LBZ: Need Advice, New to Tuning
- Thread starter macanic21
- Start date
You have to remember that the throttle also determines the gear you are in. At a higher throttle % the gear should drop (relative to the RPM) so the engine will rev up. It is a way of keeping everything safe and EGTs in check, etc. Ultimately you are still producing more HP at a higher RPM and less mm3 per injection
You can see it in the 040 log at frame 486. You can see the converter slip and RPM spike but there is no change in TCC %
Also frame 2742 of the other log.
They are 265/75r16 which comes out to 31.7" tall. Not sure why that would be, I didn't change it...
It looks like the transmission is seeing it as TCC slip but I wonder if it is actually 4th gear clutch slip. I'm wondering if the trans actually has a way to differentiate between the two. It would need more than engine RPM and output shaft speed sensors.
What other parameters can I log to figure this out? Can I log 4th apply pressure?
Also frame 2742 of the other log.
They are 265/75r16 which comes out to 31.7" tall. Not sure why that would be, I didn't change it...
It looks like the transmission is seeing it as TCC slip but I wonder if it is actually 4th gear clutch slip. I'm wondering if the trans actually has a way to differentiate between the two. It would need more than engine RPM and output shaft speed sensors.
What other parameters can I log to figure this out? Can I log 4th apply pressure?
Here are 2 more logs. You can see at frame 2252 in 044 that I got a spike in TCC%. I think this was because I had the 3rd gear lockup still set at 47MPH. It could have also been because the tires spun. I set that up to 60 since I'm going for no lockup in 3rd right now.
I updated some shift points after these logs and also the revolutions/km and attached it. I wanted to push 5th out further, and bring in 4th lockup sooner at higher throttle positions. You can see that at the end of the log where it drops the RPM down to 2k when it hits 5th.
Any ideas why MPH isn't logging?
I updated some shift points after these logs and also the revolutions/km and attached it. I wanted to push 5th out further, and bring in 4th lockup sooner at higher throttle positions. You can see that at the end of the log where it drops the RPM down to 2k when it hits 5th.
Any ideas why MPH isn't logging?
Yes
put 396 in H0136 of our ECM tune. don't touch the tire size/speedo in the TCM tune, leave it stock
try updating your torque table (D5196) in your TCM tune to match your ECM. you can also copy and paste all the values from the attached text file as I have already extracted the information for you
There are many, possiblity hundreds of tables in the TCM that we dont have access to that those will effect. Changing them will cause unknown alterations to these other tables and make the transmission do weird things
Also, stock, they don't match the ECM. It seems GM also had no reason to make them match or at least didn't spend the time to make everything line up. You may notice that not even the MPH in the shift tables matches real world.
This is one of the reasons not to mess around in the TCM unless you know exactly what you are doing and if you have to, do it in baby steps
Also, stock, they don't match the ECM. It seems GM also had no reason to make them match or at least didn't spend the time to make everything line up. You may notice that not even the MPH in the shift tables matches real world.
This is one of the reasons not to mess around in the TCM unless you know exactly what you are doing and if you have to, do it in baby steps
You can see it happen again at frame 1608 of the 049 log. Interestingly, it locked up fine twice before that when TPS was 0%. I'm interested to see if anyone can figure this out but I might have to go back to stock and play with only the lockup points to see if that it simply refuses to lock nicely in 4th when cold.
It looks like my issue with not getting out to 120mm3 is resolved. It was an issue with not having all the desired torque tables matching up. Log 050.
It looks like my issue with not getting out to 120mm3 is resolved. It was an issue with not having all the desired torque tables matching up. Log 050.
don't see any issues with Log 049 and lock up
in Log 050, it does appear that it may be a bit laggy when you press on the accelerator. boost and RPM seem to come up real slow. this may be due to your vane tables but I bet it is more to do with your TCM tune and not down shifting as it should. normally when one presses down hard on the throttle the transmission should drop down a gear or at least unlock the converter to allow the RPMs to come up, boost to be built and then the engine can make some HP
what I see around frame 6870 on log 050 is you press the throttle from about 5% all the way to 100% and it takes about two and a half seconds for the RPMs to go from 1000 to 3000. this should happen in one or less seconds.
in Log 050, it does appear that it may be a bit laggy when you press on the accelerator. boost and RPM seem to come up real slow. this may be due to your vane tables but I bet it is more to do with your TCM tune and not down shifting as it should. normally when one presses down hard on the throttle the transmission should drop down a gear or at least unlock the converter to allow the RPMs to come up, boost to be built and then the engine can make some HP
what I see around frame 6870 on log 050 is you press the throttle from about 5% all the way to 100% and it takes about two and a half seconds for the RPMs to go from 1000 to 3000. this should happen in one or less seconds.
hey guys just wanted to write in and say hello<< I'm new to both an lmm and efi live in order for me to get some the simple info I need I would be writing to many words to read and it would simply bore u guys,,,
was wondering if any of u guys would be kind enough to answer some my questions over the phone as kind of a walk through look at ask question type thing<< I'm not asking for ur secrets just some simple understanding of some of the things and what they do,, help would be greatly greatly appreciated,,,pls let me know either email tommyashley@icloud or by phone preferably 606>>872>>>7086,,
was wondering if any of u guys would be kind enough to answer some my questions over the phone as kind of a walk through look at ask question type thing<< I'm not asking for ur secrets just some simple understanding of some of the things and what they do,, help would be greatly greatly appreciated,,,pls let me know either email tommyashley@icloud or by phone preferably 606>>872>>>7086,,
I fought this on mine for a long time. Never ever did get it to where I was really happy with it but It was manageable.
You guys will probably think I'm nuts but I really don't mind the lag to a point. I do need to make some downshifts happen sooner though for my tastes. I do have a specific goal in mind for this if you guys are interested. The jury is still out.
I went back to the stock TCM tune, modified nothing but the TCC Tables. I added my 4th gear curves and pushed the 5th and 6th down so it would stay locked, enabled locked shifting and had the same exact problem. At this point I'm calling it something in the stock tuning but I'm out of ideas again on what to try.
I went back to the stock TCM tune, modified nothing but the TCC Tables. I added my 4th gear curves and pushed the 5th and 6th down so it would stay locked, enabled locked shifting and had the same exact problem. At this point I'm calling it something in the stock tuning but I'm out of ideas again on what to try.