What Are These Connectors
Thread Starter
Pro
Joined: Oct 2000
Posts: 564
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From: Riverview Florida
What Are These Connectors
Inside the battery compartment of my '81 are 2 large electrical connectors on the ends of wire bundles that come from the back of the center armrest area. The connectors are both female and I can't find anything to plug them into. Everything on the car seems to work. What is this mass of wiring for? I have had the car at home for only 2 weeks and am still in the "discovery" phase. 
Safety Car
Joined: Jan 2004
Posts: 4,776
Likes: 142
From: North of Atlanta GA
St. Jude Donor '05
Get the wiring diagram for the '81 (ebay), look over the offerings carefully, they vary in quality and detail, also look for the service manual, all will come in very handy.
Thread Starter
Pro
Joined: Oct 2000
Posts: 564
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From: Riverview Florida
The computer was in the battery compartment? How much of a computer did the '81 have? What did it control? Previous owner installed a crate motor with Edelbrock carb, no smog stuff of any kind, headers, no cat. There also doesn't seem to be any lockup function in the torque convertor.
Melting Slicks
Joined: Jan 2000
Posts: 2,386
Likes: 3
From: far, far away
Our O-T-D friend is right on the money: computer connectors.
The '81 was the last Vette with a carb and the first with an ECM computer. The carb was the E4ME, just one year on the Vette but many years on GM trucks and a few other GM vehicles in the early 1980's. The ECM took input from sensors (exhaust O2, throttle position on the carb, intake manifold temp, intake manifold absolute pressure, maybe a couple of others I can't think of right now) and ran that data across a couple of simple tables stored on a chip to determine and adjust the mixture needles in the carb primaries, and the ignition timing (no vacuum advance). Aftermarket chips are available to make that ignition timing table somewhat more aggressive, for higher compression and higher octane fuel.
There is supposed to be a top-gear lockup on the torque converter, as well, but I don't know much about that... my car's a 4-speed. However, I know a couple of 81'ers who can tell you all about it. Look for postings from UKPaul if you want to ask about it.
Sounds like this is all ancient history for you, tho. Have fun with it!
Edit: a link to my car's info.
http://www.rogerscorvette.com/free/morris.htm
The '81 was the last Vette with a carb and the first with an ECM computer. The carb was the E4ME, just one year on the Vette but many years on GM trucks and a few other GM vehicles in the early 1980's. The ECM took input from sensors (exhaust O2, throttle position on the carb, intake manifold temp, intake manifold absolute pressure, maybe a couple of others I can't think of right now) and ran that data across a couple of simple tables stored on a chip to determine and adjust the mixture needles in the carb primaries, and the ignition timing (no vacuum advance). Aftermarket chips are available to make that ignition timing table somewhat more aggressive, for higher compression and higher octane fuel.
There is supposed to be a top-gear lockup on the torque converter, as well, but I don't know much about that... my car's a 4-speed. However, I know a couple of 81'ers who can tell you all about it. Look for postings from UKPaul if you want to ask about it.
Sounds like this is all ancient history for you, tho. Have fun with it!
Edit: a link to my car's info.
http://www.rogerscorvette.com/free/morris.htm
Last edited by Gator81; Dec 30, 2004 at 10:04 AM.
Thread Starter
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Joined: Oct 2000
Posts: 564
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From: Riverview Florida
Gator81,
Thanks for the great info. With the new motor and trans I guess there's nothing left for a computer to do. The car runs well and so far I haven't found anything that doesn't work so I will keep enjoying it. By the way, did the computer control the electric fan or is that just on a temp sensor somewhere? Mine runs as soon as you turn the key no matter what the engine temp is.
Thanks for the great info. With the new motor and trans I guess there's nothing left for a computer to do. The car runs well and so far I haven't found anything that doesn't work so I will keep enjoying it. By the way, did the computer control the electric fan or is that just on a temp sensor somewhere? Mine runs as soon as you turn the key no matter what the engine temp is.
Melting Slicks
Joined: Jan 2000
Posts: 2,386
Likes: 3
From: far, far away
There's a thermal switch screwed into the passenger-side cylinder head on the stock '81 that controls the auxiliary electric fan. Perhaps the crate motor in your car has heads without that provision. I believe it is a 3/8" NPT threaded hole, about the size of your little finger. Might be 1/4" NPT. I don't recall right now whether the hot wire goes to the switch first and then to the fan to ground, or the other way around. Sounds like yours has been wired to bypass the switch, tho. For a lot of Vettes, that's not a bad idea, especially with a hot aftermarket motor and an auto trans that makes extra heat.
[edit] I forgot to ask: Where's Riverview? I'm a FL native.
[edit] I forgot to ask: Where's Riverview? I'm a FL native.
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