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It won't confuse the ECM. There are no DTCs associated with lock-up in 1987.
At the ALDL connector there is a tan/blk wire in cavity F. this is TCC. Short this wire to ground and TCC is applied if the transmission is in 2nd gear or higher. There is no TCC possible in 1st gear, as there is no TCC signal oil present at the solenoid until the trans shifts into 2nd.
Really? So there's no strategy change when there's lock up? Not to mention the lube circuit in the tranny that's necessary.
Last edited by Mrvettenick; Aug 8, 2020 at 11:53 AM.
I gave the guy what he asked for. How to manually override or manually defeat TCC apply.
I'm not going to argue about a system I know pretty well, and have been working with for over 40 years.
The ECM won't know or care if the tan/blk wire is grounded externally. There are no DTCs for TCC in a 1987.
I did mention the "lube circuit" which is not "lube" at all, but Converter Clutch Signal Oil. This oil is not present until 2nd gear.
When I mentioned lube circuit, I wasn't speaking about TCC apply pressure. Apparently, you know better/. So, I'll end it here.
When I mentioned lube circuit, I wasn't speaking about TCC apply pressure. Apparently, you know better/. So, I'll end it here.
IHBD is correct. TCC clutch solenoid does not care what is grounding it. A manual switch can be hooked up in parallel with the ECM and it will operate just fine. An 87 does not have a strategy, it is on or off. Lube circuit has nothing to do with the TCC.
You're missing my point. I'm speaking of fuel and spark timing strategy. The lube circuit is activated through the lock up hydraulic circuit. If you change TCC engagement, or eliminate it for long periods, the components fed by that circuit will eventually fail. It makes no difference to me, but. I wouldn't do it. Unless there's a specific need to do it.
You're missing my point. I'm speaking of fuel and spark timing strategy. The lube circuit is activated through the lock up hydraulic circuit. If you change TCC engagement, or eliminate it for long periods, the components fed by that circuit will eventually fail. It makes no difference to me, but. I wouldn't do it. Unless there's a specific need to do it.
Sorry but you are going to have to explain. Tell us how you think spark and fuel have anything to do with a 700R4 lube system. Describe your idea as to how the hydraulics work.
Mrvette, and barking dogs....man I didn't mean to stir up anything....all I'm wanting to do is install me a switch to manually lock and unlock my torque converter. After it shifts from second into third it just falls on its face unless your in the gas because of the converter unlocking (right?)...and I usually only use OD on the hwy, or flat roads. But I'd prefer if it didn't lock or unlock or whatever it is in third unless I wanted it to, and there's times forth gear with out a lockup would be nice. Owned this Vette for three years mow and haven't gotten to having a shift kit installed yet. I have played with the TB cable to get it to shift a little later/firmer (and yea I know, every little click matters on that cable)....
bit guys, thanks for the input!.. there's a lot that goes on on them transmissions. Thanks for laying alot of it out... I'ma look for that wire at the brake pedal, and install me a cool switch!...
Na,....installing a toggle or push button switch really isn't any grief!...there fairly easy to install...
air and fuel,...we were "getting sideways" down the gravel roads along time before "drifting" ever was thought about!....I can drive, and know all about using a gas pedal!....lmao.....
Tell us how you think spark and fuel have anything to do with a 700R4 lube system.
It's not the lube system, he asked:
Originally Posted by Mrvettenick
You're missing my point. I'm speaking of fuel and spark timing strategy.
Which is a valid question because it does. I can't speak specifically to the 87 as I never had an 87, but I am going to make a safe assumption that it too has the TCC tables in the tune or some version of them. There is a SA retard at TCC lock up table, but it is not a huge retard, just a few degrees. However, there is a set of tables related to TCC lock up for high/low gear for disengagement based off TPS% and a set of scalers that control the TCC function based off speed.
I think the real question is, does the ECM recognize the switch being made or not.
The proper way is to get it tuned to behave the way you want it and let the ECM control it, the shortcut is a switch.
I understand your frustration, I have adjusted some settings in my tune to get rid of that bog feeling when it won't unlock quickly at low 4th gear speeds.
My understanding from the Turbo Buick guys is this actually allows them to run better 1/4 mile times by locking it early. What you are describing is wanting it to come unlocked faster. I think your switch will need to interrupt the ground to keep it from locking.
I have used a console button to manually operate the converter clutch for decades. I just intercepted the tcc wire going to the soleniod in the tranny and fed that to a switch. I also go through a relay so the "od" light on the dash lights up when the switch is activated (my car originally had a 4+3). I lock up the converter after the 2-3 shift at the strip. When the car was on the street, it was like a fifth gear on the freeway.
Which is a valid question because it does. I can't speak specifically to the 87 as I never had an 87, but I am going to make a safe assumption that it too has the TCC tables in the tune or some version of them. There is a SA retard at TCC lock up table, but it is not a huge retard, just a few degrees. However, there is a set of tables related to TCC lock up for high/low gear for disengagement based off TPS% and a set of scalers that control the TCC function based off speed.
I think the real question is, does the ECM recognize the switch being made or not.
The proper way is to get it tuned to behave the way you want it and let the ECM control it, the shortcut is a switch.
I understand your frustration, I have adjusted some settings in my tune to get rid of that bog feeling when it won't unlock quickly at low 4th gear speeds.
My understanding from the Turbo Buick guys is this actually allows them to run better 1/4 mile times by locking it early. What you are describing is wanting it to come unlocked faster. I think your switch will need to interrupt the ground to keep it from locking.
Thanks for speaking your mind. I agree the ECM doesn't know. But when it commands the clutch to engage. it believes it's working, and bases its' strategy off that. Th other issue is the ECM is doing this 100 times s second. a lot faster than a human. The only exception to this id if you convert to a carb that is totally independent. Then...OK, but unless that trans has safeguards for proper lube, I wouldn't do it.If you're happy and comfortable doing it, then by all means. It is your car..
