Results 1 to 11 of 11

Thread: GM TBI conversion on a 304 CJ-7

  1. #1
    Electronic Ignition! Texasdave's Avatar
    Join Date
    Feb 2016
    Location
    Killeen, TX
    Age
    73
    Posts
    11

    GM TBI conversion on a 304 CJ-7

    Went to the Junkyard yesterday and pulled what I hope is everything I need to do this conversion. The donor vehicle was 1989 Sierra GMC pickup. The ECM was an 1227747. The BCC is still to be determined. I did not see any where I thought they should be. However on the ECM with all the information it had ASKF. I believe that is the BCC ID. I'll have to check when I get home to confirm the order of the letters. When I did a BIN search those letters did not come up. Anyone know anything about this chip? I will be going through this step by using the information found on this site. The help here has been tremendous especially david w and Eaglemark. I will keep you posted as to my progress from time to time and seek advice. I am putting it on a 304 AMC bored to .30 over. I will check with the fellow that redid it to find the cam he used.

  2. #2
    Electronic Ignition! Texasdave's Avatar
    Join Date
    Feb 2016
    Location
    Killeen, TX
    Age
    73
    Posts
    11
    Okay, basic question. My Jeep did not come with a check engine light so when I'm wiring in the TBI conversion do I need to wire in some sort of light?

  3. #3
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,247
    Yes.

    The computer will supply the "Ground" to the check engine light when there is an error. The other wire of the light is connected to the ignition switch ("On").

    dave w

  4. #4
    Electronic Ignition! Texasdave's Avatar
    Join Date
    Feb 2016
    Location
    Killeen, TX
    Age
    73
    Posts
    11
    Working on the wiring harness and and I am unsure of which wires I need and which I don't. I have two multi-port plugs in the wiring bundle that connects to the wiring bundle inside the vehicle (1990 Chevy Pick up donor vehicle). DO I cut these out? I think I should but I'm unsure what they connected to inside the cab. I feel like a bomb tech do I cut the pink wire or do I cut the green/black wire. Only good thing, at least I won't blow myself up.
    Last edited by Texasdave; 03-22-2016 at 07:24 PM.

  5. #5
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,247
    Figure out the ECM wiring first, here is a link to the 1227747 wiring schematics: http://www.gearhead-efi.com/Fuel-Inj...Information-42

    dave w

  6. #6
    Electronic Ignition! Texasdave's Avatar
    Join Date
    Feb 2016
    Location
    Killeen, TX
    Age
    73
    Posts
    11
    When I removed the wiring harness it had a bulkhead connector, or at least I thought it was. In reality the wires go straight through and are covered by this plastic goop. I heated the goop and it melted allowing me to separate the wires. This makes it easier to work with them. BTW I was careful not to get it so hot that it melted the wire coating.

  7. #7
    Fuel Injected!
    Join Date
    Jul 2012
    Location
    Fresno, CA
    Posts
    422
    Quote Originally Posted by Texasdave View Post
    When I removed the wiring harness it had a bulkhead connector, or at least I thought it was. In reality the wires go straight through and are covered by this plastic goop. I heated the goop and it melted allowing me to separate the wires. This makes it easier to work with them. BTW I was careful not to get it so hot that it melted the wire coating.
    Yep, that's the fun part!
    1973 K-5 Blazer, TBI 350, TH400, 1 ton axles & 38" SSRs'
    1975 280Z, TBI 350, 700R4
    1953 M-38A1, TBI Buick 231
    1951 Ford Panel, 5.3 with 4L80E

  8. #8
    Electronic Ignition! Texasdave's Avatar
    Join Date
    Feb 2016
    Location
    Killeen, TX
    Age
    73
    Posts
    11
    Because I cut the wires short to the ALDL I am going to have to add some wire to be able to mount it. What is the preferred method? Soldering and shrink wrap or unpinning from connector and crimping new wire?

  9. #9
    Fuel Injected!
    Join Date
    Jul 2015
    Location
    Belton, Tx
    Age
    49
    Posts
    91
    hey your in my neck of the woods:)

    I'm not at expert at ECMs and programming, but I have worked in wiring a couple years now. When these guys mention re-pinning you usually see it when upgrading to a new style of ECM. They are basically moving the wires around to the corresponding pins for that ECM. Some may re-pin for looks. Some may simply wack and soldier the wires where they need to be. The only time I can see actually having to "re-pin" is if you may some how degrade the quality of the circuit. I know that some wire pairs are twisted and some wires have to be shielded. I'm not sure how I would handle those if I came across one that I needed to cut.

    In my case, I'm doing a direct swap. I cut my entire wiring harness from the doner and all my wires are soldiered and shrink wrapped for the ECM.

    Heath
    Last edited by lakedrifter; 04-21-2016 at 06:32 PM.
    lakedrifter

  10. #10
    Electronic Ignition! Texasdave's Avatar
    Join Date
    Feb 2016
    Location
    Killeen, TX
    Age
    73
    Posts
    11
    Okay after some thought and consideration of time and quality I am leaning towards buying a pre-made wiring harness. I was talking with a sales person and he voiced concerns about tuning with a performance cam. Something about trouble with the vacuum values changing and the engine wouldn't idle correctly. Couple of questions: 1) Is this really a problem 2) Can you program the ECM to compensate for this anomaly?

  11. #11
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,247
    Quote Originally Posted by Texasdave View Post
    1) Is this really a problem?
    Yes, depending on the camshaft. Usually "Computer" friendly cams are a good option. Computer friendly Does Not mean "Stock Chip" friendly!

    Quote Originally Posted by Texasdave View Post
    2) Can you program the ECM to compensate for this anomaly?
    Yes, the fuel table (Volumetric Efficiency - VE Table) needs changes based on information from a TunerPro RT data log.

    dave w

Similar Threads

  1. TBI conversion.
    By scottsrc in forum Introductions
    Replies: 5
    Last Post: 01-23-2015, 09:37 PM
  2. 24X LT1 Conversion
    By MYLTWON in forum OBDII Tuning
    Replies: 0
    Last Post: 12-28-2014, 06:32 PM
  3. 4A-GZE conversion
    By ericjon262 in forum GM EFI Systems
    Replies: 16
    Last Post: 11-24-2014, 05:37 AM
  4. s-10 283 tbi conversion
    By hammertime371 in forum GM EFI Systems
    Replies: 30
    Last Post: 09-15-2014, 06:26 AM
  5. new efi conversion
    By jester in forum Introductions
    Replies: 5
    Last Post: 03-24-2013, 01:31 AM

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
  •