Creating my own trans tune

[TrentNell]

Thats a lot of crap. People know....but its all "sekret skwirrrl".....because theres a buck to be made here. Its pointless. I'll let you know when I fry my trans from trying.

Well, in looking at the stock tune, it looks like the TCM tries to bring torque back to stock levels. (~500ft/lbs) Trying to drop >500ft/lbs in a blink of an eye is IMO just not feasible. Would upping the defuel request to around 750 be a more reasonable drop? This is assuming fuel would be removed, but not completely back to stock levels?

Tom , I told you the honest answer , whether you choose to accept it is up to you , I have spent aloooot of hours trying different stuff here , and there are at least 8 different tables that can screw up your efforts and all have to be in sync , and would need different tweeks depending on how the ECM was tunned originally . When you are looking at those torque #'s remember the truck has no idea how much torque its making , we tell it what torque is beeing made per X amount of MM3 and RPM in the base torque table . In all honesty you will fry your trans one day just like the rest of us , when your running hard stuff will wear faster and stuff WILL break , its not if but when . For me to answer your question would take me 3 pages of typing and it would only hold true if you were running an identical ECM tune for what i have tested .

 

[GMC_2002_Dmax]

I run a stock 2001 TCM tune, Cougar281 has the file and it is available at the DP in the library.

The key to good shift is in the ecm tuning.

It is no simpler than that.

No secret squirrel stuff, just time and changes to get it right.

 

[sweetdiesel]

Tony is this the TCM your refering to?


I agrree with what Trent and Tony posted

 

[[email protected]]

Looking at a stock LLY:

The base torque indicates 539fl.lbs. at 100mm3 and 3200rpms

It decides to shift right here. So it looks at TLIQ and see it should limit fueling to 91mm3. Dropping pulse from 1526us to about 1360us about a -10% reduction in fueling only at 3200rpms though. As the trans shifts and rpms gets lower it looks like the TLIQ tables still commands somewhere around 90mm3.

I havent run a stock tune in a long time, but I don't want to re learn my trans. It would be nice to know how much a stock tune does deufuel though.

I think there is a table missing that tells something about how much torque in a percentage or something it should reduce when shifting. Becuase I don't see any table that tells DMAX DMA torque to come down during a shift? The base torque only tells what torque the engine makes a a certain fuel and rpm.

So what tells the ecm how much torque it should reduce. It looks like the ecm knows what fueling should be at to make torque a certain value, but it dosent know what torque it should try to make when the trans is shifting.

 

[racinmike77]

you can write the TCM however you want but it will always refer to the fuel tables in the ECM for defuel.

 

[Mike L.]

Shift quality in the Alli is dependent on many things. All of them are in the ECM. I have been doing a lot of testing on my truck and found that a slightly restricted fuel line will cause a crappy slipping shift. Slightly loose IC hose will cause the same. Loose bolts at the EGR will cause the same. Trans shifts will deteriorate as the fuel level in the tank get lower. Trans shifts will start to get mushy when the fuel temps get over 150F and get worse the hotter the fuel gets. Trans shifts will do funny things when your air filter begins to get dirty. I have documented all of this because I am trying to hunt down a problem in my truck.
This is why I have to try and overcome these problems mechanicaly in the trans because there are no answers in the TCM. There are answers to an extent in the fueling tables and they work. Your tuner should be able to fix it or steal someone elses tune and fix it.

 

[Jasondt2001]

I think there is a table missing that tells something about how much torque in a percentage or something it should reduce when shifting. Becuase I don't see any table that tells DMAX DMA torque to come down during a shift? The base torque only tells what torque the engine makes a a certain fuel and rpm.

In logging mine uses: "Requested Torque Reduction" shown as: REQTRQR

You'll obviously see it right before the shift, on my stock tune at about 3/4 throttle it would show on average 25lbs reduction per shift at that throttle.

 

[[email protected]]

Ive seen what you are talking about, but you have to be logging the tcm to see it. So I guess there is a table in the TCM that tells the tcm how much defuel it should ask for to the ecm.

 

[sweetdiesel]

Looking at a stock LLY:

The base torque indicates 539fl.lbs. at 100mm3 and 3200rpms

It decides to shift right here. So it looks at TLIQ and see it should limit fueling to 91mm3. Dropping pulse from 1526us to about 1360us about a -10% reduction in fueling only at 3200rpms though. As the trans shifts and rpms gets lower it looks like the TLIQ tables still commands somewhere around 90mm3.

I havent run a stock tune in a long time, but I don't want to re learn my trans. It would be nice to know how much a stock tune does deufuel though.

I think there is a table missing that tells something about how much torque in a percentage or something it should reduce when shifting. Becuase I don't see any table that tells DMAX DMA torque to come down during a shift? The base torque only tells what torque the engine makes a a certain fuel and rpm.

So what tells the ecm how much torque it should reduce. It looks like the ecm knows what fueling should be at to make torque a certain value, but it dosent know what torque it should try to make when the trans is shifting.

That is why you adjust base TQ, Am I missing something here?

 

[sweetdiesel]

you can write the TCM however you want but it will always refer to the fuel tables in the ECM for defuel.

So you can remove defuel in the trans and be safe? Because the ECM will over ride?

Have you tried this?

 

[GMC_2002_Dmax]

That is why you adjust base TQ, Am I missing something here?

Nope...........

So you can remove defuel in the trans and be safe? Because the ECM will over ride?

Have you tried this?

Others have, that's why MIKE L, DIPPER, and other builders have so much business now...........:rofl:

The answer is simple, it takes time to figure it out and a complete understanding of what happens and why.

Its easier than most think if you know what to "change" and what to "leave alone"

 

[[email protected]]

It would be nice if you could adjust base torque to what you think it is but on LLYs and LB7s the max is like 750 something ft.lbs.

But If your pulsewidth table is changed a lot different from stock I would think it would mess it up. I guess this is why everyone tricks it and just uses TLIQ to control defuel.

 

[sweetdiesel]

It would be nice if you could adjust base torque to what you think it is but on LLYs and LB7s the max is like 750 something ft.lbs.

But If your pulsewidth table is changed a lot different from stock I would think it would mess it up. I guess this is why everyone tricks it and just uses TLIQ to control defuel.

Have you ever logged the truck and looked at base tq when you shift?

No matter what combination of PW and TLIQ you can still change the way it shifts It might just take you longer to get it perfect.

Road Runner helps

You are logging the correct pid, And looking at the correct table?

 

[TheBac]

Ok, heres another tack to understand this....

Can someone make a "flowchart" that describes what tables are used at a shift? That way Im not asking what values to input, which is someone's work....but where to look in what order. That way I can start to understand how the tables interact.


My limited understanding is as followed:

Trans wants to shift, so it

1) asks ECM for defuel via tables D5194 thru D5197, with D5196 governing the max torque value the trans wants to see during the shift, and D5194/95 setting the parameters for % reduction.

2) ECM looks at TLIQ (B0741) for fuel limiting (peak?) amounts (mm3)

3) ECM looks at Base Torque (B1102), and using TLIQ value and engine RPM, tries to limit torque to the value at that box --UNLESS --

4) said value is HIGHER than Peak Torque vs RPM (B1106), in which case PT-RPM takes precedence.

Is that correct?


Man, I knew I should have gone to Nick's tuning class down in Marshall a few months ago.

 

[[email protected]]

So where is the table in the tcm (or ecm) telling the ecm what torque value to limit too based on some variable (tp?) and a percentage of torque to reduce?

Like maybe a x axis of rpms and a y axis in a percentage of torque reduction based on current torque?

 

[GMC_2002_Dmax]

Ok, heres another tack to understand this....

Can someone make a "flowchart" that describes what tables are used at a shift? That way Im not asking what values to input, which is someone's work....but where to look in what order. That way I can start to understand how the tables interact.


My limited understanding is as followed:

Trans wants to shift, so it

1) asks ECM for defuel via tables D5194 thru D5197, with D5196 governing the max torque value the trans wants to see for Max torque, and D5194/95 setting the parameters for % reduction.

2) ECM looks at TLIQ (B0741) for fuel limiting (peak?) amounts (mm3)

3) ECM looks at Base Torque (B1102), and using TLIQ value and engine RPM, tries to limit torque to the value at that box --UNLESS --

4) said value is HIGHER than Peak Torque vs RPM (B1106), in which case PT-RPM takes precedence.

Is that correct?


Man, I knew I should have gone to Nick's tuning class down in Marshall a few months ago.

Please do not take this the wrong way, but wasn't it Nick who supplied you with the ecm and tcm tuning and was he not the one who sent you disabled tcm defuel tunes ??

If you are running his tunes and are asking to get them improved why isn't he fixing them for you ??? Or are you looking to fine tune what he sent you yourself ???

Or are you not using him anymore ??

 

[TheBac]

So where is the table in the tcm (or ecm) telling the ecm what torque value to limit too based on some variable (tp?) and a percentage of torque to reduce?

Like maybe a x axis of rpms and a y axis in a percentage of torque reduction based on current torque?

I think you're talking about D5196 in the TCM, Torque Limits?


Im just afraid Im going to know just enough to destroy something this weekend...

 

[The Neens]

Maybe start with an ECM/TCM combo that you know works well, then delete 1st gear based on what advice has been posted here...That way you're not making too many changes at once...Seems like it's hard to troubleshoot problems after trying a bunch of new things...

 

[sweetdiesel]

you guys are making this WAY more complicated! I am simply confused by your posts?

There is enough info allready posted in this thread ,that if you would actually take the time to read that your trans would be shfting perfect
If you want to do it yourself then thats great,However you seem to want all the answers that cant be given? Your TUNE is diifenrent than mine.Me telling you what to do is pointless

What is it that your actually trying to do? Have you looked at the logs from the track and said HEY my trucks TCM needs modifacations?

There is no squirls.....And FU for even saying that We are trying to help you understand.



AFAIC ask Nick He is your tuner,he should know!

 

[TheBac]

Maybe start with an ECM/TCM combo that you know works well, then delete 1st gear based on what advice has been posted here...That way you're not making too many changes at once...Seems like it's hard to troubleshoot problems after trying a bunch of new things...

Only trouble with that idea, Chris is that the combo that worked best for my truck included the defuel-disabled TCM tune that wrecked Zero's trans.