speedo reads on and off

[90_f20b_cb7]

ok so my speedo wil work some time but not all ways. is the sensor on the 5speed a two wire(yellow and green) on the top of the tranny. its a 19mm to remove it.

cuz it had some frays in the wiring so i rewired it with the same color wire and i still have the in/out prob. so was that the right sensor?

[Jccck]

I've had this problem on both my CB7's

I've gone through 4 speed sensors.. At 0-70 it's spot on
At 80 it reads 75
At 90 it reads 80
At 100 it reads 90
At 120 it reads 105
At 140 it reads 140
At 200 it reads 215

Makes no sense to me
Note, those speeds are in KM/H lol

[90_f20b_cb7]

so any one know what the cause is here? do i need to replace the sensor? will it help keep it from doing it for a bit?

[olock13bt]

Lots of things cause the speedo to be off, tires, wheels, broken parts, loose connections. If you have aftermarket wheels and aren't using the factory size wheels then chances are that your speedo is off. I have seen websites where they can calculate how much your speedo will be off by different tire sizes. Lots of cars have the exact same problem as you are both describing.

The speedo is on the back part of the transmission and you use a 10mm socket to get it off. The 19mm and two wires you are describing is your reverse sensor.

[Jccck]

Sensor won't fix it
And my tyres aren't oversize
If they were, why would it read positive then negative errors anyway?

I think the problem is in the cluster.. But i can't work out what

[Losiracer2]

I had this happen to me just this past week when i swapped transmissions, using the SAME sensor!

But I have a solution. Go to Autozone or whatever auto parts store and buy a little packet of dielectric grease. Slather that stuff inside the connector for the VSS and then connect them together. Should work like normal. Mine worked perfectly after not even working at all on the way to Autozone.

It took me literally less than 2 minutes to put that grease on there. I did it on my break from work lol. Costs like $1.25 with tax.

oh and btw, your speed sensor is on the back of the transmission, facing vertical. The sensor you're talking about w/ the yellow & green wires is the back up sensor.