just to confirm.
i have the wireing and everything up to under the hood, but have some things cut out when i switched to carb and i think i cut out the VSS wireing. what color wires were they? Purple and Yellow? or black and yellow? (the ones that connect directly to the sensor on the transmission)
secondly, is it in the driver side wireing harness?

 

On my 87 GTA - purple and yellow. Also, it did go through the driverside (C100?) connector.

 

i beleive on my car they were green and yellow.

Will the speedo work without the computer?

 

http://www.austinthirdgen.org/index.php?pid=19

Scroll down to body wiring. No info on 87's but it should get you started

 

there's a yellow and purple wire going into that yellow box under the dash.
from there, where do they go? i can't find any yellow and purple wires under the hood other then a yellow going to the windsheild wipers and a big purple going to the starter. do they change when they go through the firewall?
and that schematics did help, but then not really.
what happened is that three years ago, i put in the 400, everything ran good except the speedo didn't work and the oil pressure gauge didn't work (had an aftermarket anyways). i took out the passanger side wireing harness since nothing connected to anything anymore. i still have everything (harness, computers, tpi, etc).
i looked through that passanger wiering harness and couldn't find any yellow wires.
somebody said green and yellow
i do have a green wire not doing anything out of the driver side harness,
//a pink/black stripe and black in a connector, //and a offwhite and a black in another connector. those are the only wires off the driver side that arn't being used.

could the pink/black-stripe with a black wire in a connector be the one? i don't want to start plugging stuff and fry my vss.

 

No, sounds more like the evap connector, but without a pic we cant tell

The yellow box is your buffer box



According to this, if you have power, ground and the VSS input (Yel/Purple) Pin C should output speed signal to the cluster

Cruise and ECM are irrelevant

You've got VSS input, Id check the power/grounds

 

that wiring diagram is very helpfull, that's the one i was looking for
now, being a novice, i'm trying to associate it with my car.
my goal is to find the correct purple and yellow wire in my car.
is C100 the plug in on the firewall on the driver side?
i have a purple and yellow wire comming out of there, but they go to my windsheild wiper motor.
would an '87 be the same as the '92 diagram?

 

Not in either C100 or C207. Might be in one of the connectors near the ECM (pass side)

Yes C100 is near the booster

 

it's a pink/black stripe with a nother black wire comming from the driver side harness that goes to the VSS on the transmission

in case anybody looks this up.

 

It cant be, there isnt a slot (let alone two) on the C100 for VSS. The only other connector that goes thru the firewall in the vicinity is the cruise harness and GM wouldnt run VSS wiring thru an optional harness.

Plus, they are the wrong colors. Yel/Purple are generic VSS wires for nearly all GM electronic speed sensors no matter the model

http://www.eficonnection.com/eficonn..._pigtails.aspx

Refer to this for what the connector should look like. Green seal is early style -89, red is later 90+

 

hrm..
so you guys gave me answers and there is no yellow wire under the hood that goes anywhere other then one to the windsheild wipers. i looked in both harneses, right at the base.
so i figured that the yellow/purple wire under the dash has to go somewhere. so i took an ohm meter, stuck one end on the yellow wire tip, then had my dad under the hood checking connections that arn't connected to anything with the other end. the pink one with the black stripe, on a connector that looks exactly like the one for the pre 89 vss connector (green) light up the meter. so there was connectivity there. same with the purple and the other wire on the same connector as the pink/black stripe..

1987 firebird formula, 305 TPI, 700r4.

 

Sounds like an emissions connector

Remove the C100 and find what pin its on then use the chart to determine what it does