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.

Holley Replacement TBI (Assistance needed)

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 88K5Rhododendron, Mar 5, 2001.

  1. 88K5Rhododendron

    88K5Rhododendron Registered Member

    Joined:
    Sep 21, 2000
    Posts:
    25
    Likes Received:
    0
    Location:
    Outside of Rhododendron, OR
    I replaced the old TBI with a Holley replacement, because it is less expensive and is suppose to have better performance... Well it would seem it likes to use more gas, but the car overall is not performing very well. When I start it cold it runs so richly that you can smell the unburned gas in the exhaust, as well as the occasional backfire. When it warms up to normal the throttle is very sluggish and off the line it hesitates (I think this means it is too rich)... In any case I was wondering if there was some way for me to make it run more lean because the milage and performance is really starting to bug me (6 or 7 mpg)...

    Any help would be much appreciated!

    Matt

    gasoline4life! Or rocket fuel... I could see my blazer with some rockets on it... :)
     
  2. Blazer79

    Blazer79 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    1,816
    Likes Received:
    0
    Location:
    Guatemala, Central America
    Did you replace the O2 sensor when you changed TBI? The O2 sensor is the nose of the system. It helps determine if it's running too rich or lean.

    Hope this helps

    <font color=blue>//////
    <A target="_blank" HREF=http://blazer79.coloradok5.com>http://blazer79.coloradok5.com</A>
    </font color=blue>[​IMG]
     
  3. Stoopalini

    Stoopalini 1/2 ton status

    Joined:
    Oct 17, 2000
    Posts:
    999
    Likes Received:
    0
    Location:
    Austin, Texas
    Try timing the engine.

    I'll bet the timing was off to begin with -- to compensate for the worn out TBI unit.

    Now that you have a brand new one, I would assume the timing needs to be adjusted.

    Good luck,

    Thomas.

    -- '84 K5 Blazer --
    <A target="_blank" HREF=http://Stoopalini.coloradok5.com>http://Stoopalini.coloradok5.com</A>
     
  4. Executioner

    Executioner 1/2 ton status

    Joined:
    Feb 22, 2000
    Posts:
    1,530
    Likes Received:
    0
    Location:
    Temp. Ft. Walton Beach Fl. home=Tucson, Az.
    You might have to play around with fuel pressure
    Good luck
     
  5. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    It sounds as if the injectors on your new TBI have a higher flow rate than the stockers had. Since your computer doesn't know this, it is still using the parameters for the stock injectors, which would mean the engine will run rich.

    Was this supposed to be an exact replacement TBI or just a generic Holley ProJection TBI? If the latter, then it could be that you need a new PROM for your computer to compensate for the difference in fuel flow rate. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     

Share This Page