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Thread: TBI 4.3 to TBI Vortec 4.3 Whats needed?

  1. #31
    Insane Network Engineer rlith's Avatar
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    Ok....let me make a few clarifications for people...

    Difference between blocks... the CPI motor uses a bigger cam and freer flowing heads. Bolt patterns are all the same for the heads all the way to 95, they changed in 96.

    A TBI intake will fit fine on a CPI block with the CPI heads.

    To convert TBI to CPI you will need obviously the intake, CPI unit, Engine Harness, ECM, Fuel pump (CPI runs at 60-65 while TBI runs 9-12) and modified fuel lines.
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  2. #32
    Round 300k & Still Kick'N
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    so im hearing 2 different things then, that this is a CPI engine and it needs alot of stuff to make it run right and that its a tbi engine with vortec heads and it only needs a computer. so which is it? CPI vortec or TBI vortec, it sure looks like my regular TBI 4.3L and its from a first Gen thats a 94?
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  3. #33
    DRO LIFE dropped88blazer's Avatar
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    Your motor is not a CPI. Everyone is kinda just goin over the differences between the 2 Vortecs it seems. Basically you have the much easier of the 2 to swap into your truck.

  4. #34
    Senior Member RMassa187's Avatar
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    CPI and TBI refers to the way the fuel is injected into the motor. Central Port Injection and Throtle Body Injection. The blocks are the same. CPI is a manifold type. TBI is a manifold type.

  5. #35
    Insane Network Engineer rlith's Avatar
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    Originally posted by RMassa187
    CPI and TBI refers to the way the fuel is injected into the motor. Central Port Injection and Throtle Body Injection. The blocks are the same. CPI is a manifold type. TBI is a manifold type.
    Stock TBI blocks are the same except for the cam..
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    95 S10 Blazer 4x4, Vortech CPI, EGR mod, 99 Centerconsole w/ shifter, , 2001 Extreme zq8 steering box, Pioneer head unit, Leather interior

    -- I won't bag it and/or drop it, because face it, I'm too old to have a ghetto-mobile
    "I live with 2 retards and a deaf person.....It's not so bad..." --Grandma

  6. #36
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    hahaha lol I know what TBI means and what CPI means and i know the 4.3L blocks are all the same, all I want to know is if this swap will require more work than I think or not. I have got a couple responses from RMassa187 and someone else saying it would easy thing that gets me is I keep getting these its gonna take a new fuel pump wireing harness ect. ect. and I think they are talking about if i was converting to CPI which im not. I looked in the Hanes manual and saw that 94's had a Knock sensor on the pass. side of the block and Rear of the block on the drivers side and 93's didnt and thats all i could find lookin through the book that was different, But Mine has the Knock Sensors in the same Place cuz I replaced them so it probly has the same engine as a 94 so it was probly produced later in 93. I think it sayd 93 and below had 1 or no Knock sensors and i know for sure I have 2 because I replaced 2. I looked under Emission to find this information in the book, is there anywhere else i should look? i looked in the Wireing diagrams in the back and could only find one and it sayd 4.3L v6 so that must include the vortec engines. oh and by the way thank yall for helping me out, now If i could get some clearer answers on wether this will work or not and not about if a CPI will work that would really help.
    Black 1993 GMC Jimmy (4.3L)Flowmaster Exhaust, Heddman Hedders, Custom Intake, K&N FilterCharger Dats Really about it.

  7. #37
    Insane Network Engineer rlith's Avatar
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    Lets make it more simple since you're going from TBI to TBi...

    If you're getting a 95 and below TBI motor, then all you need to do is swap your intake to the new motor and drop it in... If you're getting a later model CSFI motor (96 and up) then you need to swap the HEADS and intake from the TBI as the manifold bolt patterns are different (unless you want to redrill the newer style heads to fit the older TBI intake. Doable but a lot of work and money. Easier to swap the heads over with the intake. You will also need to swap over the distributor and NOT hook up the crank sensor (since it wasn't in use on yours, it can stay dead) If you only had 1 knock sensor, remove the extra knock sensor on the newer motor and just use a plug (pull one of the old plugs off the old motor)....
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    95 S10 Blazer 4x4, Vortech CPI, EGR mod, 99 Centerconsole w/ shifter, , 2001 Extreme zq8 steering box, Pioneer head unit, Leather interior

    -- I won't bag it and/or drop it, because face it, I'm too old to have a ghetto-mobile
    "I live with 2 retards and a deaf person.....It's not so bad..." --Grandma

  8. #38
    Senior Member RMassa187's Avatar
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    How has this gotten so complex????? Just swap the motors. They are exactly the same. Throw that hanes manual out. They lump all the info for the years together and omit the important stuff. You won't find all the design changes.

    These are the same motors. If the harness has plugs for two knock sensors then plug them in. If it has one then plug that one in.

  9. #39
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    if you look over the whole post it is complex, what im talking about is Swaping a 94 vortec TBI 4.3L V6 in my 93 that had a TBI 4.3L V6. Im not talking about Swapping it for a newer model CPI 4.3L V6 out of a newer model car and there is alot of talk about this motor when its not even what Im Swaping. I found a Deal on a 94 Vortec engine and have no plans on buying an engine newer than that. Thats why its getting confusing cuz im getting all these its easy and then its not worth it answers so I sayd keep it TBI vortec instead of CPI vortec.
    Black 1993 GMC Jimmy (4.3L)Flowmaster Exhaust, Heddman Hedders, Custom Intake, K&N FilterCharger Dats Really about it.

  10. #40
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    wow this is alot of good info now im thinking about getting a 96 or newer engine for my 1994 blazzer but will I need a new computer/wireing harness?
    Good luck on your engine swapshould go smoothe hopefully.

  11. #41
    Insane Network Engineer rlith's Avatar
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    Originally posted by kenrhodes
    wow this is alot of good info now im thinking about getting a 96 or newer engine for my 1994 blazzer but will I need a new computer/wireing harness?
    Good luck on your engine swapshould go smoothe hopefully.
    Wow, this thread is a year old...(don't ressurect old threads!)

    That said, yes, you would need the 96+ ecm and engine harness as well as a lot of rewiring for your dash and accessory controls.
    Support Sattelite Radio! Goto www.siriusbackstage.com
    goto http://www.pghconsulting.net/teal to see my updated pics!
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    95 S10 Blazer 4x4, Vortech CPI, EGR mod, 99 Centerconsole w/ shifter, , 2001 Extreme zq8 steering box, Pioneer head unit, Leather interior

    -- I won't bag it and/or drop it, because face it, I'm too old to have a ghetto-mobile
    "I live with 2 retards and a deaf person.....It's not so bad..." --Grandma

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