700R4 TCC Wiring

[pjmoreland]

My buddy printed the box for me last night. Hopefully i will get the PCB by next week

[pjmoreland]

The PCB arrived today. I don't know when I'll be able to test it out because I sent my torque converter back to TCI

[Rich72C10]

well, it looks pretty in that box!

[pjmoreland]

Thanks! Hopefully it works well too. Time will tell

[pjmoreland]

I bench-tested my Arduino controller board today, and everything checked out except for the vacuum sensor which output different results depending on whether I was powering the Arduino from the USB programming cable or a 12V external source. I realized I forgot to connect the AREF (analog reference) pin of the Arduino to the output of the voltage regulator. I had to solder a wire to the back of the PCB to fix this issue. Now the vacuum sensor signal is consistent.

[Rich72C10]

Bug Fix, Version 1.1 ;-)

[pjmoreland]

Originally Posted by Rich72C10

Bug Fix, Version 1.1 ;-)

Exactly :-)

[HO455]

Impressive!

[pjmoreland]

I called TCI yesterday about my returned torque converter. They said the TCC showed normal wear. They are going to replace it anyway. That leaves me wondering why it was slipping. I am going to go ahead and replace the TCC apply valve with one made by Sonnax that has a Teflon seal added to it. I already replaced the TCC solenoid. I am anxious to get back to testing the Arduino controller.

[pjmoreland]

I got my torque converter back from TCI. They said the clutch had normal wear, but they went ahead and replaced the clutch anyway. I've got the torque converter and transmission back up in place, and I replaced the TCC apply valve with a Sonnax 77805-K that has a Teflon seal added to it. I need to go buy a filter tomorrow. I'm anxious to get back to working on the TCC controller! I really miss driving my truck, too.

[Rich72C10]

I'm eager to hear how your new module is working! How did you end up being held back on a filter!?!

[pjmoreland]

Originally Posted by Rich72C10

I'm eager to hear how your new module is working! How did you end up being held back on a filter!?!

That was poor planning on my part. We were out of town for the last several days, and I didn't want stuff arriving while we were gone, so I ordered fluid and a filter late last week. The fluid arrived yesterday, but the filter hasn't even been shipped yet. I'm going to see if the local Chevy dealership has one today.

[Rich72C10]

classic dollar waiting on a dime! LOL

[LT7A]

This is very interesting. Thanks for detailing your process. I'm impressed with how all the components and the box fit together.

[pjmoreland]

My truck is back up and running now, but unfortunately the TCC slippage issue is not completely resolved. It is significantly better, but it starts to slip at about half-throttle in 4th gear. It's at least working well enough to allow me to continue working on the Arduino controller. I'm thinking I'll tune the vacuum sensor trip point to unlock the TCC before it starts slipping. It's not a long-term solution, but I've got other things I need to spend money on right now.

[pjmoreland]

Originally Posted by LT7A

This is very interesting. Thanks for detailing your process. I'm impressed with how all the components and the box fit together.

Thanks! It has been a fun project so far (mostly).

[pjmoreland]

I hooked the box up to my truck for the first time this evening, and it worked. I realized there's a minor issue with the way I'm controlling the LED on the toggle switch. My intention is to turn the LED on when the TCC is locked. The problem is that the power for the TCC is passed through the second set of contacts on the brake switch, so the Arduino has no way to sense when the brake is pressed. One way around this issue is that the vacuum sensor will go to zero when the throttle is closed since it is connected to a timed vacuum port on the carb. The LED will likely already be off before the brake is pressed. The one exception would be if I were to have my feet on the gas and brake simultaneously above 50mph. That's an unlikely scenario. I may add a connection from the brake switch signal to a digital input on the Arduino on my next revision of the PCB.

Next I need to write the code that monitors the vacuum sensor and unlocks the TCC during acceleration.

[pjmoreland]

I added the vacuum sensor logic to the code this evening and went for a test drive. I made a couple of tweaks to the trip points and settled on 12 inHg for the lock level and 6 inHg for the unlock level. I have to say this controller is working quite well.

1) The TCC locks at 50mph and then unlocks at 45 mph. This means the engine never gets lugged by the TCC when coasting down to low speeds when driving around town. This was the main problem with my earlier dual vacuum switch setup.

2) At speeds over 50mph, the TCC unlocks if I press down on the gas pedal enough to drop the vacuum level below 6 inHg. This feels like a natural level to unlock at since the gas pedal is pressed fairly far down either to pass someone or to go up a steep hill.

3) Also at speeds over 50mph, the TCC will lock only if the vacuum is above 12 inHg, which is fairly light on the gas. This allows acceleration onto the freeway without locking the TCC until after you're done accelerating and backing off the gas.

4) I have the vacuum sensor hooked to timed vacuum, so it drops to 0 inHg when coasting. This causes the TCC to unlock when coasting. it then locks back up immediately after reapplying the gas.

I'm planning on adding a feature that allows the TCC to stay locked longer if the gas pedal is pressed down very slowly which would happen frequently when trying to maintain speed on a hill. The code will calculate how much the vacuum level changed from one reading to the next and use this as an indicator of how quickly the gas pedal is being pressed down.

This controller is to the point where it deserves to be mounted permanently in my truck.

[Rich72C10]

great updated, nice work!

[pjmoreland]

I've started the permanent installation of the Arduino controller. The three wires from the transmission TCC will be routed through the firewall bulkhead connector. I removed the engine harness and added these three wires to it along with some new wiring for an electric fuel pump (oil pressure switch, override from starter, fused power from alternator). I wrapped the starter and temp sender wires with temperature resistant Tesa cloth tape.

The next step is to add the three corresponding wires to the other side of the bulkhead connector inside the cab.

[HO455]

I am in awe of your skills and progress.
It may be too late and or not applicable but, I found that I have had to electrically shield the wires from the speed sender on my Gearvendor set up. They were picking up stray voltage from the ignition and causing the controller to freak out.

[pjmoreland]

Originally Posted by HO455

I am in awe of your skills and progress.
It may be too late and or not applicable but, I found that I have had to electrically shield the wires from the speed sender on my Gearvendor set up. They were picking up stray voltage from the ignition and causing the controller to freak out.

Thank you for the heads up on that. My plan at this point is to zip tie the sensor cable to the mechanical speedometer cable. Hopefully that will keep it far enough away from everything else to keep noise issues to a minimum. The three wires I have bundled inside the engine harness are the TCC solenoid wires and the 4th gear switch signal.

[pjmoreland]

My Arduino TCC controller is installed in my truck now with permanent wiring. I'm waiting on a small vacuum hose adapter to replace the gigantic cobbled together adapter I have on there now. It's a little cramped between the parking brake lever and the controller, so I'm going to look into redesigning it to be thinner.

[pjmoreland]

Over the last two evenings I made some changes to the controller PCB and box design to reduce the size. The thickness has been reduced by 0.4", and the length by 3/8". This was done by going to a smaller fuse, by removing the Arduino headers, and by changing out the switch for one that is sideways. I will be ordering new parts shortly. I also made some changes to the box that should make it easier to 3D print based on feedback from my buddy who printed the first one for me.

[Accelo]

You have one of the cleanest under-dash wiring I have seen!
Microprocessors make a lot of things possible for those that know how to harness them.
Great job on the controller. You have put an extortionary amount of effort into the project.
!!