CBAZA Trends timing not following tables

Discussion in '1994 - 1995 Specific Tech' started by R100RT, Oct 24, 2007.

  1. Hi Tuners,

    I'm pulling my hair out, and I don't have much left! I am setting timing use base table, altitude and MBT table set to 55, all adders and retards zeroed out. Global adder=0, multiplier=1, load switch 0. I researched Gradys website, reviewed his tune, compared to mine and I can't find the problem. The problem is that I am datalogging timing higher than any tables. Sometimes, it looks like the timing matches, sometimes not. It can be as high as 6 degrees more than called for in the base table.

    As far as I understand, using the loadx and rpm, I should see my table timing match the datalogged value. I'm using 1.30(7) I'm using the J4J1 tune as a base.

    Looking for ideas here.

    thanks Eric
  2. hmm... what's your timing at the dizzy?
  3. Two things come to mind

    If you had your dizzy at say 16 ... the pcm would not know it

    You did not talk about the borderline table :shrug:
    What have you done about it :shrug:

  4. Post up your log and tune and we'll get to the bottom of it.

  5. Grady, BDLN table set to all cells 55

    Wes, not sure how to post tune and data log. Files won't attach normally.

  6. Eric

    Have you tried one of those hosting sites like ... Photo bucket :shrug:

  7. More information:

    The tune I posted yielded 45 degrees timing at high loads! Talk about ping!
    For my EEC, it does not seem to follow the spark base table at all and is certainly not taking the lowest spark of the three tables.

    Thanks, Eric
  8. Try now. The data log should be good.
  9. Eric

    I did not see a prob :shrug:

    MPH was not included :(
    It appeared you were just puttin around in Closed Loop :)

    I took a real quick look at the raw data in column form only

    I saw these trends :D

    36 to 46 spark at a load of 19-35 with throttle at 1.2-1.5
    As the load increased ... the spark decreased
    Is to be as expected

    The greatest amount of throttle I could find was .........

    1.7 with a load of 60 and the spark fell to 33
    which again
    Is the normal kind of thing to be expected

    When in a low load or Closed Loop kinda driving condition ..........
    high spark values are not all that uncommon

    The base spark table is all about Open Loop
    You are gonna have to cross over to those drivings conditions before
    you'll see the values in your d logs you call for in your tune :)

  10. why would you change the MBT table to 55 ? If anything you should have left that alone or just scale the table up 4-5 degrees that way it will still act as a limiter on your timing ...
  11. Grady,

    I didn't realize that closed loop operation didn't following the spark tables. My thinking was that the spark should be the lowest of the three tables, all the time. I guess thats not right. Comparing the three tables, to the logs, clearly shows they don't follow the table. That was the basis for my request for help and understanding. The tune I posted gave 40+ timing under high load and higher spark durring cruise, by 6 degrees, than any number in the three tables. I still don't think I have a good handle on this. Popular belief is that the EEC picks the lowest spark and thats not true in my case. Perhaps, I need to go into open loop sooner, if I want to control my spark.

    2002BLGT, The MBT table was set to all 55s in an attempt to get control of the spark. There is much difference in opinion on the effect of this table. Some say it's just a guide, others say it's a limit. The BDLN table was also set to 55s, in the tune I posted. What I was attemting to do was to get one table to control the spark. I was following popular thinking in setting the tables to 55. The results were not as predicted by popular belief. I ran across another post about this same topic, where I guy zeroed the tables and ended up with more spark than what the tables called for.

    Thanks for the time you guys took reviewing the logs.

  12. Eric

    I see more clearly now what you are concerned about :)

    Allow me to point you in the right direction to get a handle on
    how the pcm arrives at a final spark value.

    Spark table operation has been explained on the various tuning sites :nice:
    I won't go into all that as it is just wasted time in this discussion :bang:

    IMHO ... I'd have to say popular belief is not the problem here :nono:

    Here is what I'd do if I was you :D

    Get a fundamental grasp on the tables operations ;)
    Then consider your particular application ... which is forced :eek:
    Finally ... base your table tweecs to work well with your application :)

    Application is ALWAYS key as to why one does things as they do :Word:

    That stuff you find on my site is accurate and valid :D
    It is not working
    It is not gonna work for you ... for two reasons :(

    1) You're looking for it to work under CL and the tables are all about OL
    2) As was said by the poster above ...

    It would not be in your best interest to ...
    Mimic my NA combo with your FORCED combo

    So ... What do you think my friend :shrug:
    Any of this stuff make sense :D

  13. it acts as a limiter as long as you do not set it below what the other tables are at , if you set it to zero and the other tables that it sees are all higher than zero then it will never see the table to read what to keep it below in other words , setting it to all zeros is basically going to disable it ....
  14. Hi Grady,
    I think I am causing problems with my sig. My '65 Fastback,(A9S), sig car, runs great. Makes about 560HP and has been reliable for three years, except for some shuffling on occasion. The car I am talking about ihere is my '94 Vert. You may remember an earlier post "$600 Vert"?. Anyway, it's a 331 based stroker, GT40Y heads, Cobra intake, TF stage 1, BBK Shorties, 70MM TB, 24#. It's my commute car.

    I have spent hours reviewing posts on spark tables but I never recall reading that they don't apply in closed loop. I'm still not sure what is going on but I think I am convinsed that my next tests will show the spark right where it's supposed to be in open loop. This all started when I needed to deal with a moderate cruise load pinging at around 1500-2000 RPM closed loop. The next tune will drop open loop to about 55% loadx. The problem occurs right around that point.

    So, what does control spark in closed loop? Don't hold back now, I'm pretty smart you know!:eek: <-- Grady speek

    By the way, the fastback runs about 20 degrees WOT and I'm sure your 34 degress would destroy the motor! Don't worry about me sending you a bill! :D <-- more Grady lingo

  15. Eric

    I'm off to a family thing for the night so I got no time right now :(

    I bet Wes or some of the others will chime in :)

    I should have placed a focus on WOT/max load in my above info
    I may have side tracked you a bit

    I should have not talked CL and OL I guess :bang:
    simply because
    The spark tables are a load kind of thing :D


    Do you understand the top row in the base table is the greatest load row
    There is where you do your WOT tuning ... definitely OL here :rlaugh:

    Gotta Go! ... Hope I did not hurt more than help you ;)

  16. If its mid load ping...on an N/A combo...

    Is the EGR working and hooked up? If it was removed (and not turned off) or is not working properly mid load timing goes up (were EGR works, mid load) and the eec expects more fuel (from the EGR being in use). Both will lead to a ping and maybe even a surg/bucking as your timing/fuel is out of wack.

    With the MBT/Alt./BDLN the EGR tables are still working.

    For me the best way to think of the tables is a ven diagram...we just take a few tables out (not all) to ease our will over the eec.
  17. Ha, you had me confused for a second too -- I was looking at the stock MAF curve and high timing wondering how you hadn't blown up that engine yet. :)

    How's your fuel looking with those 24# injectors? Could be a tad lean up top depending on how high you are spinning it, just something to consider.

    The base spark table that you are tuning out of is where your spark is coming from. It's very common to see high timing at light loads... hell, I run more than stock timing on my blown car (13#) up until around 80 load and then I start pulling timing. There are some adders etc that take place but the few I checked were zero'd out.

    Check the twEECer manual, it's got a good explanation of the spark calculations etc.

    blksn955.o is dead on mentioning the EGR, I see it's not disabled in the tune, could hose with something if it's plugged, broke etc. Vacuum leaks after the MAF will also let more air in than the PCM knows about causing a lean issue, the log you posted was pretty short - not sure where you were seeing the ping.

    Otherwise man, your log looks a-ok to me. If you are getting some ping, I'd start with cleaning the MAF and checking the fuel filter, fuel pressure. Some guys run seafoam in over the brake booster hose to knock the carbon out of the cylinders and claim it solved their ping.

  18. Eric

    Please allow me to make things a bit more clear than my earlier attempt :chair:

    You mentioned briefly ... spark taken from the lowest table :)
    That can be the case if you got all four active :nice:
    Other adders and what not can really hose with things :bang: :crazy:

    Lets just keep it simple for the time being :banana:
    Focus on the base table without other interference ;)

    btw ... If you have not updated your cubic inch scalar for the stoker,
    your load is gonna be all hosed up


    Since you use a load switch value of 0 ......
    your top load row in the table is definitely gonna be WOT

    Using the dlog you provided ....
    I'd say you were using load rows .2, .3, & .4 for most conditions

    Now ... Take a look at your file and see if what you command in
    those load rows more closely matches the values you see in
    that dlog.

    I can't look at V1.30 stuff so I'll take Mr. Wes at his word
    about you killing out most of the spark adder stuff so we
    will hope nothing is adding value to the base table :shrug:

    Again ... Sorry about going down that CL & OL road :doh:

    You wanna use LOAD to determine the spark thing :nice:

    Greg, Wes, and 2002BLGT have made some very good points
    for you to consider :hail2:

    Let us know what you find Eric :D