I'm going to wire up an electronic autometer speedometer into my '81 El camino that I used a wrecked '88 GTA as a donor. Should I ground one side of the VSS and run the other side to the input for the Autometer speedometer, and use the "out" from the speedometer directly to the ECM since the speedometer provides a buffered output? I would no longer have a need for the yellow box (VSS Buffer) right? Please help

 

TTT

 

Roc, long time ago....but did you ever get an answer? I'm trying to hook up an autometer speed sensor myself.

 

Nope, never got an answer. I wired one side of the VSS to ground, and the other to the input of the speedometer. Wired the output on the back of the speedometer directly to the ECM. Have not hooked up a scanner to the ALDL to be sure the ecm is seeing the correct speed, but I believe it'll show either 1/2 or double what the speedometer shows. Hasn't been an issue though, TC locks up and the SES light isn't on for a VSS problem.

 

Roc, thanks. I'm using an autometer Hall VSS so I think I'll have to wire the red lead to a 12V source, black to ground and the signal wire to my yellow lead where the original VSS pigtail was. What should I do with the purple wire (original VSS has yellow and purple). the yellow is the VSS high signal and purple is VSS low.

 

Ground the yellow "VSS low" wire to the transmission. The hall-effect VSS is referenced to ground so the ECM's VSS input will also need to be referenced to ground.

Also, FYI, the yellow box behind the cluster will not be needed. It's not so much a buffer box really....more of a signal converter to turn the signal from the optical sensor on the back of the mechanical speedo into something the ECM can use.