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Thread: E38 idle tuning

  1. #161
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    Quote Originally Posted by ringram View Post
    I had same issue, not enough air no matter what min idle airflow. As above b1650 definitely puts more air in.
    438 cube with 230\240 cam.
    So I've got 4725 in here...what should I change it to ? Add 2%? 3%?
    Does this setting affect anything else?
    Mike

    I've gone 5% increase and try that tomorrow on cold start.
    Last edited by The Alchemist; May 6th, 2011 at 05:56 PM.
    "Just a tune > yeah right !!!! "

  2. #162
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    cold idle.efi

    Making b1650 smaller opened the throttle further I lowered it 5% to 4488.8 and the tps opened up to 21.2% where previously it only opened to 20.4% . this gave me a near perfect cold start and target idle 950 rpm met with about 26 deg timing instead of about 34 !
    awesume!
    Next day:
    Went -10% B1650 to 4252 and tried it today and got a high starting flare to 1700rpm and a tps of 21.6% cold engine. I also increased 1651/52 to 4.5 & 4 incase this was holding the throttle from opening past a certain "point"
    The extra 5% decrease on B1650 only increased the TPS from 21.2 to 21.6% so I'm going to increase B1651/52 to 5.5 & 5 (raising the hard limit) and see if the TPS opens a bit more.
    B1650 obviously affects other tables such as cranking idle air as it now flares badly on startup. Timing now down to an average of 26deg cold engine idle.....
    Interesting stuff really....
    Does anyone have any theories on what is the difference between B1701 and B1650 please?
    When you reverse calculate B1701 you end up with a throttle diameter or 102mm which I believe is what we have in the VE Holden V8s.....B1650 however is another story...
    Mike

    Set b1650 at -15% from original to 4016 and now getting 22% throttle cold start with even lower timing of about 22 deg. In gear drive hot or cold now ticks along beautifully at 800rpm as the throttle is open further vand the timing not over advancing trying to meet target. The other interesting thing is that starting at any temp now flares to 1700rpm BUT I believe this is becuase the throttle max opening has been increased allowing the throttle to open further on starting. Just my observations......Will adjust B1832 down by 5-10% or so and see how it goes
    Last edited by The Alchemist; May 9th, 2011 at 09:24 AM.
    "Just a tune > yeah right !!!! "

  3. #163
    Lifetime Member swingtan's Avatar
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    I've not fully worked out the {B1650} vs. {B1701} relationship yet.

    As you say, {B1701} indicates a 102mm dia throttle, but that's not actually the one in use on the VE. The lead in to the TB might be close to this, but the actual blade is much smaller. The specs say the vE runs a 90mm TB, but I'd say the blade is smaller still.

    If you use the stock values of {B1650}, you get a TB diameter of 77.5mm, which is about what I'd guess it would actually be.

    Why two tables with different values?

    I believe the labels given for these are taken from the GM documents, so don't always read well when you don't have the full documentation. They need some context to really be understood. The only difference between the two is that {B1701} adds the term, "effective"....

    Maximum effective throttle area of the ETC in square millimeters.
    where as {B1650} doesn't use the term.

    So I would assume that {B1650} is the literal setting for the TB size and is used by the ECM to calculate how much throttle opening is needed to supply a specific airflow. {B1701} is then possibly used as a correction factor, as there are times when the airflow may not match the expected flows. For example, peaks in the airflow may be at a level that match a bigger TB.

    Still working on a full understanding.......

    Simon

  4. #164
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    start up cold to hot.efinew cold to hot log

    this is my new cold to hot idle log with 22% max tps now with 22deg ave spark. smooth as silk now and you can tap it into gear and it just drives off like standard VE Holden
    The rest of the log shows in gear and out of gear with the spark and tps adjustments that the ECu makes. I also dialed back cranking idle air and the 1700rpm flare is goneburger.

    Also today with all this testing the ecu logged a p0606 code which apparently is not good. When this happened the start was very "saggy" and I had been doing a few start tests to sort the start flareup.... The water pump for the supercharger I/C also stays going if you leave the key "on"
    Suspecting low voltage causing this to trigger I logged this time with ECU Voltage pid. It seems it takes 7sec after startup for the ECU to report that its got 14.8volts, infact it stays on 11.4V for 4 seconds!...Is this normal ? Never checked it before so I wouldn't know...What do you think? This would be much worst if you had just been doing startup testing a few times so this may have been the problem
    Last edited by The Alchemist; May 9th, 2011 at 03:09 PM.
    "Just a tune > yeah right !!!! "

  5. #165
    Senior Member Dieselman's Avatar
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    Quote Originally Posted by The Alchemist View Post
    start up cold to hot.efi
    Suspecting low voltage causing this to trigger I logged this time with ECU Voltage pid. It seems it takes 7sec after startup for the ECU to report that its got 14.8volts, infact it stays on 11.4V for 4 seconds!...Is this normal ? Never checked it before so I wouldn't know...What do you think? This would be much worst if you had just been doing startup testing a few times so this may have been the problem
    Battery voltage is all controlled by the ECU on the VE's. Mine can take a while before it all kicks in. I think it calculates charge rates and battery percentages during this time....

  6. #166
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    start then stop.efi

    heres a log I did today showing a start then instant stop followed in 10sec by a start and everything OK. Logging batt and ECU voltage shows the voltage dropping to "0" just as it starts causing the engine to fall over.
    Discussing this with the owner revealed that "yes" it does this every now and then especially after a short stop over into a shop or at the petrol station, but had never mentioned it to me .....
    Something strange happening here...I'm going to check the charging and starting system tomorrow
    "Just a tune > yeah right !!!! "

  7. #167
    EFILive Reseller ringram's Avatar
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    Another convert

    Yes the B1650 setting seems to affect anything that happens when you drop throttle pedal to zero. So coast down, idle, transition, as well as startup etc.
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  8. #168
    Lifetime Member swingtan's Avatar
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    Not too sure about that one, but I don't think it's tune related.

    Back on to {B1650} and {B1701}. I did some testing over the past week and set these both back to stock. I have a 220/224 cam, so nothing too big and it did idle fine when hot and cold. However, on a dead cold start, it would fire and almost stall straight after firing.

    Example of near stall here

    This is where these tables really come in to play as I think they may influence the crank to idle air flow blending as well. I then pulled 5% from each table and the stall nearly disappeared completely, so I'm going to pull another 5% and leave it at that.

    So my advice would be for anyone that is doing cold start tuning, to drop these tables to aid is stability between crank and idle as well as cold idle airflow control. Suggested starting amounts would be,

    For a hot idle min air flow of...
    [list][*]5gm/S to 6gm/S: leave stock[*]6gm/S to 9gm/S: -5% to -10%[*]9gm/S to 15gm/S: -10% to -20%
    [list]

    The Alchemist has given us a good guide to dial the values in for fine tuning. Simply log the TPS% and watch how far it moves. Then use the idle spark technique mentioned earlier in this thread to fine tune the air flow.

    Simon.

  9. #169
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    Re: my starting issue falling over etc etc I removed that battery today and had it tested and its only doing 200amps at 9Volts
    :( so am fully charging it on a 7 stage charger and retesting in 24hrs otherwise new battery time!
    "Fully charged" at 50% CCA 7.2 Volts at 20deg C.......DEAD BATTERY OMG !
    Fitting a new one tomorrow and will retest cold start and see what the voltage does this time . Am also taking it to Holden Dealer to get latest BCM flash so the charge routine is up to date! Explains a lot
    Last edited by The Alchemist; May 10th, 2011 at 06:00 PM.
    "Just a tune > yeah right !!!! "

  10. #170
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    ok update on battery: al good now with correct charging and excellent starting now with 11.8V showing just after startup instead of about 11.2 and completely repeatable.
    Update on B1650:
    DON"T change this from standard as it seems to create a conflict with something else in the tables (maybe ones we can't see) and flags P0606 and reduced power mode in certain circumstances and driving conditions.
    It does make the throttle open further which is great for cold starting and in gear stuff BUT this P0606 popped up as I was sitting there engine off but key on testing starting etc...I pumped the throttle to 100% somewhat absent mindidly and up came the ECL with this code....WTF !
    I cleared the code and repeated this and it did it again !It also only reported about 36% tps even though I had my foot to the floor....stressing after reading what the code description said I did some research and came up with these links :

    http://hsv-gts.ls2.com/0506GTODTC/DTC%20P060D.pdf
    http://www.hptuners.com/forum/showth...t=31670&page=2

    all pointing to a conflict of some sort with the TAC ...
    I decided to flash B1650 back to normal and retry this test. This time 100% throttle got the 88.2% TPS that I wanted and no fault code popping up ! Whew.
    logs of fault and with it "fixed"
    In the fault recorded one go right to the end to see it, I also logged GM.CPUFAULT as per Blacky's suggestion to get a special number that he can check..in this case "22".
    I guess I'll find out what this means tomorrow.
    Attached Files Attached Files
    Last edited by The Alchemist; May 11th, 2011 at 07:23 PM.
    "Just a tune > yeah right !!!! "

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