Results 1 to 4 of 4

Thread: Integrator/BLM not working correctly

  1. #1
    Fuel Injected!
    Join Date
    Apr 2020
    Age
    32
    Posts
    32

    Integrator/BLM not working correctly

    Back to tuning on my POS 95 Sierra after letting it sit for a while out of sheer frustration. It's a 355 running 9.5:1 compression with a stock lt4 cam. Has a factory 5.7 tbi unit bored out to 50mm and horns shaved off with new factory spec 5.7 injectors with fuel pressure bumped up to 18psi and 30 psi big block fuel pump in the tank. Edelbrock performer intake with summit vortec heads and shorty headers. I've used Trimalyzer in open loop and gotten the AFR error to less than 5%. After switching back to closed loop I immediately found the Integrator and BLM will peg rich yet the o2 is pegged lean (verified with Tunerpro data and physically tapping into the signal at the ECM) and the truck runs like crap and the wideband is pegged lean also. I've done some reading and see this may be the o2 switching points? What can I adjust to fix this? I swear if I had known this would be this much of a pain I would have just done a stock rebuild. Thanks for any help, I've been tuning this thing off and on forever and am about ready to throw in the towel.
    Last edited by 95GMC; 07-12-2022 at 05:22 PM.

  2. #2
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,302
    Maybe post a WBO2 TunerPro RT Datalog?

    dave w

    Near Idle.jpg

    Off Idle.jpg

    Spark Advance.JPG

  3. #3
    Fuel Injected!
    Join Date
    Jan 2021
    Location
    Deep in the heart of Texas
    Posts
    73
    Interestingly enough I read a thread with a very similar situation and it turned out to be his NB O2 sensor.
    Just a thought.

  4. #4
    Fuel Injected!
    Join Date
    Apr 2020
    Age
    32
    Posts
    32
    I will try to get a datalog posted, it may be a bit as I need the truck at the moment and it's completely undriveable in closed loop so I'll have to make a special drive on a back road where I can limp along and datalog. I noticed also the really big driving factor in pulling too much fuel is the BLM. If I disable it and just run off the integrator the fuel control is actually pretty decent. Also it is not the narrow band o2 as it's a new denso unit and it bench tests correctly and corresponds to my wideband o2 readings and switches well when the ECU is controlling the fueling properly.

Similar Threads

  1. Replies: 2
    Last Post: 01-04-2019, 06:18 PM
  2. Replies: 9
    Last Post: 06-17-2017, 06:04 PM
  3. IAC not functioning correctly
    By Chewy1576 in forum GM EFI Systems
    Replies: 12
    Last Post: 03-22-2015, 08:10 PM
  4. Headers/integrator delay
    By dyeager535 in forum GM EFI Systems
    Replies: 6
    Last Post: 02-18-2013, 08:50 AM
  5. Can not get PCM bins to display correctly
    By JeepsAndGuns in forum GM EFI Systems
    Replies: 32
    Last Post: 09-20-2011, 02:45 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
  •