HELP TCC standalone controller (I'm designing) for 200-4R or 700-R4

rfpowerdude

G-Body Guru
Jul 15, 2013
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Palm Bay, Fla
I know I put "Help" as the heading, but it is not I who needs help, it is I who is offering help by way of possibly getting a standalone TCC controller off the ground. I need something for myself so I am designing one from scratch. I am doing two versions, one that is all analog in nature and one that uses a PIC microcontroller. I am doing the analog one first to get something quickly since I am an RF/Analog EE and analog is totally in my wheelhouse. The PIC micro thing will cause me to have to relearn C coding which I haven't done since it was required of me over 30 years ago in college.

So, with all of that said, would anyone be interested in having something like this? It would use a Digital Dakota inline speed sensor (so you can keep the speedo cable for stock speedo) and the stock MAP sensor. The other two inputs would be the brake and 4th gear switch. This allows for the removal of the ECM, but enables TCC automatic control. It would mimic the ECM functionality in this regard. It would not lock until the folling conditions are met: 4th gear, no brake, and MAP and speed over the threshold. Any unlock condition would unlock immediatley and then once the relock conditions are met, an adjustable relock delay would re-engage the TCC.

Whattay'all think?
 
HECK YES! But - could/would this work for the TH350C as well? It locks in 3rd gear but I assume it's functionally the same otherwise.
 
TCI makes a TCC lock up kit #890-376600 for $160. I've had mine since the early 90's and it works great. It actually works a little better than the factory control. I did need to install a vacuum reservoir with a 3 port check valve to make it apply and release smoother although it worked fine the way they had you install it. I'll try to post pictures/vacuum diagram and check valve number either tonight or tomorrow. I think back then it was $50!
 
I love the idea, and it makes perfect sense for anyone running carburetor, non EFI EMS.

I've been running the TCC on my 4L60 through a custom Output on Holley EFI and it took awhile to tweak all the settings just right, but since it's been dialed in I wouldn't change it for the OEM control, or any of the stand alone kits, but that's just me.

Real good call on the delay for engage/re-engagement, when Holley added a timer to IO settings it made a huge difference in drivability. I used to hate if all the switch/sensor params were met, but I wasn't really going to be in 4th but for a brief few secs, it would immediately lock up and lug the engine. This was like when slowly climbing an incline or onramp where I didn't want to have it lockup until I was at a steady cruising speed for about 5-7 secs. I tried to tune it with MAP and SPEED, even TPS but it never quite was to my liking, and the delay pretty much solved it.

My only advice (if you want any) would be:

1 - Allow for the 4th gear switch input to be N.O., or N.C. since not all trans came with one or the other in my experience. It would save having to swap it out unnecessarily for the install. In the Holley Input trigger (see below) you can set this by just used "Enabled" or "Disabled" depending on what's in the trans.

2 - Include CTS (Coolant Temp) as as input, or just a fixed min. engine temperature (ie; 120 deg F) before it can lockup.

Sounds like a great little project, good luck with it!!

Here's the params I use on the Holley EFI for mine (every config, gears, etc will differ); RPM might be something to consider as well, but you can probably get by without it. The hard thing to tune imho is those cases where it get's into a little goofiness and the lockup shuttles/surges on/off repeatedly. The delay helps with that a lot as well in my experience.

Notice the "AND" logic between the Switch and Sensor Input triggers, it can also be set "OR" if so desired just an FYI.

1726597710523.png


1726597750178.png
 
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Thanks for all of the input so far! Definitely love everyone's thoughts and input since I hate designing in a vacuum.

brrian
Yes, it would work for a TH350, you could just disable the 4th gear switch. If anyone wants to disable the 4th gear switch input, anyone can do so.

86 Salon
Does the TCI lockup kit include speed sensing? Vacuum input?

BuickOldsPontiac
I will share as I go along with the development!

383_StealthRam
These inputs would all be AND'ed together. The 4th gear switch can be left disconnected to make the circuit ignore that input. In a 200-4R, the switch in the trans is open when in 4th gear and grounded when in any other gear. Pulling that input to ground will make the circuit behave as if the car never got into 4th gear. Leave disconnected to be ignored.

As for coolant temp, I'd hate to have to require everyone to use ANOTHER standalone coolant temp sensor/switch. Maybe I could just make like a 3 to 5 minute (or TBD) delay after ignition power on to allow for warmup?

88hurstolds
Yes, I am using a factory MAP sensor. I charted vacuum vs. voltage output with 5V supplied to the sensor. And yes, you could make it ignore that input by tying that input to ground. That would make the circuit behave like there is max vacuum at all times. Then the circuit would only look at BRAKE, SPEED and 4th gear switch.

Keep the comments coming! I have a completed schematic that I have simulated parts of in LTSpice. I ordered all the parts and they should be here by Thursday. I'll breadboard it up after that and start testing on the bench with simulated inputs.
 
Thanks for all of the input so far! Definitely love everyone's thoughts and input since I hate designing in a vacuum.

brrian
Yes, it would work for a TH350, you could just disable the 4th gear switch. If anyone wants to disable the 4th gear switch input, anyone can do so.

86 Salon
Does the TCI lockup kit include speed sensing? Vacuum input?

BuickOldsPontiac
I will share as I go along with the development!

383_StealthRam
These inputs would all be AND'ed together. The 4th gear switch can be left disconnected to make the circuit ignore that input. In a 200-4R, the switch in the trans is open when in 4th gear and grounded when in any other gear. Pulling that input to ground will make the circuit behave as if the car never got into 4th gear. Leave disconnected to be ignored.

As for coolant temp, I'd hate to have to require everyone to use ANOTHER standalone coolant temp sensor/switch. Maybe I could just make like a 3 to 5 minute (or TBD) delay after ignition power on to allow for warmup?

88hurstolds
Yes, I am using a factory MAP sensor. I charted vacuum vs. voltage output with 5V supplied to the sensor. And yes, you could make it ignore that input by tying that input to ground. That would make the circuit behave like there is max vacuum at all times. Then the circuit would only look at BRAKE, SPEED and 4th gear switch.

Keep the comments coming! I have a completed schematic that I have simulated parts of in LTSpice. I ordered all the parts and they should be here by Thursday. I'll breadboard it up after that and start testing on the bench with simulated inputs.
Thanks for all of the input so far! Definitely love everyone's thoughts and input since I hate designing in a vacuum.

brrian
Yes, it would work for a TH350, you could just disable the 4th gear switch. If anyone wants to disable the 4th gear switch input, anyone can do so.

86 Salon
Does the TCI lockup kit include speed sensing? Vacuum input?

BuickOldsPontiac
I will share as I go along with the development!

383_StealthRam
These inputs would all be AND'ed together. The 4th gear switch can be left disconnected to make the circuit ignore that input. In a 200-4R, the switch in the trans is open when in 4th gear and grounded when in any other gear. Pulling that input to ground will make the circuit behave as if the car never got into 4th gear. Leave disconnected to be ignored.

As for coolant temp, I'd hate to have to require everyone to use ANOTHER standalone coolant temp sensor/switch. Maybe I could just make like a 3 to 5 minute (or TBD) delay after ignition power on to allow for warmup?

88hurstolds
Yes, I am using a factory MAP sensor. I charted vacuum vs. voltage output with 5V supplied to the sensor. And yes, you could make it ignore that input by tying that input to ground. That would make the circuit behave like there is max vacuum at all times. Then the circuit would only look at BRAKE, SPEED and 4th gear switch.

Keep the comments coming! I have a completed schematic that I have simulated parts of in LTSpice. I ordered all the parts and they should be here by Thursday. I'll breadboard it up after that and start testing on the bench with simulated inputs.
No speed input, but it has to be in 4th gear. It just uses engine vacuum. I didn't like it at first and was going to remove it and just put in a manual switch. The biggest problem was not engagement, but it disengaged as soon as the vacuum dropped. It would disengage and reengage constantly as vacuum went up and down. It made it undriveable. It felt worse than the tcc in the 80's GM diesel cars and trucks. By using the check valve and vacuum reservoir, it doesn't disengage until you're down to 25-30 MPH unless you hit the brakes.
 
This one will mimic the original, but be totally adjustable for speed and vacuum levels at which it locks/unlocks. And the time delay for re-locking will also be adjustable. It will go from a fraction a second up to 4-5 seconds. There will be no lock/unlock/lock/unlock etc. If the conditions for lock are met, the timer starts. If the conditions for lock go away, it stays unlocked until the conditions are met for lock and the timer starts over until it times out and the lock is made. I think it will work great and again, will be adjustable.

We'll see when I get the parts in and get the circuit working with simulated inputs. I will use a function generator for the speed input, a voltage for the MAP input and then switches for the brake and 4th gear switch. That way, I can test it on the bench and work out all the bugs.
 

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