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This is not necesarrily Corvette related but I figured if anyone could help it'd be some of you. I'm puting an Auotmeter electric speedo in my 94 GMC. The VSS has two wires from it to the buffer behind the dash. The buffer has two wires that go to the PCM and one that goes to the speedo. Auotmeter instructions say the "signal" connector should be connected to the VSS and the "out" connector "can" be connected to where the VSS output was originally wired, which would be the buffer. I called Autometer and the rep said just splice into one of the VSS wires and forget about the "out" connector. That dosen't sound right.
I'm thinking the wire exiting the buffer to the dash is the signal from the VSS and that is the wire I need to connect to the "signal" connector. Can anyone help me out or at least give me your thoughts? Thanks :confused:
I would think the Autometer guy would know, but I disagree with him. You have 2 wires from the VSS. The VSS is basically an alternator, it creates a wave form signal. The buffer takes this signal and creates a pusle signal. LT1,TBI, and speed-density TPI is 4000 pulses per mile. Mass-air-flow TPI is 2000 pulses per mile. I think all you need is the 4k pulse signal that originally went to the speedo (brown or tan wire I think) to the input on the new speedo.
markdtn, thanks for your input. I think I'll connect the original speedo wire to the signal connector on the Autometer. If that doesn't work I'll go to another plan. If it provided the signal for the original speedo I hope it'll do the same for the Autometer.