QuickStyle

I bought an autometer speedometer #4488 programmable 3-3/8" everything is hooked up good 12v, ground, signal, lighting, and the calibration is set good. problem im having is anytime below 60 mph it spikes anywhere up to 160 mph, the slower i go the further is spikes.... if im going 1-10 it spikes to 150-160, if im doing 10-20 it spikes to 140-150... etc... etc... when it gets to 50 mph it spikes to 60 at most, but once i hit 60 mph and above it perfect, no more spiking. also the mph reading it accurate except for when it spikes. it only spikes every 3-4 seconds and when it does spike its only for a second or two.

I have contacted autometer and per their tech info they asked me to wire the ground from the gauge to its own ground, no other grounds near it, also to make sure the signal wire is no where near a high amperage circuit. i have did both and still the same results, spiking. i also went ahead and tried adding an additional ground from the vss straight to the chassis, but it didn't help. by the way i hooked it up through the vss not the ecm ouput signal, like autometer recommended. autometer suggested that i send the unit back in to have them repair it, but i would like to first check to make sure everything on the car is in working order before i send it in just to be told it is fine, any suggestions? the vss and the drive and driven gears are brand new also, Is there anyway to test the vss signal?

iceinespana

See the threads for diagnosing speedometer problems. Almost all the info you need to test your circuits are in those threads.John

QuickStyle

I have spent several hours searching for speedometer related thread, some good info out there. I also read the thread you started iceinespana about your speedometer, good info there too. however i took upon myself to measure the AC volts from the VSS on the back of the speedometer, and it is pretty consistent, 0.00 at a dead stop and progressively gets higher with speed, about 2.5 volts per 20mph. so i would think that the vss and the wiring to the speedometer is good. maybe i did get an out of the box bad speedometer unit and i should send it back, any input on this?

heres a video of what its doing while driving
http://www.youtube.com/watch?v=yNdmTFEzKa8

this video is of the car in drive creeping at maybe 3-4 mph
http://www.youtube.com/watch?v=2hUMxXT9Gqs