Let me give as much information as possibel so as to get a correct responce to this. I have an 87 IROC-Z with manual speedo which I have put a T-56 into. I am wanting to go with an Autometer electric speedometer like some of you have. My question is this. When using the Autometer electric speedo is it possible / necessary to hook up the wiring that was originally on the back of my factory speedo. The wiring I am refering to is the two wire plug in that has the eye on it which reads how fast the original manual speedo is turning. With the speedo disconnected like it is now this causes the SES light to come on because the computer is setting a VSS code.

Is there a way to connect this wiring to the Autometer speedo ?

I have been told that the Autometer speedo has an output wire on it. Can this be used to connect to the computer and correct the problem of the computer not knowing how fast the car is moving ?

ANY help with this would be greatly appreciated.

 

I forgot something in my original post......
FYI: The factory plug in with the eye on it I refered to is hooked to a small yellow box that is attached to the back of the insturment cluster. Don't know if this helps but I thought I would mention it.

 

I have the 3.5: Autometer Electronic speedo and a t56, but my car is an 85 Berlinetta, so I haven't run into the SES light. It's been about 2 years since I put it in, but I don't remember there being an output from the speedo. Things may have changed since then.

That yellow box is the speed buffer, it's basically some circuitry that mulitplies the signal from the eye on the speedo to get a certain pulse per mile for the ECM and cruise control. You would need to run an output from the speedo to the input on the yellow box. The only problem is that the t56 puts out 256000 pulses per mile where the cable is only about 2000 pulses per mile.

Whenever I get the time, Iplan on making a muliplyier circuit so I can hook up the t56 sensor to my yellow buffer box so that I can get my cruise control to work.

good luck
Dave