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Feltman

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Joined
Jul 18, 2003
Messages
97
Location
Indianapolis
Corvette
1981 Dark Blue Coup
ok folks..I have been a member fo this forum for a few years. I have asked many questions and received some great help....I have done about as much as you can without taking the body off.....just finished the rear gear swap out this weekend. Still waiting for the motor. Have a 700R4 in the crate (thanks to FourthGear) and hopefully based on the feedback I got, should be able to plug in the TCC harness and have lockup in 4th gear (still not sure about this), but will find out soon enough.....PS...if you don't have to change the heater core...don't do it :)

Does anyone have a wiring diagram of the 81 TCC harness/ECM
 
Joined
Aug 30, 2002
Messages
1,533
Location
Colorado Springs, CO USA
Corvette
84 Z51 auto R.I.P. 89 black roadster SOLD
OHHH how I can relate to the "labor of love" thing!

That looks really nice!

So you'll have some external electronic controller for the TCC?

Bill
 

Peer81

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Joined
May 21, 2003
Messages
2,497
Location
Netherlands
Corvette
'81 Black
Hello Feltman,

Great looking pictures, amazing to see what you have done without taking the body off! Would love to hear the improvements with the rack and pinion steering setup.

Somewhere in the shopmanuals around there I have the original TH350 internal wiring diagram and if I remember correctly I also have the wiring diagram on a 700R4. When I have the time to find them I'll post them here.
If you look in this topic at the first picture.
http://www.corvetteactioncenter.com/forums/showthread.php?t=95638
I'll see at connector N (ecm terminal id) That the 81 ecm terminal is not used but the 82 and later ecm's it is used of the 4th gear lockup. Hope it helps.

Groeten Peter
 

Feltman

Well-known member
Joined
Jul 18, 2003
Messages
97
Location
Indianapolis
Corvette
1981 Dark Blue Coup
Question

I know this sounds to simple, but will a 82 ECM with an 82 TCC harness work on an 81 with a 700R4
 

Peer81

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Joined
May 21, 2003
Messages
2,497
Location
Netherlands
Corvette
'81 Black
I know this sounds to simple, but will a 82 ECM with an 82 TCC harness work on an 81 with a 700R4

Sorry but it wouldn't be possible. An 82 has crossfire injection and the 81 still the cc carb. Easiest thing to do is buy a trans wiring harness from 700R4.com. Then you'll have lockup in 4th but (as far as I remember) not in 2nd and 3rd. But when I find the schematics for the different TCC's I'll post them here. I think it shouldn't be to hard to make the trans lockup in 2,3 and 4th.

Groeten Peter
 
Joined
Aug 30, 2002
Messages
1,533
Location
Colorado Springs, CO USA
Corvette
84 Z51 auto R.I.P. 89 black roadster SOLD
The 700R4 can be set up to engage the TCC in 4th gear via the hydraulic system...no electronics necessary. I'm surprised the trans builder didn't do this?

Otherwise...all that's required is to provide the 12V source to the TCC solenoid, and to connect the other side of the solenoid to ground (that's all the ECM does).

Bill
 

Feltman

Well-known member
Joined
Jul 18, 2003
Messages
97
Location
Indianapolis
Corvette
1981 Dark Blue Coup
The 700R4 can be set up to engage the TCC in 4th gear via the hydraulic system...no electronics necessary. I'm surprised the trans builder didn't do this?

Otherwise...all that's required is to provide the 12V source to the TCC solenoid, and to connect the other side of the solenoid to ground (that's all the ECM does).

Bill

Update: ....my builder has wired the 700R4 for the harness....as long as I have power on the A pin (of the TCC Harness), I will be good to go...cannot check for power until I complete the engine and transmission installation.......
 

Peer81

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Joined
May 21, 2003
Messages
2,497
Location
Netherlands
Corvette
'81 Black
Update: ....my builder has wired the 700R4 for the harness....as long as I have power on the A pin (of the TCC Harness), I will be good to go...cannot check for power until I complete the engine and transmission installation.......

Good to hear Feltman! The A wire always has 12v power except when you push the brake. So you should be all set to go :)

What is going to engage the TCC? Toggle switch?
Some or a pressure switch inside the trans will close when the TCC should lock. This way the 12v from pin A will pass though the switch and will activate the solenoid and ground somewhere in the trans.
In the normal situation the ground wire will go out of the trans and go to the ECM. When the ECM thinks everything is oke it will ground the groundwire so the TCC will lock. Not that difficult if you know where to look ;)

Groeten Peter
 
Joined
Aug 30, 2002
Messages
1,533
Location
Colorado Springs, CO USA
Corvette
84 Z51 auto R.I.P. 89 black roadster SOLD
Good to hear Feltman! The A wire always has 12v power except when you push the brake. So you should be all set to go :)


Some or a pressure switch inside the trans will close when the TCC should lock. This way the 12v from pin A will pass though the switch and will activate the solenoid and ground somewhere in the trans.
In the normal situation the ground wire will go out of the trans and go to the ECM. When the ECM thinks everything is oke it will ground the groundwire so the TCC will lock. Not that difficult if you know where to look ;)

Groeten Peter

Ok that first sentence makes NO sense whatsoever. :confused

I know how a TCC solenoid works...my question was to Feltman and how he is implementing the TCC circuit in HIS case.
 

Feltman

Well-known member
Joined
Jul 18, 2003
Messages
97
Location
Indianapolis
Corvette
1981 Dark Blue Coup
Not sure..but Don from fouthgear assures me that it will work...will let evryone know soon....Tonight, I am the proud owner of freshly rebuilt 350 (my orginal motor), punched out 30 over, some head work, headers...I am on top of the world....hehe!! Not really
 
Joined
Aug 30, 2002
Messages
1,533
Location
Colorado Springs, CO USA
Corvette
84 Z51 auto R.I.P. 89 black roadster SOLD
It sounds like he just routed the neg side of the TCC solenoid to the 4th gear switch...and yeah that should work just fine. It'll just engage the TCC as soon as it goes into 4th gear.

Bill
 

SIXFOOTER

Well-known member
Joined
Jul 15, 2007
Messages
117
Location
Boca Raton Fl
Corvette
1981 L81 Tan Coupe
The harness should work fine, it gets 12v from the brake pedal switch on pin A and a ground on D from the ECM
 

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