So after a recent motor swap, my speedo started acting finicky. It was fine for the first hundred miles, then it began to skip around, until it finally stopped working completely. The symptoms are exactly that of a bad electrical connection. It randomly comes back to life, and has worked about 50% of the time up until this weekend when it has stopped for good.

I pulled the VSS out yesterday to check its physical condition. I popped the top off of it to check the wiring. The grease inside surrounding the 'wheel' at the top of the shaft where the electric sensor picks up seemed dried up and 'cakey', so I scooped it out and cleaned everything up. Upon reassembly, I repacked that area with the dielectric grease I had used on the connector.

Now that everything is back together and installed with the corrosion cleaned up, the speedo is still dead as a doornail. I'm getting continuitiy to ground from the black wire, battery voltage from the black/yellow wire, and a steady 4.62v from the blue/white signal wire whether driving or sitting still. The service manual calls for 5v or more from the signal wire. I'm not sure how significant that is, but the point is it's not working. Now I'm wondering if that dielectric grease might be preventing the inductive capacity between the sensor pick-up and the wheel. So... bad sensor, or stupid move??

EDIT: VSS is from a Prelude Si, M2S4 tranny. Voltage was read from VSS pigtail while plugged up to the engine harness.

 

I just had a VSS that was bad on my racecar, tryed cleaning the plug but it came down to having to remove the pins from the connector and putting in new ones. You couldnt really see the crud that was inside.

 

the connector on my 95 integra vss went bad. once you pulled out the white plastic pin guide from the connector you can see the original terminals were burnt/corroded.

i had to cut a vss connector off another harness and solder it onto my harness. works perfectly ever since.

 

It still could be a bad VSS sensor but I have heard (read about) more issues with just the connections.

 

Sounds like I could recheck my connectors to be safe. I'm still curious whether the dielectric grease could be a problem...

 

I think it was a smart move.. just bad timing.