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TBI running bad when engine is hot

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by MudFlap, Nov 22, 2004.

  1. MudFlap

    MudFlap 1/2 ton status

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    My buddy has a 4.3 in a 89 S10 and it runs fine when it is cold and when it gets to temperature it runs bad. I remember reading on here about some kind of sensor that can make a tbi do this, like the iac or some kind of temp sensor or something. I tried searching for it but I couldn't find it. Can someone help me?

    Thanks
     
  2. dave_90_blazer

    dave_90_blazer 1/2 ton status

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    probably the ECT(Engine Coolant Temperature) sensor

    it could be other things, if you/he have acess to a scanner, see what the ect reading is when it is warmed up, should be 200 ish


    if no scanner, the sensor should be fairly cheap
     
  3. 87BrnRsd

    87BrnRsd 1/2 ton status

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    Why dont you have him "jump" the a and b pins on the computer hookup under the dash and pull the codes. Thats a surefire way to figure out if something isnt performing properly. My opinion is that it is probably the egr valve. This valve is supposed to open and close and let air into the combustion chamber depending on engine temperature, and if it doesnt, the tbi engine can run like crap when it gets warm. Trust me, my truck did the same thing.
    -Harrison
     
  4. MudFlap

    MudFlap 1/2 ton status

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    Thanks, for the replies. He says that he is gonna sell it and it will be cheap, so I ws thinking about buying it if it could be an easy fix.
     
  5. 87BrnRsd

    87BrnRsd 1/2 ton status

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    Sometimes these TBI motors can do pretty strange things. There are so many "old technology" computers and sensors on them that something is bound to malfunction somewhere. The good part is that parts are a dime a dozen for these motors, and most problems are easy and inexpensive to fix. I say buy the truck. If its a computer problem (which im pretty sure it is) then it should be very easy to deal with.
    -Harrison
     

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