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TBI 350 Timing Issue

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by MudFrog, May 18, 2002.

  1. MudFrog

    MudFrog 1/2 ton status

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    Hey everyone... have a couple questions. I knew my timing was off by a good bit so I adjusted it to 8 which is the factory specs. Before I adjusted the timing it was a good bit above 12. So once I adjusted it to 8 I took it for a test drive and it had no power at all. I could floor it and the engine would bog down and in return I would have no power. So I went and advanced it a little more (my guess is maybe 10?? if that) but just slightly, I never rechecked the actual position either. Once I did this my engine started back firing under full throttle and the engine bogs down pretty bad, sometimes the engine will rev up pretty good but I'm actually losing speed instead of increasing speed. I checked to make sure I didn't accidently unplug anything and I didn't see anything. So can someone tell me exactly what the timing needs to be set at, and what could possibly be causing this?? As it is now it struggles to hit 45 mph.
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    My Chilton's show's 4* BTDC for an 87 TBI 350.

    Rene
     
  3. MudFrog

    MudFrog 1/2 ton status

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    I got 8 degrees from the Hayes manual.
     
  4. 350S10NJ

    350S10NJ Registered Member

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    Unplug the computer first its a brown wire on the passenger side at the front edge of the carpet, unplug it time to zero , turn off the truck plug it back in, then it should be timed correctly
     
  5. Thunder

    Thunder 3/4 ton status

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    Yup. You have to unplug the timing bypass. Your engine cannot be properly timed unless you disconnect it.

    The above post describes the pre TBI carbed computer controlled trucks.

    On the TBI trucks it is a brown wire with a black stripe.
    It is located on the drivers side in the engine compartment Firewall By the power brake booster. It is a connector sticking out of a thick bunch of wires.
    Pull the connector apart. The "Check Engine" light will come on.
    Then set the timing To 4 degrees . You can go as high as 8 but i find I get the best combination of performance and gas milage at 4 degrees.
    When yur done timing it reconnect the wire and the check engine light should go out.
     
  6. GRINCH

    GRINCH 1/2 ton status

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    Not doubting you but shouldn't it be 0 degrees? That's what I have been told. I have a 90.
     

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