Is there anything that can be done in the PROM for the TCC functions? Not sure if lowering the speed will help cure the following problem.

Any suggestions?

Here is a copy of the problem.

You know the pin connector that plugs in on the top side of the Auto Box.

Well that has to be left unplugged, as when the last owner had the boxed worked on he got a larger stall and you cant use the Lock up feature.

If I plug that connector in when I hit about 80 kms you can fell the converter locking and unlocking all the time. So I have to leave it off. Everything else works, like the overdrive gear but just the final lock up has to be left off.

 

There are a bunch of settings for the TCC.
RBob has a good writeup here that describes the operation and variables.
https://www.thirdgen.org/forums/diy-...ad-vs-mph.html
Once you get a feel for what is wrong then you can make some changes and experiment with them.
Side note: If this is an $8D application, There is a flag to set if the function is "speed" or "RPM" based.
Might want to try and play with that as well.

 

I might try and copy the tables from my 8D to my mates 6E for the TCC. His problem is

I have been told when you have an aftermarket stall installed it is normal to have to un-plug it because they normally don't lock up correctly anymore. (Just what I have been told anyway)

When I tried it plugged in, once it locked up and you took your foot off the pedal the car would start clucking back and forth in and out of lock up, so I had to remove it.

And looking at the TCC table the lock and unlock is controlled by the tps % vs speed. So not sure why he is getting the problem.

 

I noticed the flag for a while now, but where are the TCC constants for RPM based operation? all the thresholds are MPH.. ??

-- Joe

 

It uses the same lock/unlock TPS% lookup tables. It is just that the table scale is now RPM instead of MPH.

RBob.

 

Thanks! I was curious if it used the same table, or whatnot.

You have a screenshot how the constant should look in tunercat? Tunercat's tdf editor is cryptic to me. Tunercat only has constants for lock/unlock based on MPH.

-- Joe

 

You would be adjusting the "TPS% load value", not the speed or RPM.
They are scaled constants.

Why is it called "load" value anyway?
I see no reference to map or anything except for what looks like a filtered value Vs the current value.
Is this a TPS movement "transition" load amount?

 

Make a new table(s) that is identical to the MPH table. Then change the axis values to the proper RPM values.

RBob.

 

It is sorta' like a load. Think of the two values together: TPS% and MPH (or RPM). At this MPH and this much TPS%, the engine will have x amount of load on it. Other then that it is just what the guy who did the hac called it.

The TPS% from the table is compared to the current throttle position.

RBob.

 

I'm starting to like the way aftermarket does it, again.

Guess I need to read the hac over when I get a chance. I thought the TCC stuff was straight forward.. Shame on me for building an automatic car, after all these years of running sticks.

-- Joe

 

For a good write up on GM TCC logic see this post:

https://www.thirdgen.org/forums/diy-...ad-vs-mph.html

What type of methodology does the aftermarket use for TCC control?

RBob.

 

Pretty simple. lock at rpm, unlock at rpm.

Seems most everyone I talk to locks the converter at peak torque, so you get slipage until peak then lock until shift.

Kinda had hoped to get the same logic out of $8D. guess I have to read more

-- Joe

 

That's fine for WOT or highway use.
But city driving with the converter locked at low speed in 3rd or 4th would cause a problem. What about a small hill. Also to get the MPG benefits, the converter needs to lock early.