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 13 of 13

Thread: Tuning Advice needed

  1. #1
    Fuel Injected!
    Join Date
    Oct 2014
    Posts
    40

    Tuning Advice needed

    Hi Guys, hopefully someone can share some wisdom with me.

    I am using EBL Flash trying to tune an old Pontiac 4 cylinder running a dual throttle body injector, 4 speed manual. I am done a couple VE learns so far and am slowly correcting an over all rich condition. I know I need to continue doing this but after 5 'learns' I have two issues that don't seem to be getting any better.

    1. While driving and pushing in the clutch, the engine will slow and often die. Idle is set at around 1000. If I am parked, it will idle fine. This happens at most every stop. Engine is fully warmed up. What do I need to adjust here? Since I appear to be rich every where it doesn't seem that I need any more fuel here.

    2. Most every time I get on the throttle and hit 3000 RPM, I start to backfire (thru the intake I believe).

    As I said, I know I need to continue with the VE learns to get the AFR where it needs to be but I'm not seeing improvement in these area's so I am wondering is there something else I should look at? I haven't done anything with Spark yet. Any rule of thumb to know when more spark is needed, or do you just raise it until it knocks?

    Attached is a data log from my most recent run.

  2. #2
    Super Moderator
    Join Date
    Mar 2011
    Location
    Camden, MI
    Age
    29
    Posts
    3,026
    the engine dying when the clutch goes in could be one of two things: a clutch pedal position switch not being detected, or should your calibration not use one, the IAC throttle follower needs adjusted so that when you let off the throttle, the IAC keeps a little further open than it does now.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  3. #3
    Fuel Injected!
    Join Date
    Oct 2014
    Posts
    40
    I found a parameter in TunerPro called Stall Saver. I raised these values however that did not did not improve the problem with it dying when I push in the clutch.

  4. #4
    Fuel Injected!
    Join Date
    Oct 2013
    Posts
    900
    You might be in DFCO as you're coming to a stop and with no fuel to the engine when you clutch in and the RPM's drop it can't get out quick enough. I doubt it, but maybe.

    You really need to figure out if that misfire is a mechanical issue or tuning. It could be a mechanical problem that is also causing the stalling. Also, you can't tune-out a mechanical issue.

  5. #5
    Fuel Injected!
    Join Date
    Oct 2014
    Posts
    40
    I am pretty sure I see in the data log that when the clutch is in and the engine starts to go below the idle RPM, the IAC is opening up, as it should based on the stall saver. Should I command the stall saver to open the IAC more, or is there another setting that is more appropriate? I see there are multiple IAC settings.... and I never know if I should be trying to correct a problem by adjusting the timing.

  6. #6
    Super Moderator
    Join Date
    Mar 2011
    Location
    Camden, MI
    Age
    29
    Posts
    3,026
    the EBL is running on its own code(I believe it's a "from scratch" OS from RBob), hard to say what exactly you need to mess with since what is available and how it is defined might be a bit different from what was used in GM code.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  7. #7
    Fuel Injected!
    Join Date
    Oct 2013
    Posts
    900
    Throttle off coasting right before the clutch is disengaged or something different?

    What happens if you bring up the rpms when idling and then snap the throttle closed? What do the IAC counts do when you do this? There should be some type of throttle and/or speed following tables for the IAC that open the IAC as the throttle opens and/or the speed increases.

    Is there some kind of idle timing table that is different than the main table?

    Did you find any DFCO parameters?

  8. #8
    Fuel Injected!
    Join Date
    Nov 2012
    Location
    Maine
    Posts
    39
    Some manual bins have increased timing in the sub idle area to help with this kind of thing..if its not there already..
    try adding 4* to the 400rpm line in the idle / stall area of the timing table(if 16*in 800rpm,then 20*in 400rpm)...
    Last edited by CFI Z51; 07-27-2015 at 02:30 PM.

  9. #9
    Fuel Injected!
    Join Date
    Oct 2014
    Posts
    40
    Quote Originally Posted by lionelhutz View Post
    Throttle off coasting right before the clutch is disengaged or something different?

    What happens if you bring up the rpms when idling and then snap the throttle closed? What do the IAC counts do when you do this? There should be some type of throttle and/or speed following tables for the IAC that open the IAC as the throttle opens and/or the speed increases.

    Is there some kind of idle timing table that is different than the main table?

    Did you find any DFCO parameters?
    The problem occurs throttle off, clutch in. Throttle off, coasting does not present any problems, until clutch is pushed in.

    Yes... There are multiple spark tables. SA- Initial, SA - Idle State, SA-Main, SA-Extended. Plus about 10 others. What should I be looking for?

    Yes, there are about 10 or more DFCO parameters. I have not changed any of these parameters. What should I check?

  10. #10
    Fuel Injected!
    Join Date
    Oct 2014
    Posts
    40
    Quote Originally Posted by CFI Z51 View Post
    Some manual bins have increased timing in the sub idle area to help with this kind of thing..if its not there already..
    try adding 4* to the 400rpm line in the idle / stall area of the timing table(if 16*in 800rpm,then 20*in 400rpm)...

    I'll give this a try. Thanks.

  11. #11
    Fuel Injected!
    Join Date
    Oct 2013
    Posts
    900
    How bad does the rpm's drop? Also, this?

    Quote Originally Posted by lionelhutz View Post
    What happens if you bring up the rpms when idling and then snap the throttle closed? What do the IAC counts do when you do this?

  12. #12
    Fuel Injected!
    Join Date
    Oct 2014
    Posts
    40
    Update. I adjusted the throttle blade screw and the IAC to get the counts down. Doing this brought my IAC value at idle down from in the 60's down to around 15. This made a world of difference. Now when I put the clutch in, the rpm's stay pretty steady. Dying problem is gone.

    Now my remaining major issue is some backfire thru the intake while driving. Is intake backfire typically a fuel or spark issue?? I haven't attempted to do anything with the spark advance yet. Though I know I still have more work to do to get the A/F right with the VE tables.

  13. #13
    Fuel Injected!
    Join Date
    Oct 2013
    Posts
    900
    Good you got it fixed but that sounds like the IAC was retracting and you fixed it by limiting the travel. Did you find any tables giving IAC position vs speed data? If IAC was 60 at idle then it should likely be >60 at any higher engine speed.

    The backfire could be a lean condition or a misfire/crossfire.

Similar Threads

  1. Replies: 15
    Last Post: 11-16-2014, 07:52 AM
  2. Advice on knock sensor for tuning newb
    By edfiero1 in forum GM EFI Systems
    Replies: 8
    Last Post: 11-03-2014, 08:08 AM
  3. turbo lt1 tuning advice needed
    By supr67 in forum OBDII Tuning
    Replies: 4
    Last Post: 02-13-2014, 03:46 PM
  4. needed: maf tuning info
    By steveo in forum GM EFI Systems
    Replies: 0
    Last Post: 08-29-2013, 11:56 AM
  5. Equipment needed for tuning
    By Xenon in forum Gear Heads
    Replies: 13
    Last Post: 03-20-2012, 09:08 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
  •