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Thread: 06 Vette, LS2, 440 CI, Auto, 500 RWHP, Fast 102, big cam, ported heads - Cold Idle

  1. #11
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    OK I put the tune back in and my trouble code is ECM P0606 MF-HX-CI

  2. #12
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    I raised B 1650 all the way back up to 4500 before I gave up. What should I try next?

  3. #13
    Lifetime Member swingtan's Avatar
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    Sorry, I got caught in traffic on the way home....

    P0606 is an issue I've seen when changing B1650 too much. I've had one car that will throw the code when it's set to 4600, but not at 4900, so try 4900 and then work around to see what gives the best results. Your only other option is going to be to drill a hole in the TB blade to try and get some more air flow. I normally don't like drilling a hole as it can cause other issues, but it may be your only choice if B1650 won't play nice.

    Simon.

  4. #14
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    Quote Originally Posted by swingtan View Post
    Sorry, I got caught in traffic on the way home....

    P0606 is an issue I've seen when changing B1650 too much. I've had one car that will throw the code when it's set to 4600, but not at 4900, so try 4900 and then work around to see what gives the best results. Your only other option is going to be to drill a hole in the TB blade to try and get some more air flow. I normally don't like drilling a hole as it can cause other issues, but it may be your only choice if B1650 won't play nice.

    Simon.
    4725 is where B1650 (max throttle area) was before. What about those other settings for max throttle area B16151 and B16152? Are those causing the code? It seems like just those setting alone would help the situation but I guess I don't understand what is going on. Would it make sense to try increasing them to a higher number or put B1650 back to where it was and leave those at 4%? Why would those settings alone not be an effective way to increase idle air?

    If I am able to get B1650 (max throttle area) to decrease to lets say 4600 then what would I do with my idle air table? I guess start moving it back up to higher numbers? It seems like what you are saying is that the idle air table does no good beyond a certain point with the max throttle area set to 4750 is that true? This is why we were able to set it at 40 and it did not solve the problem. What point is it that it is no longer effective how do I know when I reached that point or is it just trial and error?

    My original tuner did drill a hole in my throttle plate but I replaced it with a new one (still have the old one). Perhaps he already did this excessive. However he was unable to get the car to do much of anything right. It didn't start well hot or cold and did not idle well hot or cold. My new tuner asked me to get rid of the hole and we started tuning from there, now I am down to cold idle only problem, as soon as it warms up it is OK.

    Last night when I decreased B1650 both the hot and cold start and idle did improve dramatically, at one point I was able to lower the idle from 800 to 700 and it was still pretty smooth, so I agree it does seem to have us on the right path. In fact when it was learning it idled down to 600. Idling lower is important to me becasue I have a stock converter.

    I just had another idea what about 102mm throttle body would that help with the idle airflow?
    Last edited by RD in SD; November 19th, 2012 at 06:28 AM.

  5. #15
    Lifetime Member swingtan's Avatar
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    {B1651} and {B1652} set the maximum amount of throttle for idle control, so I don't think these will help with cranking, though they may help slightly. As I mentioned previously, there seems to be a fixed max setting that we don't have access to, hence why we try to fool the ECM into thinking it has a smaller TB, so it opens further. I would however, try setting these to around 4% to see if it helps. The idea to to get the base idle air flow correct, so the ECM doesn't need to adjust by too much. Ideally we would set these very low if we could get the min idle air flow tables spot on.

    Changing {B1650} to a lower number doesn't seem to have a great effect on the min idle airflow table {B1829}. I really think it's a setting that is only used in the theoretical calculation of how far the ECM has to open the TB for a given air flow, but {B1829} is an actual measured air flow setting. So one will not impact the other. though I think there is some rational checking between the settings. To get a working value for {B1650}. I'd try a bit of binary sorting..... If 3600 throws a code and 4725 is stock, try half between the two, about 3900. If that doesn't throw a code, but doesn't have sufficient impact, try half way between 3900 and 3600. If 3900 still trows a code, try half way between 3900 and 4725. then just continue making smaller steps till you get as good as you can get.

    Here's my thoughts on drilling holes. It helps for some things, it hurts for others. My main reluctance to drilling holes is trying to balance hot vs cold idle. With a hole in the TB blade, you need less commanded air flow, as the hole lets more air in to the motor than the ECM is commanding. so you may only command 5gm/S at idle, when really the engine is consuming maybe 10gm/S. So as an example, the hole may be letting in 5gm/S of additional air. When the engine is cold, you command much more idle air to help it idle after starting, may cammed cars will want 2X the airflow when cold, so you max out the ECT idle air correction to 2X. The problem is that you are only commanding 5gm/S of idle air in the ECM, so 2X is only 10gm/S, and in the 5gm/S from the hole and you only get 15gm/S instead of the desired 20gm/S. You can see how balancing hot and cold idle air flow becomes difficult. It will come down to the trade offs you are willing to go for. Hole or no hole they both have good and bad points.

    The NW 102 would in theory help, as it is bigger than stock so should give more idle air flow. However, I've not seen any specific tuning data for the NW, which is a bit of a shame. It also has a tendency of introducing idle correction over shoot as it gives more throttle opening for each degree of shaft movement, especially at small openings. This can introduce hunting issues that cause the ECM to over correct at idle. If NW was to release specific idle tuning data, it would help a lot. just like some of the better injector companies provide specific tuning data for their injectors.

    Simon.

  6. #16
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    I have not yet had a chance to get back to the car yet.

    My cold problem is idle only, it starts fine, no cranking issues so it sounds like maybe B1651 and B1652 alone might help me, would you agree? Do those ever throw codes when you crank them up to 4%?

    With the 102mm throttle would it be safe to assume we could expect about 10% more air for any given situation? Seems this might be a possible solution. My engine builder seemed to think that I was leaving some horsepower behind with out one anyway. Frankly I thought it would just create another tuning problem? The engine is a 440 with a large cam so it does need a lot of air.

    I know a trick that can be done by making a physical adjustment to the TPS. This is done by elongating the mounting holes in it and rotating it. This will change where the car thinks the throttle is and can work to increase or decrease air to some extent. I do have experience doing this on another car and it did work for a different situation by by tricking the TPS into believing it was further open that it really was to reduce air, we might do that same thing here to have the opposite effect and increase air. What do you think?

  7. #17
    Lifetime Member swingtan's Avatar
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    I think I'd rather drill a small hole in the blade rather than elongating mounting holes

    B1651 and B1652 may work for you, if it does then go that way. Really there's no single fix for everything, so use what works They don't throw codes, but are still governed by the maximum TPS opening limit. SO setting them to 50% may not help, just like setting the min idle air to 40gm/S didn't make a difference.

    Perhaps the 102 is the best choice here, though I'd still test out B1650 to see if that does the trick. Then I'd probably look at the 102 to help the top end of the bigger motor.

    Simon

  8. #18
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    Quote Originally Posted by swingtan View Post
    I think I'd rather drill a small hole in the blade rather than elongating mounting holes

    B1651 and B1652 may work for you, if it does then go that way. Really there's no single fix for everything, so use what works They don't throw codes, but are still governed by the maximum TPS opening limit. SO setting them to 50% may not help, just like setting the min idle air to 40gm/S didn't make a difference.

    Perhaps the 102 is the best choice here, though I'd still test out B1650 to see if that does the trick. Then I'd probably look at the 102 to help the top end of the bigger motor.

    Simon
    Success, I increased B1651 and B1652 to 4% and got a code. Changed them both to 3% and it worked great except the idle was a bit to high so I lowered the idle air tables down to 15 and its better. I have some more tweaking to do to make it perfect but overall that solved the problem, it started and idled cold and hot with no code. What a simple solution to a problem I have been doing battle with for a while. Thank you very much for your help. I will post again after I get it all dialed in so others can learn from it.

  9. #19
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    Update,

    As I said in my last post the cold idle stuff is all worked out after lots of playing with the idle air table, the coolant correction and the idle speeds. Lots and lots of trial and error and probably over 100 tunes.

    Right now I have it idle pretty smooth in gear at 725 and 750 in P/N. However with the idle that low and everything else working well at low speeds it does not like to shift from D to R, it dies about 25% of the time and when it does go in without dying it slams in hard and the car jumps back. I have played with the reverse idle air and the in gear correction table a lot to try and smooth this out. I have come to the conclusion that it is the shift pressures or shift timing in my highly modified transmission tune that won't let it slip into gear nicely. It only does this when transitioning from D to R all other shifts are fine. It goes like this: shift from D to R, 1 second delay during which time engine revs to 900 or 1000, car slams into reverse and car jumps, sometimes engine dies and sometimes is stumbles.

    In addition when decelerating to a stop at around 2 MPH the transmission downshifts from 3 to 2 and the car jumps forward as the engine revs up a little and it shift. It used to do it twice until I lowered the 2 to 1 shift point to 0 now it shifts after I stop. The strange thing is that the 3-2 downshift is programed at 24MPH. This problem does not occur if I hold it in second in tap up tap down mode.

    Lastly the car transitions from the idle table to some other table at 2MPH (factory setting that can be changed) what table does it go to? When it transitions my idle goes from 725 to 900 and the car accelerates to 6 or 7 MPH so I am driving around parking lots with the brake on. I think the table it goes to has to do with in gear RPM at idle that I have seen in HP tuners but can't find it in EFI live. I wonder if that is what is causing the problem described above as well?

    Any suggestions would be helpful.

  10. #20
    Senior Member MyM8V8's Avatar
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    Hi Guys.

    Just seen this and I have just installed a 457 LS2 in my Maloo. I'm running a fast 102 intake with the NW 102 TB through a Duspeed OTR. Its got a big cam 25x 26x with some lift too. I've got a base tune in a looking to get it to idle.

    Not wanting to be a parasite, but I would just love to see your idle tables now you have sorted yours??? Did you drill or not drill?

    Regards.
    2005 HSV Maloo Ute, HKE 457ci Stroker LS2 E40, TFS 245's, 255/263 Hi Lift HUC, FAST LSXr 102, NW Billet 102 TB, FLT Level 7 4L65E, CircleD 4200 stall, Duspeed OTRCAI - Mafless, DF 1 7/8" LT's, 3" DiFilipo Duals, Serial LC-1 WB's



    "An Old Dog learning new tricks"

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