Do I have a Speedometer problem? - I may have solved it

[Blitzboy54]

I have the FFR Autometer gauges. I have tested all my senders and gauges and they all work normally. All except my speedo. I understand it has to be calibrated and it will be a while before I can take it on the required 2 miles to do it. However, tonight I was dialing in my clutch and whenever I put the car in reverse the speedo jumps and pins itself to 160mph. Then it starts counting miles off. I now have 78 miles on the odometer and I haven't taken it out of the garage yet.

Is this normal non calibrated behavior or should I be reaching out to Autometer? I have unplugged the harness from the transmission

Appreciate any incite you guys can provide


Thank you

Jesse

[Blitzboy54]

OK so this might just be me not paying attention. I for what must have seen like a good reason at the time connected the grey EFI Speedometer return to the "out" on the speedometer. You only need the green wire. After looking at the Autometer instructions there is no scenario where any wire is connected to that lug. If I turn the key in acc then put it in rev with that cable attached it happens. If I unplug it it does not.

The good news is I probably solved it. The bad news is my car now has 87 miles on it.