Okay, I know this has been beaten to death, but I have a speedo question. I am in the process of converting my 91Z TPI to carb. I went through the wiring harness, and was able to disconect the ECM, and the ECM harness. I took the ECM out, and left the harness in tact, but removed it from the car also. There is a conector that is for the VSS(speedo?) that I had to remove b/c it went into the ECM, it is a yellow wire, and a purple wire. I traced it to the ECM, but nothing came out of it. My search results netted 172 matches, which at this time, I don't have time to read all of them. One did mention the yellow box. I don't think I have one of those. All I noticed nect to the ECM was a little black one, but none of the wires I removed went to it. Can anyone please help me with where these should go, or what I can do to keep my speedo.

Thanks,


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Joshua Johnston
1991 Z-28
Flowmaster
K&N
305 / 5spd. (Temporary)
Soon to have:
350, Ported Vortec heads, Edelbrock RPM, Holley 750 D.P., HEI, 11.07:1 CR, Comp Cams Roller-.510"/.520"-282*/288* dur., Shorty Headers, Dual 2.5 Exhaust, T&R Motorsports custom air intake

 

The the yellow box is called the VSS buffer. Your car doen't have one it is in the computer. but all you have to do is get vss buffer from a tbi car. I'am not really sure on the years but I got mine from 90 RS. Then just connect the yellow and purple wires to the input side. there are three wires on the output side two brown, one red. One of the brown wire goes to your speedometer and the other goes to the computer. The red wire is for the cruise control.

 

Tad,
So the brown to the computer, do I just not use that since I took out my ECM?

Thanks for helping,



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Joshua Johnston
1991 Z-28
Flowmaster
K&N
305 / 5spd. (Temporary)
Soon to have:
350, Ported Vortec heads, Edelbrock RPM, Holley 750 D.P., HEI, 11.07:1 CR, Comp Cams Roller-.510"/.520"-282*/288* dur., Shorty Headers, Dual 2.5 Exhaust, T&R Motorsports custom air intake

 

You would only connect what you need. One brown for the speedometer,and the red if you are using criuse control.