have to leave it?....Thanx...
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,980
    Likes Received:
    189
    Location:
    Roy WA
    Was this to change the speedometer to read correctly with different size tires or?

    Different size tire "calibration" IIRC even with electronic speedos, is still done at the speedo "fitting" on the t-case, with the driven gear.

    I'd like to hear more on this, I suppose maybe it could be done at the gauge itself, but that would seem like an awful lot of work, GM would have had to have a different cluster for each gear ratio, as opposed to just a different driven gear.

    Speedo head calibration is typically only done when putting a higher MPH sticker on the speedo face, to get the 85MPH head assembly to actually read the correct MPH.
     
  4. 90K5

    90K5 1/2 ton status

    Joined:
    Jun 1, 2000
    Posts:
    3,719
    Likes Received:
    0
    Location:
    Lubbock, TX
    I changed the gears and tires, there is no gear on mine, its all electronic. The place is called Autocraft, number is 972-466-6200. Located near I-35 and Valwood, and they did it while I waited, took about an hour or so.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,980
    Likes Received:
    189
    Location:
    Roy WA
    Theres gotta be something somewhere based on output shaft RPM. So either they went to a reluctor ring (like the ABS rear diffs) or they had a speedo gear driven generator that varied output voltage depending on RPM, in place of the cable. OR they used something entirely different, but I'd be kinda surprised if they went with a reluctor ring in a '90. (would mean probably some kind of different output shaft versus cable driven 241's) Could happen, but I'd like to know for sure how that was driven.

    I've got an electric speedo cluster I'd like to swap in place of my cable driven, but I've got the NP205. If the vehicle speed input is from a generator mounted in the same place as a cable, I might be able to use a stock piece, but if its a reluctor ring or something else, I'll have to go aftermarket....
     
  6. woody9

    woody9 1/2 ton status

    Joined:
    May 27, 2001
    Posts:
    602
    Likes Received:
    0
    Location:
    Howell, MI
    not sure if this will help, but my 91 takes an adapter that you clip specific pins on to make it all work depending on the ratio/tire size/etc.
    The kit from GM to do it was about $40 or less, and an be used '3 times'. THink this has to do with the number of adapters given, but also involves pulling the dash panel to get to back of speedo.

    Haven;t yet done it.. but have the parts on the shelf. Waiting for the right time to do it (and think i'll give it a wag this weekend!). Have to get all the other junk out of the way (such as tach, trailer brakes, CB, etc...)
     
  7. GRINCH

    GRINCH 1/2 ton status

    Joined:
    Jan 30, 2001
    Posts:
    1,951
    Likes Received:
    0
    Location:
    Helena, MT
    What they did is jumper some pins in the DRAC, It's a box located under the dash by the ashtray.. I had my 90 done and got to watch the process. I know the books and part dealers talk about the jumper pins on the back of the speedo, but it doesn't work that way. Mine was done for about they same price as 90k5.
     
  8. 90K5

    90K5 1/2 ton status

    Joined:
    Jun 1, 2000
    Posts:
    3,719
    Likes Received:
    0
    Location:
    Lubbock, TX
    Yeah, they said something about the DRAC, didn't know what it is though...probably the same thing as the VSS...from what I've heard and seen.
     

Share This Page