Bouncing speedo, fuse 15 good

[SW20FL]

I have a 1997 Civic DX 5 speed. My speedometer just started bouncing around out of nowhere today. It still works, but it reads inaccurate. It doesn't read until I'm moving ~15-20 mph and then quickly catches up. IT is accurate at around 25-35 mph, then at 40-50+ mph it reads 10mph higher than I'm going. At even higher speeds, it reads 20-25 mph faster than I'm going. It was at 85-90 when I was going 65mph. Then the needle starts to bounce around just a little bit while I'm at a constant speed.

I searched the forums, and saw many people mentioning to check fuse 15 under the dash. I checked fuse 15 7.5A. That fuse is good. I removed the VSS, and I don't see how I can clean this thing. It's just a gear connected to the sensor. The gear isn't stuck or anything either. I didn't get a CEL, but I have to assume I have to drive a while before it finally decides to throw a CEL.

This just started this afternoon. I've put 31,000 miles on the car, and it's been trouble free. 0 modifications besides an aftermarket head unit and a small 150 watt amp with an 8 inch sub. It's just a regular commuter car.

Any ideas?

 

[SW20FL]

Update:

I cleaned the VSS. Took the gear/shaft out of the sensor part, and cleaned it up. Has some corrosion, but nothing bad. Put it back together. The speedometer worked perfectly for about a half a mile, then started to act up again. Haven't found the fix.

 

[mahalo]

my speedo bounces too and i cnt figure it out either.my CEL is on but its throwing an o2 sensor wich i dont see how the 2 would be related. try checking yourfuse with a tester light just in case. pm me if youfigure it out htough

 

[RonJ]

Update:

I cleaned the VSS. Took the gear/shaft out of the sensor part, and cleaned it up. Has some corrosion, but nothing bad. Put it back together. The speedometer worked perfectly for about a half a mile, then started to act up again. Haven't found the fix.

A very common problem is the VSS plug. Check for any corrosion or damage. Clean or replace the plug as necessary. People who need to replace it usually get one at a junk yard.

If the plug is fine, then the speedo itself may be bad, but before replacing, carefully inspect the cluster plug terminals.

 

[RonJ]

my speedo bounces too and i cnt figure it out either.my CEL is on but its throwing an o2 sensor wich i dont see how the 2 would be related. try checking yourfuse with a tester light just in case. pm me if youfigure it out htough

I know that you have looked, but you surely have a short in the wires near connector C115, as described in the fuse 15 TSB. Those shorted wires are not always easy to locate, but it is there if you take the time to patiently search for it.

 

[SW20FL]

A very common problem is the VSS plug. Check for any corrosion or damage. Clean or replace the plug as necessary. People who need to replace it usually get one at a junk yard.

If the plug is fine, then the speedo itself may be bad, but before replacing, carefully inspect the cluster plug terminals.

Checked the VSS plug at the sensor on the tranny. Unplugged it. Didn't see much corrosion, but cleaned it anyways with a Q tip. Removed the cluster and cleaned the connections. Removed the cluster, then removed the speedometer from the cluster, and blew off any dust on it. I didn't see anything out of the ordinary. Put it all back together.

Took the car out. It behaved for a lot longer perfectly. Then started to bounce around just a little bit....just a little bit. The speed is accurate. I think it may be a bad speedometer gauge assembly.

Is it possible to adjust the mileage on the cluster by turning it by hand? When I buy a new speedometer, I want to set the mileage to exactly what mine is at.