Bringing TBI and Multi Port Fuel Injection to a New Level.     EFI Conversions and Tuning! Seattle to Portland! E-mail Tuning Consultant!
Results 1 to 9 of 9

Thread: down grading obd2 to obd1

  1. #1
    Fuel Injected!
    Join Date
    Aug 2012
    Posts
    272

    down grading obd2 to obd1

    I live on a small island and have a neigbour with a 98 chev 4x4 in really nice shape. It has a 305 and I think he has cooked the motor which I think started out with a troublesome spider injector. His cost could be quite high having it towed off island to a dealer so wanted to know if I was interested. I have a spare lightly modded big block, 7427 pcms, harnesses and all I need to swap including TP5, apu1 and I know how to use it. I have no interest buying the expensive software to work with 0411. So the question is what do you think. Reasonable or should I just scrap the idea.
    6395, BHDF, 7.4 BBC lightly modded now 6395 BMHM back to BHDF

  2. #2
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    3,406
    There are many options. One challenge is the 1998 transmission, which might not work with the '7427 PCM (unless the 1998 Chevy 4x4 is manual trans).

    dave w

  3. #3
    Fuel Injected!
    Join Date
    Aug 2012
    Posts
    272
    Thanks for the reply. I thought I would be able to just use a OD bin. If the 98 is different enough to not work with OD I guess that will scrap that idea. Running the big block on OD wouldn't be a problem as I have been involved with that before.
    6395, BHDF, 7.4 BBC lightly modded now 6395 BMHM back to BHDF

  4. #4
    Carb and Points!
    Join Date
    Dec 2015
    Age
    54
    Posts
    7
    Hi all,

    Correct me if I am wrong, but isn't the only real difference in the transmission controls the fact that the later tranny uses a PWM lock-up converter?
    My current 1998 Blazer has a 4L60E as did my 1994 Jimmy. The 1994 used a 6395 PCM whereas the 1998 uses a 279 "Black Box" PCM.
    Is there any way to add the PWM code into the older PCM? If so, I am sure that there would be others wanting to make this swap as well!

    Mike.

  5. #5
    Fuel Injected!
    Join Date
    Oct 2013
    Posts
    790
    If you're talking a 4L60e then I'd think a 95 code would work. I believe all 95 4L60e were PWM. The resistances of at least one of the solenoids changed in 96 though so I'm Just not sure how well the transmission would like that. I suppose you could put a 95 PWM valve body into the transmission so it matches the PCM.

  6. #6
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    3,406
    I don't know all the EXACT details about the early one piece 4L60E vs. the later two piece 4L60E. My experience early vs. late 4L60E's has been for using an '0411 PCM on an early 4L60E. Long story short, the early 4L60E can be modified to work with the '0411. It makes sense that the later version 4L60E could "(should)" be modified to work with $OD with the assistance of a "Hot Rod" friendly transmission technician. Most transmission technicians are Not "Hot Rod" friendly.


    dave w
    Last edited by dave w; 1 Week Ago at 12:19 PM.

  7. #7
    Fuel Injected!
    Join Date
    Aug 2012
    Posts
    272
    Turns out the deal didn't work out but I did check the tcc solenoid and they are the same number for 95 and 98 so I think a 95 $OD bin would work in that truck with a 7427 pcm.
    6395, BHDF, 7.4 BBC lightly modded now 6395 BMHM back to BHDF

  8. #8
    Fuel Injected!
    Join Date
    Oct 2013
    Posts
    790
    It's not the TCC solenoid that is different pre 96 vs post 96. I think it might be the 3-2 kickdown solenoid.

  9. #9
    Fuel Injected!
    Join Date
    Aug 2012
    Posts
    272
    Yes you are correct. After I last posted I did some more digging. It appears they not only changed the frequency/resistance but they also changed some routing in the valve body and the 3-2 seems to be the main area of change.
    6395, BHDF, 7.4 BBC lightly modded now 6395 BMHM back to BHDF

Similar Threads

  1. flashing OBD2 ECU?
    By vwnut8392 in forum OBDII Tuning
    Replies: 4
    Last Post: 2 Weeks Ago, 03:43 PM
  2. matching obd2 bin and xdf
    By myburb in forum OBDII Tuning
    Replies: 6
    Last Post: 06-23-2016, 02:57 AM
  3. Replies: 1
    Last Post: 03-01-2015, 03:04 AM
  4. 97 camaro lt1 obd2 to obd1 conversion
    By 71-nova-lt1 in forum GM EFI Systems
    Replies: 16
    Last Post: 01-20-2014, 01:37 PM
  5. Power on 16 pin OBD1 (OBD2 type) connectors
    By phonedawgz in forum GM EFI Systems
    Replies: 1
    Last Post: 12-30-2013, 10:05 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
  •