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TBI to carb....

Discussion in 'The Garage' started by SUBFAN, Jul 28, 2004.

  1. SUBFAN

    SUBFAN 1/2 ton status

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    Help me make a list of things to change over.

    For my '90 'Burb....I am contemplating a stroked Pontiac or a 420" sbc. I don't like the idea of chip burning and such. I want to keep it simple and cheap, using parts I have already gathered....

    For you FI lovers, my carbed '77 used to be the one on the block that ran around and jump started all the FI cars....
     
  2. tiger9297

    tiger9297 1/2 ton status

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    I have a '90 K5 and I'm looking to remove stock engine w/ a new one. I have thought about going w/ a carb. but i don't want to have to disable all of the computer junk, as my truck is basically in like new condition. If there is a way to do it I'd love to hear about it. You could just go with a bigger TBI and manifold. You can get a 750 cfm TBI. I think the stock one is 450 cfm. Just a suggestion. I would be very interested to know what you decide.
     
  3. shaun

    shaun 1/2 ton status

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    I am in the process of doing this. I was just going to swap a carb onto my truck but it ends up being not that simple. Once you remove the injectors (throttle body) you have to run a power sw to your pump (or wire it to your ignition). Then you have to put in a pressure regulator. I assume you would eliminate the ecm which I was. This will eliminate the ICM which means no power to the coil so no spark. Meaning you will have to swap in a new distributor, coil and do some wiring or simply run voltage to your present coil. These were just some of the things to do.

    So I said f it and am ripping out my tbi 350 and wiring harness complete. I am putting in the gm 18 circuit painless wiring kit with a carbed 402 and will use that until I can afford marine fuel injection for the 402.
     
  4. SUBFAN

    SUBFAN 1/2 ton status

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    Since I am not big on wiring, the elimination of as many as possible would be sweet. All that crap just burns my a$$ being in the way.

    biggest reasons for thinking about switching back, is simplicity and cost involved with getting more air fuel into it, not even counting the chip /forums/images/graemlins/thinking.gif
     
  5. SUBFAN

    SUBFAN 1/2 ton status

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    Does the computer need to 'see' oil pressure? '90 TBI motor....
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    It needs it for the fuel pump wiring, thats it. (if the fuel pump relay fails, once the oil pressure switch sees approx. 5 psi, it will turn the pump on)

    I thought a '90 would already be setup this way, but around that vintage cars and trucks went to a combination pressure switch/sender that is smaller than the earlier truck oil pressure sender. Run all three wires to the same one. Much cleaner IMO.
     
  7. shaun

    shaun 1/2 ton status

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    If the computer does not see oil pressure it will cut the signal to the fuel pump. This is a safety feature to prevent you from blowing your engine by running it with no fuel. I am pretty sure that is how it works.
     
  8. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    [ QUOTE ]
    If the computer does not see oil pressure it will cut the signal to the fuel pump. This is a safety feature to prevent you from blowing your engine by running it with no fuel. I am pretty sure that is how it works.

    [/ QUOTE ]

    that is why when I put a 1991 caprice police motor in my truck I went from TBI to Carb.. I like my truck so stupid... /forums/images/graemlins/waytogo.gif
     
  9. SUBFAN

    SUBFAN 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    If the computer does not see oil pressure it will cut the signal to the fuel pump. This is a safety feature to prevent you from blowing your engine by running it with no fuel. I am pretty sure that is how it works.

    [/ QUOTE ]

    that is why when I put a 1991 caprice police motor in my truck I went from TBI to Carb.. I like my truck so stupid... /forums/images/graemlins/waytogo.gif

    [/ QUOTE ]



    EXACTLY..... /forums/images/graemlins/waytogo.gif /forums/images/graemlins/bow.gif /forums/images/graemlins/waytogo.gif /forums/images/graemlins/thinking.gif
     

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