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replacing carb with tbi

Discussion in 'The Garage' started by big_black_blazer, Jan 22, 2006.

  1. big_black_blazer

    big_black_blazer 1/2 ton status

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    i'm putting my tbi motor out of my parts truck into my 54 chevy. does anybody know how much of the wiring harness i will actually need to keep from the tbi truck? if anybody else has done this i would appreciate any advice you can give me.
    thanks
    evan
     
  2. big_black_blazer

    big_black_blazer 1/2 ton status

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    surely somebody here knows something about this. i know it's not a blazer, but at least it's a bowtie... c'mon, somebody!
     
  3. Mastiff

    Mastiff 1/2 ton status Premium Member

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    Isn't the TBI harness a separate deal? You'd need everything connected to the TBI computer, which would include power, some relays, and all the sensors on the engine.

    Maybe you could get the manual for the part truck year and see the wiring schematic associated with the TBI. You could also buy a harness from painless and then just harvest the parts you need.
     
  4. 1979jimmy350

    1979jimmy350 1/2 ton status

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    If you have every thing from the other truck it should be pretty easy if you have a wiring manual for the TBI which should be easy to get. You could go about it two way really. You could set up the harness to piggy back on the orignal harness or you could take the entire harness from the TBI truck if you have it and adapt that to your truck. The second option gives a few advantages. You get to upgrade to the new blade style fuses and more fuse cability so you can run other assories to the fuse block. This option is rater involved though i am curently doing this myself for a older blazer with a newet TBI harness repined to TPI and there is a lot of sodering and wire tracing to do
     
  5. LucasJ03

    LucasJ03 1/2 ton status

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    I put one in my 72 K5 and I would strongly recommend a painless wiring harness. I tried to go through a stock harness but had no lucI got a painless and had it started in 40 minutes. The downside they are around $400 bucks .
     
  6. 1979jimmy350

    1979jimmy350 1/2 ton status

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    i would say go painless if you have the money the only reason i did not was i had the harness around and i am a poor college student and 400 buys a lot of beer:)
     
  7. eagle mark

    eagle mark 1/2 ton status

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    $400. ??? :eek1:

    How about $225. ? and a CK5 discount... :pimp:
    http://www.affordable-fuel-injection.com/tbi-wiring-harness.htm
     
  8. divorced

    divorced 3/4 ton status

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  9. mouse

    mouse 1/2 ton status

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    While the after market harnesses are definitely nice and easy to use, the stock GM harness was engineered for many years of service. If you have just the bare minimum of wiring skills - can solder, wire-tie, and crimp connections, I would attempt to use the donor harness. Of course if the harness has been damaged or hacked by someone, then maybe not.

    I completed the carb to TBI swap last week using the harness from the donor truck. Three circuits going through the fuse block connection at the firewall were resoldered into the existing harness, otherwise the entire engine harness was used. There is also a small under dash harness that I used for the VSS and ALDL. While I was wiring I added a painless add-on fuse block to clean up under the dash and provide some extra sources of power.

    Heres a couple of sites to visit:
    http://www.speedyoldtruck.com/index.php?page=tbiretrofit
    http://www.justinternationals.org/international-fuel-injection.htm
    http://www.thirdgen.org/
     
  10. eagle mark

    eagle mark 1/2 ton status

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  11. big_black_blazer

    big_black_blazer 1/2 ton status

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    what's the chance of being able to start at each sensor and trace back to the harness's connector, and just keep the sensors and the power supply to the computer? i already have the truck (not donor) wired and running w/ a carbed 305, and just want the bare essentials to run w/ tbi. not even the electric fuel pump.
     
  12. 1979jimmy350

    1979jimmy350 1/2 ton status

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    you will need a electric fuel pump to run the TBI. There are some things that you jsut to have to run the TBI. Your best bet is to get a factory service manual then for the wiring digrams and start figuring out how you can wire it up to have the min of wires
     
  13. mouse

    mouse 1/2 ton status

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    I found all of the wiring diagrams here and elsewhere on the internet. It just took a little searching...plus its free.
     

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