Erratic Speedometer

[Unregistered]

Dear fellow E34 fans. Has anyone ever experienced speedometer problems as follows: Once I get up over 50MPH or so, the speedo will intermittently drop down 10 or 20 MPH for a split second. It has done this since I first owned the car, and has gotten progressively worse.

Any insights on how to repair would be appreciated.

Jeff Griffin
ja_griffin2001@yahoo.com

[gale]

If it's the speed sensor (which is located back of the differential cover) it could be as simple as only needing to unplug & clean the connector/socket. Sometimes the sensor will attract and build up ferritic fuzz and cleaning it off might correct it, but it's a total pain in the butt to change the sensor with the diff in the car so if you go to the trouble to remove the sensor, replace it with a new one, about $36 at the dealer. There was a part change for the sensor around 09/91 but they are interchangeable function-wise. The earlier style has about 6" of leads for the connector whereas the newer style has the socket as an integral part of the sensor.

It could also be related to the instrument cluster "Capacitor Fix" but if all the other gauges & trip odo are working fine, then it's more likely the speed sensor.

gale
92 735i 5-spd, 162k