Page 3 of 5 FirstFirst 12345 LastLast
Results 21 to 30 of 46

Thread: Seeking Advice on tuning a heavily modified 4L60E

  1. #21
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    Engine bog during shift:

    log SHIFTLAST and see what shift time it reports when engine bogs...

    if logged shift times are 0.2s (same as in tune) then look at wideband during shift, does it momentarily jump lean or rich...?

    also, are VE/MAF tables correct...? (these being correct has another importance also, the PCM computes running line pressure from these).

  2. #22
    Lifetime Member darcy's Avatar
    Join Date
    Feb 2012
    Posts
    223

    Default

    The TM can feel like a bog/hesitation mid-change, as it pulls out timing, to me.
    Have a look in the log and see if there is a huge downspike in timing.

  3. #23
    Lifetime Member HellKnightHicks's Avatar
    Join Date
    Mar 2011
    Posts
    268

    Default

    Quote Originally Posted by joecar View Post
    Engine bog during shift:

    log SHIFTLAST and see what shift time it reports when engine bogs...

    if logged shift times are 0.2s (same as in tune) then look at wideband during shift, does it momentarily jump lean or rich...?

    also, are VE/MAF tables correct...? (these being correct has another importance also, the PCM computes running line pressure from these).

    Im sure my MAF is not correct... Havent even messed with that yet... VE should be close. Thats prolly where the problem is...

    Also when i gun it from about 30 mph It back fires then hauls... Prolly VE or MAF as well

    MAF is still failed by the way.

  4. #24
    Lifetime Member HellKnightHicks's Avatar
    Join Date
    Mar 2011
    Posts
    268

    Default

    Ill try to figure out the SHIFTLAST logging


    Ive been warned not to log to many pids at the same time.

    How do you watch pids as your logging them?

    Will the PID table show that.

    Sorry to show my newbness lol

  5. #25
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    With the LS1B PCM you can log upto 24 pid channels (see bottom of PIDs tab) at 10 frames/second... more than 24 pid channels will reduce the frame speed (5 F/s or less).

  6. #26
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    Log SHIFTLAST, SPARKADV, and wideband...

    then look at SHIFTLAST (does it match the shift time in the tune...?) and look at SPARKADV (what does it drop to...?)

    usually the drop in spark advance does not cause the engine to bog (stock tune has a lot of TR and a long shift time)

    also look at the wideband AFR/Lambda, what does it do during the shift...?

    so basically I think it's due to fueling... $0.02.

    post some log files


    lol, we were all newbies at some time or other, and with all the new stuff coming we're still newbies

  7. #27
    Lifetime Member HellKnightHicks's Avatar
    Join Date
    Mar 2011
    Posts
    268

    Default

    Quote Originally Posted by joecar View Post
    Log SHIFTLAST, SPARKADV, and wideband...

    then look at SHIFTLAST (does it match the shift time in the tune...?) and look at SPARKADV (what does it drop to...?)

    usually the drop in spark advance does not cause the engine to bog (stock tune has a lot of TR and a long shift time)

    also look at the wideband AFR/Lambda, what does it do during the shift...?

    so basically I think it's due to fueling... $0.02.

    post some log files


    lol, we were all newbies at some time or other, and with all the new stuff coming we're still newbies

    Can do thanks

  8. #28
    Lifetime Member HellKnightHicks's Avatar
    Join Date
    Mar 2011
    Posts
    268

    Default

    The previously posted tune contains the transmission section.

    From the looks of it the VE is still a little out of whack.. so that may be the cause of the issue.

    Shift times are not as desired as per watching the Last shift log in the data tab.

    1->2 shift as desired
    2->3 shift was .6 once
    3->4 I think was right.

    Im posting a couple of videos up to youtube so that i can show you or let you hear the engine bog on the 2->3 gear shift under light throttle.

    Log file from my test drive tongiht.Log_0007.efi

  9. #29
    Lifetime Member HellKnightHicks's Avatar
    Join Date
    Mar 2011
    Posts
    268

    Default

    Went for another run tonight.... Feels like ive got alot more tuning to do to get this thing running like it should. But at least it does run.

    Engine starts strong then falls off about 3200 then picks up strong again about 4500 its really odd...

    any way enough talk heres the vid so you can get the idea.


  10. #30
    Lifetime Member HellKnightHicks's Avatar
    Join Date
    Mar 2011
    Posts
    268

    Default

    You can here it bog down there on the 2->3 shift.

    It sounds much better in person... the mic is getting hummed due to the resonance.


Page 3 of 5 FirstFirst 12345 LastLast

Similar Threads

  1. Replies: 0
    Last Post: August 21st, 2012, 03:33 PM
  2. Tuning 02 Suburban 5.3 advice
    By ScarabEpic22 in forum Gen III V8 Specific
    Replies: 23
    Last Post: April 28th, 2011, 04:15 PM
  3. Tuning stock 4L60E
    By caver in forum 4speed RWD/FWD Transmission Tuning (incl T42)
    Replies: 3
    Last Post: October 26th, 2007, 05:54 PM
  4. Tuning a 4l60e
    By B A Barakus in forum 4speed RWD/FWD Transmission Tuning (incl T42)
    Replies: 6
    Last Post: September 26th, 2007, 01:21 PM
  5. Basic FAQ/Tuning Advice
    By mmorgan24 in forum General (Petrol, Gas, Ethanol)
    Replies: 9
    Last Post: April 13th, 2006, 02:49 PM

Posting Permissions

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