Page 1 of 2 12 LastLast
Results 1 to 15 of 16

Thread: 250 conversion

  1. #1
    Carb and Points!
    Join Date
    Nov 2013
    Location
    Montague PE , Canada
    Age
    48
    Posts
    7

    250 conversion

    Hello,

    I'm new to Gear Head EFI, and would like to try converting a 250 that's in my old Nova to TBI. I have a 1995 chev half ton with a 4.3 automatic, that i want to use as a donor. I want to use as much of the TBI from the truck as possible, but I don't know just how much feed back the computer needs from the tranny as well as other components. And I'm not sure where to start. Any help or ideas would be appreciated .

    Thanks

  2. #2
    RIP EagleMark's Avatar
    Join Date
    Feb 2011
    Location
    North Idaho
    Age
    63
    Posts
    10,477
    Start by starting!

    Lots of rewiring the harness to get un-needed things out then power fuses etc in. Having a aftermarket VSS is all the PCM needs to be happy. One key piece that is hard to find used but available new is IIRC 1986 six cylinder had a drop in read Large Cap distributor that was EFI ready. Only year available! There are other ways to get the signal and spark control but this is the best.

    There's a start up to get you an idea of what's going to be needed here:
    http://www.gearhead-efi.com/gm-ecm-p...onversion.html
    and here:
    http://www.gearhead-efi.com/Fuel-Inj...Engine!-HOW-TO!

    For the tuning end there's a TunerPro RT article that will help you catch up there too!
    http://www.gearhead-efi.com/Fuel-Inj...-a-must-read!-)

    Keep reading, it'll help you with terminology so we know what your talking about, work on one thing at a time, ask questions when need be.

    And


    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  3. #3
    Carb and Points!
    Join Date
    Nov 2013
    Location
    Montague PE , Canada
    Age
    48
    Posts
    7
    Sorry, I goofed, the donor is a 96. Thanks for the links. I'll definitely check them out! I have a distributor from an 85 4.3 that was carbureted, I wonder if it will work. Thanks again!

  4. #4
    RIP EagleMark's Avatar
    Join Date
    Feb 2011
    Location
    North Idaho
    Age
    63
    Posts
    10,477
    Pretty sure it will not fit. To costly to do the machine hybrid swap when one is available to purchase. There is alsoa way to mount the EST extermanl on aluminum plate, weld up mechanical advance, remove vacuum advance and install a DuraSpark module in distributor to send signal to external EST... lot of work and no where near as good as the available large cap HEI distributor for the six cylinder chevy engine.

    96 PCM is also more costly when it comes to tuning software. Most everything else will work. You may be better off starting with a 95 and older ECM/PCM and harness although that harness could be respliced to pins and plugs for earlier ECM/PCM. Lots more work...

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  5. #5
    Super Moderator Six_Shooter's Avatar
    Join Date
    Feb 2011
    Posts
    2,968
    '96 TBI? I thought the 4.3 were all CPI in '96?
    The man who says something is impossible, is usually interrupted by the man doing it.

  6. #6
    Carb and Points!
    Join Date
    Nov 2013
    Location
    Montague PE , Canada
    Age
    48
    Posts
    7
    It could well be CPI. I know what TBI is, But I'm not sure what CPI is. I was even tossing around the idea of taking the motor and tranny from the truck as well. But the idea of an injected 250 is more interesting.

  7. #7
    RIP EagleMark's Avatar
    Join Date
    Feb 2011
    Location
    North Idaho
    Age
    63
    Posts
    10,477
    Well at first it was a 95, then it was a 96? If you know what TBI is then I'm guessing you have not seen the truck yet? Or you would know...

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  8. #8
    Carb and Points!
    Join Date
    Nov 2013
    Location
    Montague PE , Canada
    Age
    48
    Posts
    7
    Is that 1986 distributor from a 250, or a V6, and is it marine, or a regular motor?
    Thanks

  9. #9
    RIP EagleMark's Avatar
    Join Date
    Feb 2011
    Location
    North Idaho
    Age
    63
    Posts
    10,477
    It's in a car inline six, not sure the CID...

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  10. #10
    Carb and Points!
    Join Date
    Nov 2013
    Location
    Montague PE , Canada
    Age
    48
    Posts
    7
    Oh yes, the truck is here, I goofed on the year, because I was trying to concentrate on typing while holding a squirming baby. I thought it was TBI simply because there was no fuel rails.

  11. #11
    RIP EagleMark's Avatar
    Join Date
    Feb 2011
    Location
    North Idaho
    Age
    63
    Posts
    10,477
    Being CPI it's not going to be a good donor vehicle for your project...

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  12. #12
    Super Moderator Six_Shooter's Avatar
    Join Date
    Feb 2011
    Posts
    2,968
    Quote Originally Posted by EagleMark View Post
    Being CPI it's not going to be a good donor vehicle for your project...
    This is what I was thinking.
    The man who says something is impossible, is usually interrupted by the man doing it.

  13. #13
    RIP EagleMark's Avatar
    Join Date
    Feb 2011
    Location
    North Idaho
    Age
    63
    Posts
    10,477
    Maybe drop the motor and trans in the Nova? Then a good donor!

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  14. #14
    Carb and Points!
    Join Date
    Nov 2013
    Location
    Montague PE , Canada
    Age
    48
    Posts
    7
    Yeah, I'm thinking that's what I'll do. That will give me the benefit of the overdrive autmatic too. Thanks for the help, I'm still interested in using this site, as I still plan on trying to convert one of my other cars to EFI. Thanks again! I will post my progress if any one is interested.

  15. #15
    RIP EagleMark's Avatar
    Join Date
    Feb 2011
    Location
    North Idaho
    Age
    63
    Posts
    10,477
    Heck yeah! Post up a build thread and show us the new power plant. It will make for a nice car!

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

Similar Threads

  1. New here and about to under take a conversion
    By climber8483 in forum Introductions
    Replies: 7
    Last Post: 10-05-2013, 01:13 AM
  2. hello from connecticut with a tpi conversion
    By monte350 in forum Introductions
    Replies: 0
    Last Post: 07-19-2013, 08:16 PM
  3. new efi conversion
    By jester in forum Introductions
    Replies: 5
    Last Post: 03-24-2013, 01:31 AM
  4. My First EFI Conversion
    By EagleMark in forum GM EFI Systems
    Replies: 1
    Last Post: 09-18-2011, 04:00 PM
  5. New here, need some direction on IH EFI conversion.
    By jay harvester in forum GM EFI Systems
    Replies: 5
    Last Post: 04-16-2011, 06:36 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •