Electric speedo problems

[B Schein]

I am trying to hook up an Autometer electric speedo. The car has a tune port motor with street and performance harness and computer. There is a green wire that comes out of the harness label VSS 4k pulse. I Got the gages from Covans with the dash insert so everything was pretty much pre wired with an American Autowire harness. On there body side harness there is a yellow and purple wire. The yellow wire is labeled VSS ground and the purple is VSS signal. As far as I can tell you only need to use the Yellow wire if you are using an autometer haul effect VSS sender. The directions form the speedo say it should work with a sin wave single from 500-400,000 pulses per mile the computer should be putting a 4000 pulse sin wave so it should work. I hooked up the green and purple wires followed the calibration directions and the speedo doesn’t read any thing any one have any Ideas.

[73z-6sp]

I think that the green wire may be for the engines' computer use and I am not sure if you need it or not. My RamJet 350 doesnt require a VSS signal. The two wires for the harness that you mention sound like the two you need. Usually the signal wire is the purple wire. On my 700R4, there is two wires that come off the sending unit. One is connected to ground and the other is the signal to the speedo. You need to ground it or it wont have any reference. It could be that the yellow wire runs to a ground somewhere within your harness meaning you dont need to ground one of those sending unit wires near the trans like I did, but check it (the yellow wire) to be sure. Hope this helps.

[AAW]

Brian,
Tune port motor ECU requires 4K pulse. Make sure the VSS you are using is a 4K pulse. That would be stock.

Autometer gauges can handle any pulse generator from 500 to 400K pulses.

Tie the purple wire to the VSS signal lead directly. Do not use the 4K wire from the ECU for the Autometer gauges. This wire is the signal lead to the ECU from the 4K pulse VSS. Ultimately you are creating an inline splice from the VSS signal to the ECU and the Autometer Speedo signal input (Purple wire).

Tie the yellow wire to the VSS ground lead. Ground the yellow wire in the dash. The VSS ground lead can also be grounded at some other point by the transmission.

If you are using an Autometer VSS, this is a 3-wire lead. One ignition, one VSS signal and one ground. This is not a 4K pulse VSS. This is why you must use a stock tune port 4K pulse VSS.

You can also use the ECU speedmeter output lead. Check with Street and Performance as to which wire this is. They may or may not provide it in the harness. If they do, it will be a 2 or 4K output which can be used by the autometer speedo. The 2 or 4K depends on the year of the motor. If they do not provide it, then do as I explained above by the inline splice method.

I hope this helps.
Have a nice day.

[B Schein]

I got everything working today I hooked it up like Teresa suggested with the three-way splice purple to purple and yellow to yellow but it didn’t work. I gave speed and performance a call. It turns out for some reason they decide to wire there harness purple as ground and yellow as signal this is the exact opposite of how the Autometer gage wires so I switched them around and everything works perfect know.