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Thread: 2015 GMC Sierra Mapping of gear for tip in limit table

  1. #1

    Question 2015 GMC Sierra Mapping of gear for tip in limit table

    I need some help.

    I am tuning a 2015 GMC Sierra. It is an off road vehicle cats removed.The exhaust is Patriot Full length headers with 3 inch duels into two 40 series FlowMasters and duel 3 inches out in the stock location. A lot of changes to accommodate that. The timing and cranking tables in particular. I searched the tables and tuned out applicable retards. Start up is now great sounding without the blast of fuel and timing retard lighting in the headers for the first 70 seconds. During shifts however, the Torque Management is obvious during the shift. I detect the sound of timing retard during the power cut for the shift. Also, the drive by wire is to sluggish. Finaly, I cannot find any cam timing ability.

    1) Will it help if I set transmission>Torque Management>Tip In TqMgt>Upshift to "Throttle Only"? It is my understanding this will cause the throttle only torque reduction correct?

    2) I have modified the "Tip-in Limits" on Gen IV's for some better throttle response. I see under Engine>Torque Management>General>Mapped Gear what seems to be tip in information. I cannot seem to find what the table represents. It seems to point to some form of mapping per gear but, I can't tell what the values correlate to. Can anyone help?

    4) What prevents you from revving the engine in neutral?

    3) Where do you look at the cam timing?

    Thanks everyone who posts on this site. I have gotten quite an education through the years!

  2. #2
    Advanced Tuner IARLLC's Avatar
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    Sounds like a fun project!
    1) I think that the factory setting is better in this case. If you use throttle instead of timing to moderate toque during shifts I expect a bigger lag. I am pretty sure it can reduce and increase timing 1,000x faster than closing and re-opening the throttle for that split second during the upshift.
    2) These can be pretty sensitive to adjustments that affect throttle application to say the least. Some of the other guys with more GEN5 experience have written recently about throttle response issues. I know that I don't like the unpredictable "Driver demand" settings under Engine>Torque Management>Engine. A bit of smoothing on Map A - Normal makes more predictable throttle transitions and better response. I am not sure how for a person can take that before the system starts to complain but I have been really happy with small changes there.
    4) Engine>Fuel>Cutoff,DFCO>Cutoff RPM vs. Gear, 4000 limit in Neutral and Park. I have not raised this on a GEN5 but expect it is the same as others....maybe.
    3) Cam timing is at Engine>Airflow>Variable Camshaft>Intake Camshaft>>>> After making changes to the high baro table I adjust the WOT table to match any changes I made to the WOT region in the high baro table.

    There are gains to be had on these GEN5 trucks. If you look up posts by GHuggins, Higgs Boson, and Ben Charles.....lots of good learning to do.

  3. #3
    Thanks a bunch! I don't have the following available on my screen, "Driver demand" settings under Engine>Torque Management>Engine , Cam timing is at Engine>Airflow>Variable Camshaft>Intake Camshaft>. They are not there. I am using ver 3.6.6. I wonder why I don't have those functions. Certainly answers why I can't see cam timing! It's not there.

    The DFCO did the trick. Thanks! I will leave the "Throttle" setting alone. What do the numbers mean in the table on Engine>Torque Management>General>Mapped Gear? Would these be referencing the tables you mention that I can't see?

    Thanks Again . You already helped me out! I can tell you in an "off Road" situation, There is a lot of potential here. You know that when you add long tubes and watch the flow capability of this little motor. The compression is obvious in the exhaust tone. The ability to control the torque will make a change in winners in certain classes of durability type racing. The motor doesn't need much to go full tilt. Running open long tubes with no other changes other than removing catalyst warm up and cooling controls, adds a surprising amount of power. Especially from 4 to 6,000. The ECU just loves the flow. Leaning PE to 12.5 to 1 and the thing starts to run. I don't think ANY driver will ever love ETC. Man it is hated by that group! I hope I can find out how to get to the Maps you mention above. Maybe we can help the feel of the throttle without breaking the Trans.

  4. #4
    Advanced Tuner IARLLC's Avatar
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    Glad to hear of some improvements

    On the top/left click Edit>down to View>are you in Basic or Advanced? Maybe that will get you those tables.

    As for the Engine>Torque Management>General>Mapped Gear, I think the designations in Mapped Gear just dictate exactly what gear each of the columns in the Tip In Enable table (just to the left) control.

  5. #5
    Man do I feel feel dumb! I sure do have the tables now . I am sooo happy now. Thanks a ton. Added your other suggestions. Very nice. On the right track now. What a huge help you have been. I can't thank you enough.

  6. #6
    Advanced Tuner IARLLC's Avatar
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    That is great! Very glad to hear it. Enjoy!

  7. #7
    IARLLC, if your still out there I was wondering if you had any knowledge or thoughts about why the "Driver demand" settings table seems so arbitrary from the factory? The numbers are far from "smoothed". The camshaft timing is also a mystery to me. I understand the advance at the low to mid load. Emissions are reduced there. But why would the factory advance the cam at high RPM? This goes against what we have learned on the DYNO. Advancing the cam generally improves low to mid torque. Retarding it improves high end. The crossover is key. The factory WOT settings appear to continue to advance the cam more as RPM increases. I would expect to see neg numbers or, cam retard at high RPM. Typically on the DYNO if a lot of cam advance is needed the cam is too "big". I am pretty sure the 5.3 cam is not to "big".
    I truly aprechiate your input. Thanks.

  8. #8
    Advanced Tuner IARLLC's Avatar
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    Hi Robert,
    The Driver Demand? Good question. I think the engineers were arguing between fuel economy, shift strategy, acceleration, and smoothness....then the acceleration guy punched the smoothness guy in the mouth, the fuel economy guy hit the acceleration guy with a 2x4, then they just went home and left all of their opinions on the table Seriously, I think everybody appreciates smoothing out the DD table. I have a unique client that has his group of GEN5 Denalis drive closely together at higher speeds. When they moved up from their GEN4 Denalis to GEN5 back in 2015 several of the drivers complained about how hard it was to drive "in formation". And that group all had the 6 speed.... After mild smoothing of the DD tables they were very happy. Now they just got a group of 2017s with the 8 speed and the 2017 price went up....and no 2017 unlimited license available. I hope they don't take me out in the desert....

    Oh yeah, cam timing. You are correct about how it should be It actually is that way. Positive numbers represent cam retard. If I remember correctly the cam is advanced 8.5 degrees at rest (0)....so it idles 8.5 advanced. (Not counting the section I refer to as EGR over-retard in the low/mid cruise) the cam is gradually retarded as RPM rises starting around 3,000 on a GEN5 6.2. I am not sure exactly what the cam retard map looks like on a GEN5 5.3. I can tell you that on GEN4 and GEN5 I have had major improvements in responsiveness by making the high baro table look a bit more like the low baro table (in a general sense). I don't mean just cutting the low baro and pasting into the high. I actually log a lot of light throttle cruise to know exactly where on the map to leave alone then I blend out of the EGR over-retard from that level down. This raises cylinder pressure in those regions quite a lot so it is important to log and adjust variable cam spark afterwards. Some like to just 0 out the whole low RPM region and that is understandable but I try to leave the areas that are not hurting power alone. Of course this step won't gain you any full throttle power but it will make for more pleasant/responsive/predictable driving with little or no loss in fuel economy. As far as full throttle I expect that the tiny cam can use more retard up top (if it starts out advanced 8.5 (reads 0) and the top of the chart it is only retarded .5 degrees (reads 9)).....but I have not tested this so I cannot speak to it.

  9. #9
    I know those engineers! Ha ha.. I would guess you have a vehicle that can out run the Denalis.

    I fully understand your teaching on the cam timing. I have implemented your suggestions so far with great success. You are very generous! This will be a big help out of the gate for us. I will definitely save some time starting out in the right direction. I am logging data on a track environment nice long pulls. Its like having a rolling dyno hooked to the hitch. Logging is defiantly reducing dyno time. Gotta love these computers. This should make for a nice running stock class vehicle that will finish. As much as drivers hate the Torque Control,from my standpoint its awesome.

  10. #10
    Advanced Tuner IARLLC's Avatar
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    Yeah, these GEN5s have outstanding potential. One quick bit I have seen a few times on GEN5s....people often retard ignition timing to get away from KR like on previous models....and of course that is right if the cause of the KR is ignition timing....but we have seen times where retarding the timing made the KR worse. Something new every day right!? Cold Air Intake goes a long way on these in that regard. But I have seen that some have been able to reduce or get rid of KR on these with injector timing adjustments (mostly SOI table). GHuggins helps a lot of people on here. He really has the GEN5s figured out....especially in the injector timing department. As much as I want to I personally have not been willing to experiment (injection timing) on this particular client's fleet of XLs. They just bought a large group of 2017s....Maybe they will transition into them and give me a 2015 to play with for a while

  11. #11
    Per your suggestion, I am following posts by GHuggins, Higgs Boson, and Ben Charles. Very good stuff! I am also very cautious about any change that could effect durability. I have only altered timing in the cranking tables, IAT, PE/COT and VCT spark. Scarred to touch the main tables. I am wondering if the reduced EGR effect of altering cam timing will cause KR. I think the EGR effect goes a long way to reduce knock. Unfortunately, it kills a little power during those conditions. Off road I prefer to run without any EGR effect. I just am not sure I can without the motor complaining. And to further complicate, fuel usage is a factor. You can only carry so much. I hope my VCT spark correction prevents KR. Surviving 1000 miles of off road competition leaves little room for risk. On a limited budget here. I am afraid to "Melt the Mule"! Any sign of KR and I will take a look at what I did so far. I will follow you adventurers into the high end of tuning! Best left to the Pro's. Since you might get a "Mule to Melt", I will call you and arrange for your shop to take the tune that far.

  12. #12
    Advanced Tuner IARLLC's Avatar
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    Yes, reducing the EGR effect will increase cylinder pressure a lot.....but you just need to give the correct amount of ignition lead for that amount of cylinder pressure. I use the Engine>Spark>Advance>Variable Cam>Spark table for this, but there may be a better way.

    I don't think that the EGR effect helps fuel economy much but I only modify the tables just barely above light throttle cruising...so it should not take away much even so.

    As I mentioned, the top end numbers won't change from this but the amount of time wasted coming on and off the throttle and wishing the trans would do what you want (sooner) is reduced quite a bit. I personally think it saves gas for certain types of drivers and terrains where the weak EGR effect makes for a lot more downshiting....

    On another issue you brought up. Spark advance! GHuggins has a client with a GEN5 6.2 work truck running 87 octane and getting great gas mileage with higher than factory ignition advance! More power (especially down low), better fuel economy, and and and. It might require some of his special knowledge of injector timing to get such results though. My client's fleet of Denalis have an unlimited supply of 98 octane....so I can give them a bit more ignition lead without concerns....but I would rather do it GHuggin's way and really optimize them.

  13. #13
    I am on track with you on the cam timing. I applied your thoughts and halved or better most of the retard in the EGR zone. I zeroed the VCT to be safe and logged it on some pulls "in the range". No KR even when "squeezing in". 90deg outside 54% humidity 500 feet above sea level. IAT timing adds are zero to 122 deg. PE is reduced to Phi 1.1. & Enable pedal is reduced to 35%. PE delay is 800 rpm. All Baro Pres Cam tables are modified to have pre-3000 rpm retard removed (0). I think with this tune it is safe (I did not log any KR on pulls) to sneak away at advancing the timing. I can tell you however, the increase in performance with open headers and cold air intake is substantial. There is no mistake in the performance across the board. The Driver pedal feel feedback is good. Very good. Your statements on Trans shifts are spot on. Much faster. Very smooth. Just feels good! With open headers the changes in sound are obvious. The nasty sounds of excessive ignition retard are gone. The EGR camshaft timing reduction drone during cruise/light load is gone. Sounds fast Ha ha! I cannot take away from the DD smoothing either. This total combination made Drivers note a "Steady Pedal" right away. A rookie thought we took out the drive by wire! As you say above, I also noticed immediately it would pull more without downshifting. So I checked the log for the effect on manifold vacuum. Some sweet Baro increases right where you would expect. It also likes to stay in the gears as you suspected. Much less low throttle downshifting. The ECM/PCM seems to like the vacuum.

    You Probably have seen these, some good info on what the O.E's are up to with VVT and Spark Timing.
    http://www.j-mst.org/on_line/admin/f...2254-2262_.pdf
    http://www.sciencedirect.com/science...74667015399341

    I see what your saying on the "GHuggins way". I am reading some more info on that right now. I am sure that the tune I have now will perform well on the dyno and easily compare to some of the other stock class trucks I am seeing. I am comfortable nothing is in the durability danger zone... yet.

  14. #14

    2015 gmc 5.3

    IARLLC, The tune and the log file. The log file is a short run around the course with 2 good full power runs through the gears to 80 or 90 mph. It is the tune jimmymod7. As the log shows I can't get to the 25 deg of timing. In the tune jimmymod8 I have the TM Peak Engine Torque Maxed, the Humidity Spark Multiplier zeroed, the VCP Spark cam factor zeroed, and the VCP Spark multiplier zeroed. However, I haven't uploaded or logged that tune yet. I would like to wait till you look it over. I wonder if one of those things are what is keeping me from getting the full demanded 25 deg of timing.

    Tanks a ton for looking this over IARLLC, your advice is trusted and proven.
    Bob
    Last edited by Robert C Morgillo; 07-24-2017 at 10:47 AM.

  15. #15
    Advanced Tuner IARLLC's Avatar
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    Hi Bob,
    Sorry for the delay. Chasing issues on a friend's Suburban all day.

    For your main question (not getting more than 22 degrees even though asking for 25?) I wonder about "Max torque timing". I usually don't mess with it but since you zerod the adder tables it makes me wonder how much the GEN5 ECM depends on advice from the Max torque timing table. I bet GHuggins and the other experts know. Hopefully they can chime in with some wisdom on this.

    I will have a better look at the tune tomorrow but here are some quick notes:
    Some codes will force reduced power. Some will force a speed limit.
    Since you are running open exhaust
    Under Engine Diagnostics>DTC I would:
    set P0420 to no error reported
    P0430 same
    Under Engine Diagnostics>Exhaust I would:
    disable cat test

    Might be worth it to go over to Speedometer>Limiter and raise some of the code related limits for your off-road situation

    Now that I see your Stoich AFR is as 14.1 is see how PE EQ 1.1 is getting you enough fuel. When you first mentioned your PE AFR the other day I could not believe it was getting enough but based on your 14.1 Stoich, your 1.1 PE EQ should ends up around 12.8 AFR if your MAF is tuned in well.

    I hope some of that made sense. Just passed 3:30AM here. Lots to do before we head back to the States in a few weeks.
    Jeff

  16. #16
    Awesome Jeff! I get it fully. I am putting your suggestions into mod8. You have a lucky friend with the Suburban. I am going to wait till you can look it over to your liking. And maybe GHuggins is looking in, and can drop a comment. I wish Greg Banish (https://www.amazon.com/Greg-Banish/e/B001JOVJT2) would put out something for reading on the GenV. There is not a lot out there. I am lucky for some connection to the O.E's. I can tell you they are not as familiar as you are with "Hot Rodding" the ECM PCM's. The GenV has a lot of potential and quite a few things that can mess you up quick! Right now by far this site is the best place to follow the GM GenV. You in particular are on the "cutting edge" of this for sure. This site has a fantastic resource in you.

    Since the tune is out there. If anyone downloads it, it must be noted:
    This is an open exhaust , long, large tube open header system with long balance tubes and Cold air intake. It would be a bad idea to upload this tune to a vehicle that is not an exact duplicate. Many log runs on a controlled environment has been used so far. This tune still needs to be Dyno proven for off road use. It is quite possible this tune has way to much advance and, is far to lean for an On Highway vehicle. CAT temp could be dangerous.
    Last edited by Robert C Morgillo; 07-23-2017 at 09:11 AM.

  17. #17
    Advanced Tuner IARLLC's Avatar
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    Hi Bob,
    Thanks for the kind words. There are a lot of great guys on here that know much more than I do. They have made it into a great place for us to learn.

    Not sure because I was so tired last night, maybe I PMd you about the log. I don't see knock retard in the channels that are being logged. I seriously doubt that detonation is your issue at this point but logging KR will be really import as you start to get a bit more ignition timing added in. It might also be interesting to add other types of timing retard to the log to see exactly what all is affecting your timing. Maybe KR (doubt it). Of course some shift torque management. Maybe some Knock Learn. Maybe some Burst Knock Retard (likely). Or maybe some other kind of TM. At any rate logging these for a few runs might tell you exactly why you are not getting the timing you suggest in the High Octane table.

    As it sits, TM is taking your timing down to -22 during some shifts. Which is a bit low but fine as long as you get through the shift fairly quickly. Most racing situations call for quick shifts but not so harsh that you lose traction. 4:49.57-4:50.06 shows some interesting stuff. WOT timing 22-23 degrees (2-3 lower than hoped for). WOT shifts at 4500 and 5000 rpm (800-1000 rpm lower than likely best). Commanded AFR of 13.3 at WOT (.5 leaner than I humbly suggest). As the timing is very steady under load I am sure it is not KR that is keeping you down a few degrees. It is possible (if it is that lean) that it has learned to expect 2 degrees of detonation and as such "Knock Learn" is applying what it has learned to expect.

    At any rate, the cool news is that this thing will be even faster when all this is sorted and I am sure you can do it

  18. #18
    Yes I agree with you on the PE ratio. I will try to hit closer to 12.2 afr. 13.3 is a nice number for a quick Dyno pull that's about it! In fact you can see it "heat the water" at the top of the WOT run. No KR is a testament to the fuel I had in it. I think on a longer pull it would have started to detonate. I do not know how to reduce the timing retard during shifts. Any Ideas? Good eye on the shift rpm! Random short shifts? Then moments later n the next full throttle pull it shifts them all at 5600. I wonder if anyone else might have a thought on that phenomenon. It must be some form of TM. I will make these changes and log it. I'll let you know. Good luck on your trip.

    UPDATE:
    Just logged Mod8. Wow. I would say this is getting real good. Files below. New jimmy1mod8 file with all the above changes. Hitting the timing now! The clock on the 1/8th mile shows it is definitely fastest with mod8. Something strange however. I changed the PE Eq ratio to 1.16 from the 1.10. At 1.10 the logged WOT Eq was .909 / 12.8 afr @ 14.1 Stioch. The new log shows the 1.16 Eq went to 1.000! Way lean to 14.1 afr @ 14.1 Stioch. Not sure what to think of that. It ran good no KR heard or logged. I wonder if it is the PE knock enrichment Eq. I see the O.E setting is 1.000. Is it using that map during PE if it detects knock? It is running like it's going super nova. Now there is a lot of WOT fuel trimming going on. There was very little before.

    I think I see the problem. It is in a CL fault. It looks like it defaults to 1.000 Eq when it is in fault. Wow that's not good. I'll try and find that fault. One of my settings in mod 8. I think I know what it might be.

    Update:
    Maxing out "Torque Management Peak> Engine Torque" Causes the ECM to Fault into a 1.000 Eq. The log shows a CL fault at WOT. Changing it back to O.E. Settings and it reads "OL..Accel" which I think it should, I now have returned PE enrichment control.

    The interesting thing, the Engine Diagnostics Catalyst Test that you had me disable appears to be the cause of the timing pull problem I was having. Nice catch! Lots of timing now.
    Last edited by Robert C Morgillo; 07-24-2017 at 07:31 PM. Reason: Updates

  19. #19
    Advanced Tuner IARLLC's Avatar
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    I think I found it Bob. In Engine>Torque Management>General>Torque Limit vs. RPM> Peak Torque the whole table was maxed. I am not sure but I think the system uses that table to guestimate how much you are producing in any given situation...so if you don't get Power Enrichment until you are producing over 60% of 6042 lbs-ft...... So anyway, you could put that table back to stock and give it a quick run to see if PE comes back on.

    Now that you are getting 25+ degrees I think you will see more power today. Looks like it might give you even 27 or so degrees today with the bit of added fuel in PE, now that you sorted that issue with the humidity multiplier. Looking forward to the results!

  20. #20
    Jeff, we were working at the same time! Yup for sure you can't just max that table. That was a suggestion I read on the forum for the timing pull problem. Now we know. PE is a sweet .893 (still a little leaner than you like I think). Getting 26 deg of timing now. No KR. Man this thing is running well now. I think it's Dyno time. I will log a few good long Dyno pulls. I think this tune is a nice start.

    Interesting thing it was not the Humidity tables. I did leave the Humidity Spark Adder Dry zeroed. I returned the other Humidity related tables to the O.E. tables. I had zeroed the Humidity Dry in Mod6. It was in the mod7 tune when I tried to get more timing and could not get it, the problem was noticed. The change that fixed it was the Engine Diagnostics Catalyst Test. If you look my Calibration Details for that Mod8 tune, it is the only change I really made over the Mod7 tune. Turn it back on and boom... timing retard. I do notice it runs in CL fault most of the time since I disabled the rear O2's (Bank 1 and 2 sensor 2's). It is always pending the heater circuit codes.
    Attachment 71694
    As soon as I clear the codes you can hear it jump out of fault and the fault clears for a few seconds, then you can hear it jump back into fault. Any ideas?
    Last edited by Robert C Morgillo; 07-24-2017 at 04:44 PM.