Armstrong

Am I right in assuming that the computer on a 81 controls only the carb and the the transmission. I was wanting to remove the computer and replace my intake and carb with a noncomputerized one. What would I need to get to make the transmission still operate normally. Also when I get a new intake do I need one with the egr hookup or not. Was looking at the performer.And yea I know I might as well do a cam swap.

Dalannex

Your computer controls the carb, torque converter lockup, and timing advance. To do away with the carb, you will need a different carb, and a distributor at least. The transmission will still operate, only you won't have any lockup. (If I'm wrong about this, somebody let me know) You can get a vacuum switch to make the lockup work properly without the computer. I don't remember who it was that has that setup, seems like it's Gator81, but I'm not sure. I'm sure they'll post what car they got that vacuum switch for the lockup off of. I don't know for sure if you want to go with EGR or not. Either way, the computer isn't needed for EGR.

John's 81' mouse, UKPaul, and Gator81 would all be good ones to take advice from on this topic. Come on guys, where are you? :D

corvettemaster

I am planning on taking all that computer and alarm wiring out of my 81 after it warms up. Probably this spring/summer. Dalannex is right about what the computer controls. As for allowing the lock-up torque convertor to still work without the computer, just use a switch. I bypassed the computer and hooked mine up to a switch. Mine was just a regular switch, not a vacuum one. But I probably wired mine up different. :confused:

Dalannex

That's correct. They can be wired onto a switch. I think that's how most people do it, but with the vacuum switch method, you get a vacuum switch off of some car or another at the old salvage yard, hook your tranny wires up to it, then hook it up to manifold vacuum and it locks and unlocks the converter for you. Just like factory, only without the computer.

Justin

VegasJen

what is wrong with the computer in your '81? i can't think of anything that would make me want to get rid of mine. burns clean and gets over twenty miles to the gallon on flat ground. what is your car doing that you want to get out of the computer controls? and if you really want to, i'd be interested in the computer, distributor and carb.

john's '81 mouse

If you don't want / need the EGR, you can go with Edelbrock Peformer 2101, that's what I have. Must install different HEI distributor, one that has vacuum advance, and then wire switch or use vacuum controled switch, like Justin said, if you want lock up torque convertor, which is advisable, if you do highway driving and mpg, is important to you.

Don't go too wild on cam swap, if you still have original rear gears. Too much duration will destroy your low end torque on this L81, low compression engine.

Suggest you consider replacement or elimination of Cat Convertor, and going to dual exhaust as well.

UKPaul

Ditto the above question but if you do want to remove the computer then a new carb & dist. will be needed. Also some sort of switch to allow converter lockup. To remove the computer just unplug it! If you want to remove all associated wiring then do it one piece at a time - don't just cut it all out in one go. Some connectors have 2 wires on one terminal & cutting them off might prevent power getting somewhere that needs it :( Also take out the Check Engine light bulb (or cover it up).
The EGR & AIR system has been removed from mine with no bad effects.
Good luck
Paul
p.s. your computer (if you junk it) wouldn't have a performance chip in it would it? ;)

Armstrong

Thanx to all replies. At the present time I am just considering this. Your response's help me decide. Just bought this Beauty and it needs alot of work. Right now the engine runs GREAT! All smog junk has been removed and I have loose wires running all over the place. My exhaust has the tubes sticking out the top of the tube manifolds. It does have true duals and the cat system has been removed. Just trying to figure out where to go from here for now. John's 81 Mouse sounds about what I want.

8T1-7T9 BIONIC VETTE

I have the computer out of my 1981.......you want it.....you pay cost of shipment.....it's yours....Cappy :seeya

UKPaul

Well.... if nobody else grabs it, would you be up for sending it to the UK? Is it for a TH350 'box?
:cheers:
Paul

VegasJen

o.k. paul, if cappy's computer is for a stick, it's mine--if it's for an auto, it's yours. sound fair? cappy, you out there?

UKPaul

Sounds good to me. Hope he can send some of the lovely Honolulu weather with it :)

81ZZ4

Just unplug the computer.....no need to take it out. It's in the battery compartment anyway.
Put in a GM HEI distributor and get a B&M lock up switch.

It plugs in to the trans and the speedo cable. Lock it up or leave it unlocked at whatever speed you desire. It works very nice. A small green led shows locked and red is unlocked. Adjusts on the fly.


[Modified by 81ZZ4, 9:59 AM 2/4/2002]

vert2go89

I have an 81 also and my cmputer is not connected and my lock up is not working.Is there a wire coming out of trans case for lock up and if so where might it be?I only get around 15 mpg and would like to see 20mpg.All my smog parts removed and hei dist with quadrajet carb.
Thanks for the help. Wave on ! \ ////

UKPaul

Hi smiles!
There is a connector (assuming you've got a TH350) on the side at the left of the g/box. There are 4 contacts in the connector, only 3 of which are used. The wires that attach to the connector run up the side of the engine to a harness connector somewhere around the rear of the drivers side valve cover.
You need to connect a 12V supply to the A terminal (an ideal supply would be the one from the TCC brake switch - then your converter would unlock when you hit the brakes) & run the D terminal to a switch somewhere inside which you'd use to lock/unlock the converter. The C terminal is some sort of gear indication to the ECU & the B terminal is unused. All that happens with the computer is that it earths the D terminal when it wants to lock the converter, so you'd just be replacing an expensive computer with a cheap switch :)
The 12V supply from the TCC brake switch is a purple wire? (this is from memory :( so could be wrong!) that connects to the TCC/EGR bleed relay.
:cheers:

vert2go89

Thanks for the info and I will check it out when I find a round to it.
wave on! \ ////

Golden80

Also be careful as a lot of emissions testers will look for the Check Engine light to come on for a few seconds when they start the car. Best solution to this is to wire it up to the choke light.

I'm planning on keeping mine until I do my ZZ4 swap in 5 years when I graduate. By then I won't have to E-test it. I'll be safe though and get a chip for the ZZ4 for the computer so that if I sell it I can hook up the comp and everything (carb, dist, tranny) so that it'll pass an E-test. I don't have any plans of selling it though but it'd be safe to keep just in case!

Matt