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  • Cold tuning $A1

    So I'm getting back into tuning a bit after a long hiatus of working on other vehicles.
    89 Z24 with 94 3.1L swapped in, all stock, except for the tune, BFUZ code.
    I did a bunch of tuning in the summer, and now my VE is close and I added a couple degrees of spark and smoothed a bunch of tables out.

    Now it's winter up here in Alberta and I'm doing some datalogs and I'm questioning some of the AFRs I'm seeing. Is it really necessary for the ECM to be commanding 7.xx and 8.xx AFRs for the first several minutes after a -30*C startup? I mean, I can understand it commanding ratios that low in the first few seconds, but after it's started, shouldn't the AFRs jump up into the low 10's at least? I mean, this IS a port fuel injected engine, it's not like there's much fuel sticking to the intake manifold like the old TBI's. It's no wonder I'm getting a 6mpg drop in the winter lol (I don't idle my car for more then 30 seconds ever).

    So what I'm thinking of doing is drastically reducing my A/F timeout table (from the factory that table is set to -5.0 AFR below -16*C), or reducing the timeout decays, or both. I think I'd reduce the A/F timeout to maybe -2.0 or -2.5 AFR, and reduce the decays by about half.

    I'm also looking at slightly increasing my open loop AFRs in the main Open Loop VE table in the cold areas. I originally thought to remove the timeouts all together and only use the Open Loop VE table, but wasn't too sure about that idea. I don't think there's any real damage to be done except for some stalling if I go to lean with a cold engine, so I'm not all that worried.

    What (if anything) have you guys done with your cold open loop stuff? Anyone care to post their Open Loop fuel tables and their A/F timeout tables? Doesn't matter if your engine is stock or modded.

    I've attached the factory tables, so you know what to look for. Notice the A/F timeout table that has you at -3.1 AFR even at a 44*C warm startup! That seems a tad ridiculous to me.
    Attached Files

  • #2
    One thing you could do is use a heated 4 wire O2 sensor. Then you can reduce the time it waits to go closed loop. That right there will help a lot. There is a how -to on www.v6z24.com
    sigpic New 2010 project (click image)
    1994 3100 BERETTA. 200,000+ miles
    16.0 1/4 mile when stock. Now ???
    Original L82 Longblock
    with LA1, LX9, LX5 parts
    Manifold-back 2.5" SS Mandrel Exhaust. Hardware is SS too.

    Comment


    • #3
      Yeah I know I could use a 4 wire O2, but it's not the solution I'm looking for. I'm trying to get more tuning experience with this car, I'm not planning on doing any mods to it whatsoever (it's a junk car I drive right now).

      Comment


      • #4
        most $A1 .xdf's don't have the timeout tables mapped.

        I never messed with them, just the open loop commanded afr tables and the main timers because i was using a heated o2.


        You'll probably run into stalling problems or you'll find that those tables make no difference at all.. lol

        I'll +1 on the heated o2, then bump your cold closed loop timer up to 60 sec, warm to 30 and hot to 10. That'll save you fuel right off the bat.
        Past Builds;
        1991 Z24, 3500/5 Spd. 275WHP/259WTQ 13.07@108 MPH
        1989 Camaro RS, ITB-3500/700R4. 263WHP/263WTQ 13.52@99.2 MPH
        Current Project;
        1972 Nova 12.73@105.7 MPH

        Comment


        • #5
          Originally posted by Superdave View Post
          most $A1 .xdf's don't have the timeout tables mapped.
          yeah, i'll agree with that... mine doesn't have them, now i'm jealous

          i guess i'll have to run through the hack again and add them...

          but here's my open loop AFR setup... works well for the GP.

          EDIT: now with all of the Choke tables...

          DOUBLE EDIT: apparently PNGs get resized and saved as JPGs.... TIFs work though.
          Attached Files
          Last edited by robertisaar; 12-08-2009, 02:50 PM.
          1995 Monte Carlo LS 3100, 4T60E...for now, future plans include driving it until the wheels fall off!
          Latest nAst1 files here!
          Need a wiring diagram for any GM car or truck from 82-06(and 07-08 cars)? PM me!

          Comment


          • #6
            FYI, another reason for a drop in mpg in the winter is the winter fuel blend which I believe happens in late-September or so here in Ohio. Not sure up there.

            -- Scott

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            • #7
              I've already reduced my closed loop timers to 20/40/120 seconds, and it works well for me even with the 1 wire O2. Like I said, that's not the solution I want.

              I think it's a problem even if I'm only in open loop for 60 or 120 seconds but for that entire time I'm seeing 7.x or 8.x commanded AFRs.

              Unfortunately it doesn't look like many people have messed with this area of tuning, so I'll have to pioneer this one myself lol.

              ps. I think I've asked this before, but does anyone know how the ECM determines what an "Injection" is? Judging by those A/F timeout tables, you would think a number such as 48 or 64 or even 160 injections would happen in much less then a second, because the injectors fire very rapidly. Datalogs show that the decay happens over the course of several seconds, so there must be some difference between a single batch fire of the injectors and an "Injection".
              Last edited by discostu; 12-08-2009, 09:47 PM.

              Comment


              • #8
                what's commanded and actual afr's rarely match.. especially in open loop.


                you need a wide band to actually tune that, there is no way you will be able to get close with a cold narrow band. IMO completely pointless for 2 minutes of runtime.

                I've never seen the commanded AFR's do anything in $A1 other than in lean cruse mode. The PE commanded AFR and the open loop tables never made a bit of difference in the 40+ cars i've tuned.
                Past Builds;
                1991 Z24, 3500/5 Spd. 275WHP/259WTQ 13.07@108 MPH
                1989 Camaro RS, ITB-3500/700R4. 263WHP/263WTQ 13.52@99.2 MPH
                Current Project;
                1972 Nova 12.73@105.7 MPH

                Comment


                • #9
                  i haven't seen half of those tables. choke, decay rate, injector pulses? what .xdf are you using?

                  discostu...did you ever end up with the full version of the A1 .xdf file?

                  i've been playing with cold loop for months to try to consistently lean rpm vs. map. my 02 mV reads either very low (.300 or less), or very high (950-1000). my main reasons are to save some gas and to keep the engine from bogging down when i put it in drive when cold. that only happens within the first 30 seconds and the first time i put it in drive. also, the 02 drops from 950mV to 100mV as the rpm drops from 1200 to 500. i've tried richening the idle tables-rpm vs. map, and added a couple of degrees to idle underspeed spark table. that has helped quite a bit. what sucks about cold tuning is, you only have a minute to log, and have to wait several hours in order to test a change. takes for ever!!
                  Andy

                  sigpic

                  fastest 1/8: 10.19@ 67.17
                  fastest 1/4: 16.16@ 82.70

                  62mm TB, 1.6 roller tip rockers, Ostrich 2.0, UD pulley, TB heater bypass, K&N, 180* stat, No cat, 99Grand AM dual cooling fans. 4T65E swap FDR 3.69, EP LSD, F.A.S.T. transmission controller, TransGo shift kit.

                  Comment


                  • #10
                    my newest A1 XDF is on the tunerpro website... it's very damn complete if you ask me. i just left out some co-efficient stuff...
                    1995 Monte Carlo LS 3100, 4T60E...for now, future plans include driving it until the wheels fall off!
                    Latest nAst1 files here!
                    Need a wiring diagram for any GM car or truck from 82-06(and 07-08 cars)? PM me!

                    Comment


                    • #11
                      i just see a listing of everything. what if i wanted to use that file in tunerpro?
                      Andy

                      sigpic

                      fastest 1/8: 10.19@ 67.17
                      fastest 1/4: 16.16@ 82.70

                      62mm TB, 1.6 roller tip rockers, Ostrich 2.0, UD pulley, TB heater bypass, K&N, 180* stat, No cat, 99Grand AM dual cooling fans. 4T65E swap FDR 3.69, EP LSD, F.A.S.T. transmission controller, TransGo shift kit.

                      Comment


                      • #12
                        listing? i'm guessing you're still using TPV4? if so, get the latest version of V5 and download the V5 only XDF, it has more stuff in it and has been updated a lot more recently...
                        1995 Monte Carlo LS 3100, 4T60E...for now, future plans include driving it until the wheels fall off!
                        Latest nAst1 files here!
                        Need a wiring diagram for any GM car or truck from 82-06(and 07-08 cars)? PM me!

                        Comment


                        • #13
                          no idea what TPV4 is or how to upgrade.
                          Andy

                          sigpic

                          fastest 1/8: 10.19@ 67.17
                          fastest 1/4: 16.16@ 82.70

                          62mm TB, 1.6 roller tip rockers, Ostrich 2.0, UD pulley, TB heater bypass, K&N, 180* stat, No cat, 99Grand AM dual cooling fans. 4T65E swap FDR 3.69, EP LSD, F.A.S.T. transmission controller, TransGo shift kit.

                          Comment


                          • #14
                            tunerpro V4 = TPV4

                            i don't have to explain TPV5 do i?

                            it's still in the 'beta' stage, but it works damn good...

                            of course, with V5 you'll need an ADX in place of an ADS, but there's also quite a few improvements there as well...
                            1995 Monte Carlo LS 3100, 4T60E...for now, future plans include driving it until the wheels fall off!
                            Latest nAst1 files here!
                            Need a wiring diagram for any GM car or truck from 82-06(and 07-08 cars)? PM me!

                            Comment


                            • #15
                              ohh lol. i though it had something to do with some program on my computer.
                              Andy

                              sigpic

                              fastest 1/8: 10.19@ 67.17
                              fastest 1/4: 16.16@ 82.70

                              62mm TB, 1.6 roller tip rockers, Ostrich 2.0, UD pulley, TB heater bypass, K&N, 180* stat, No cat, 99Grand AM dual cooling fans. 4T65E swap FDR 3.69, EP LSD, F.A.S.T. transmission controller, TransGo shift kit.

                              Comment

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