andyww

Looking for a good starting point. My speedometer recently started acting up. After the car sits for a while the speedometer does not register until you get up to about 30mph. Even then it "responds" slowly. Seems like the longer it is driven the better it gets. Any ideas?

My car is a 86.5 with a 5 speed.

Thanks in advance for any help

Ducman82

hows the sensor on the diff cover? wiring ok?

MainePorsche

I'm not sure about the 86.5 but I think the wiring is the same as my S4. Start by checking the wiring and the spare tire area. On the fore wall there are two white harness connections. Clean them up. Do this before proceeding to a pod/cluster pull. As mentioned check condition of the wires at the sensor on the back of the differential.

OTR18WHEELER

From what I know, long story short, ....
Pick ups and sensor are at the diff, connector is fore and above the battery box, resistor behind speedometer is another fail point.
A failing ODO gear will put strain on the worm gear drive motor, frying the circuits behind the speedometer unit.