Page 2 of 5 FirstFirst 12345 LastLast
Results 16 to 30 of 63

Thread: 94 F-body LT1 solving problems/tune

  1. #16
    Fuel Injected!
    Join Date
    Sep 2014
    Location
    -(718)-
    Age
    49
    Posts
    205
    5. DISABLE AIRpump
    Besides clicking OFF at least two switches / flags, you must ALSO raise the Min Coolant Temp to Enable AIRpump to well over 117.5°C / 243.5°F.

    Generally speaking, if you want to disable anything, you often need to take more than one step, possibly two or three or more to do so.

    To wit:
    1. I think Catalytic Protection can be disabled with only one constant, but just in case, I'd adjust four, as GM did.
    THEY are NOT Lying to You.
    You are NOT Even Lying to Yourself.
    You ARE Being Lied to ... by Your SELF.
    The Last Psychiatrist, aka ... Alone ...


  2. #17
    Fuel Injected!
    Join Date
    Apr 2020
    Location
    Belarus
    Age
    35
    Posts
    152
    AIR pump done.

    Regarding CAT protection
    Factory Cat protect AFR is 12.2. Is it bad for the whole engine cooling? And what about torque? I know that it raises a little when it goes to rich. Just about 11.8-12.8

    There are Low/High boundaries and Low/Mid/High Pressure parameter. Should i mod them and to what values?

    Is it good idea to disable cat protection? Or it's good to leave it alone? If only I'm right in everything that I said above.
    I remind that I've deleted CAT.
    Last edited by yoheer; 06-27-2020 at 10:39 AM.

  3. #18
    LT1 specialist steveo's Avatar
    Join Date
    Aug 2013
    Posts
    4,008
    i honestly don't see much point in cat protect mode even with a cat, but if you have no cat, there's definitely no reason to leave it enabled

  4. #19
    Fuel Injected!
    Join Date
    Sep 2014
    Location
    -(718)-
    Age
    49
    Posts
    205
    Quote Originally Posted by yoheer View Post
    Regarding CAT protection
    Factory Cat protect AFR is 12.2. Is it bad for the whole engine cooling? And what about torque? I know that it raises a little when it goes to rich.
    Just about 11.8-12.8

    There are Low/High boundaries and Low/Mid/High Pressure parameter. Should i mod them and to what values?

    Is it good idea to disable cat protection? Or it's good to leave it alone? If only I'm right in everything that I said above.
    I remind that I've deleted CAT.
    GM uses the following values for vehicles that were never equipped with catalytic converters:

    Min Coolant Temp for CAT Protect = 150°C
    CAT OverTemp Threshold (Low Baro) = 1065°C
    CAT OverTemp Threshold (Mid Baro) = 1065°C
    CAT OverTemp Threshold (High Baro) = 1065°C
    CAT OverTemp Air Fuel Ratio = 12.2 AFR

    (Although I'd raise the CAT OverTemp Air Fuel Ratio to 14.7 AFR without any fear.)
    THEY are NOT Lying to You.
    You are NOT Even Lying to Yourself.
    You ARE Being Lied to ... by Your SELF.
    The Last Psychiatrist, aka ... Alone ...


  5. #20
    Fuel Injected!
    Join Date
    Apr 2020
    Location
    Belarus
    Age
    35
    Posts
    152
    you convinced me guyz )))
    Want to know your thoughts about egr and BLM locker.

    After all Im gonna mod timing, AFR and everything to make the engine more responsible and add some HP.
    I will need advices.
    Last edited by yoheer; 06-28-2020 at 02:43 PM.

  6. #21
    Fuel Injected!
    Join Date
    Apr 2020
    Location
    Belarus
    Age
    35
    Posts
    152
    Disabled EGR

  7. #22
    Fuel Injected!
    Join Date
    Apr 2020
    Location
    Belarus
    Age
    35
    Posts
    152
    Should i mod smth about deleted cat?
    I'm running ~93 octane.
    And 160 t-stat and fan temps are lowered (operating temp ~195)
    What tables should I pay attention to?

  8. #23
    Fuel Injected!
    Join Date
    Sep 2014
    Location
    -(718)-
    Age
    49
    Posts
    205
    Quote Originally Posted by yoheer View Post
    Should i mod smth about deleted cat?
    You can raise the 'CAT Protect Min Coolant Temp'. Anything over 120°C should do fine.
    THEY are NOT Lying to You.
    You are NOT Even Lying to Yourself.
    You ARE Being Lied to ... by Your SELF.
    The Last Psychiatrist, aka ... Alone ...


  9. #24
    Fuel Injected!
    Join Date
    Sep 2014
    Location
    -(718)-
    Age
    49
    Posts
    205
    Quote Originally Posted by yoheer View Post
    Disabled EGR
    Technically, disabling & deleting the EGR Valve are two slightly different things.
    To disable the EGR Valve in the .bin:
    Raise BOTH EGR Enable Coolant Temp Thresholds over 120°C / 248°F in C.A.T.S. OBD1 LT1
    Raise the EGR Enable Min MAP Threshold over 103KPa
    Raise the EGR Enable Min RpM to 5925RpM or the RpM your LT1 engine will never hit, +25RpM)
    Raise the EGR Enable Max RpM to 5900RpM or the RpM your LT1 engine will never hit, which also should be under the EGR Enable Min RpM

    To physically DELETE the EGR Valve properly, use a blockoff plate for best results.
    THEY are NOT Lying to You.
    You are NOT Even Lying to Yourself.
    You ARE Being Lied to ... by Your SELF.
    The Last Psychiatrist, aka ... Alone ...


  10. #25
    Fuel Injected!
    Join Date
    Apr 2020
    Location
    Belarus
    Age
    35
    Posts
    152
    What about fuel tables? It should be leaned a little when the egr if opened. In stock

  11. #26
    Fuel Injected!
    Join Date
    Nov 2017
    Location
    Californiacation
    Age
    57
    Posts
    811
    Yes, I'm not sure LT1's ever had an EGR circuit that was active, however, all other ecm's have quite a few separate "tables" when the EGR is active. Or I should say, when the ecm thinks the egr is active.

    I read all the time where people block their egr and wonder why they have a part throttle lean and knock issue. IF THE COMPUTER THINKS THE EGR IS OPEN IT PULLS FUEL AND ADDS TIMING!!! These are tuneable events and corrections. Changing a cam/exhaust/heads etc drastically alters the egr qualities.

    Some egr's are basically on or off, other later ones are pulse width modulated and there are even more fuel tables and spark tables to work with that.
    Last edited by In-Tech; 08-26-2021 at 12:34 PM.
    -Carl

  12. #27
    Fuel Injected!
    Join Date
    Apr 2020
    Location
    Belarus
    Age
    35
    Posts
    152
    I've found only timing corrections due egr is opened. But can't find where the condition is leaner with egr engaged. Hit me to that table please.

    Also should I correct o2 swing table with cat removed?
    Mine o2 swing table is default. I tried to raise the values in this table to get some power in closed loop, but it seems the car accelerates even harder.

    How far should I move timing with 93 octane?

  13. #28
    Fuel Injected!
    Join Date
    Nov 2017
    Location
    Californiacation
    Age
    57
    Posts
    811
    Are you using the EGR circuit?
    I haven't followed this thread closely, can you post the stock .bin you started with so I can find stuff? Most stuff I have seen can usually accept 5 more degrees of timing on a stock timing table if the engine is stock. If much has been changed you have to tune accordingly. Hopefully more experienced LT1 guys can chime in with how much is acceptable, shoot, they have a pretty aggressive timing table from the factory due to the reverse cooling so I creep up on it and do a lot of logging.
    -Carl

  14. #29
    Fuel Injected!
    Join Date
    Apr 2020
    Location
    Belarus
    Age
    35
    Posts
    152
    Quote Originally Posted by In-Tech View Post
    Are you using the EGR circuit?
    I haven't followed this thread closely, can you post the stock .bin you started with so I can find stuff? Most stuff I have seen can usually accept 5 more degrees of timing on a stock timing table if the engine is stock. If much has been changed you have to tune accordingly. Hopefully more experienced LT1 guys can chime in with how much is acceptable, shoot, they have a pretty aggressive timing table from the factory due to the reverse cooling so I creep up on it and do a lot of logging.
    The stock is in the very first message of this thread. Mod list is there too.
    I've disabled egr, but hadn't removed it manually. It is installed, but not working because of PCM.

  15. #30
    Fuel Injected!
    Join Date
    Sep 2014
    Location
    -(718)-
    Age
    49
    Posts
    205
    Quote Originally Posted by yoheer View Post
    The stock is in the very first message of this thread. Mod list is there too.
    I've disabled egr, but hadn't removed it manually. It is installed, but not working because of PCM.
    Whether you are using MAF Sensor or Speed Density, if you've disabled the EGR Valve operation in the pcm, then it will not apply the EGR spark timing table modifiers.
    O2 sensors take care of the rest, provided they are working well.

    In the long run, your intake manifold will appreciate that you installed an EGR blockoff plate.

    Until you've personally calibrated your spark & fuel tables so that your LTFTs are all between 123 & 133 (123 is slightly better), leave the O2 sensors working.
    THEY are NOT Lying to You.
    You are NOT Even Lying to Yourself.
    You ARE Being Lied to ... by Your SELF.
    The Last Psychiatrist, aka ... Alone ...


Similar Threads

  1. Replies: 73
    Last Post: 05-29-2023, 06:14 PM
  2. OEM Tune - 97 LT1 f Body
    By OhNoItsGodzilla in forum OBDII Tuning
    Replies: 1
    Last Post: 09-17-2019, 05:45 AM
  3. 95 F-body Fuel Pump with 95 B-Body Engine/Tank
    By EPS3 in forum GM EFI Systems
    Replies: 7
    Last Post: 09-19-2016, 02:40 PM
  4. Need help solving surging deceleration and idle
    By Chewy1576 in forum GM EFI Systems
    Replies: 25
    Last Post: 02-21-2016, 03:17 AM
  5. Problems getting my tune down.
    By jay7199 in forum GM EFI Systems
    Replies: 7
    Last Post: 07-13-2014, 05:10 PM

Tags for this Thread

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
  •