Hi all, I have searched through the archives and found that usually when the speedo starts acting up it's the sending unit, also reference was made to purchasing a VW unit IIRC. But as my car doesn't seem to fail in the usual ways I am offering my symptoms for your diagnosis: Speedo needle does not rest at 0 mph but at 10 mph Recently speedo will bounce up to max speed then back down, this happens in a fraction of a second, then everything seems to return to normal Today, speedo stopped working for a matter of seconds. NO , I didn't think to check the odometer at the time. What say you all? Thanks, Lester
Search again - it all sounds pretty typical - you're not the first person not to notice the pin preventing the speedo reaching zero either !
Speedo is supposed to rest at 10. If it doesn't, the near invisable needle stop is broken. The car is "moving" ...... even when standing still. Rest I'll leave to the really smart guys.
Sender failing I would say. Check the connections just beside the sender (iits at the front left corner of the gearbox) but what you describe is pretty typical of a failing sender. To change it you will need a long reach (deep) socket (30MM iIIRC but check it) - needs to be long enough to go over the wire tail so that you can get it onto and undo the sender. I found you can't get an open spanner (wrench) onto it. And no, oil doesn't come out when you undo it! (or at least it didn't on my 328).
Ditto the 10mph setting and using a very deep socket to get it out. These are notorious for failing speed sensors. Dave
Mine did this a couple of years ago during a drive. Speedo just went crazy for a few miles and then would be OK for a long period of time. One evening while doing maint, I cleaned and checked the connections in then dash behind the speedo and those at the sender. The area around the sender was pretty dirty from road grime, oil and such so I spent a lot of time in there cleaning the connections really good. I had a can of terminal cleaner to use which worked good. Since doing this the speedo has worked flawlessly and that was a couple of years ago. I didnt find anything in the dash to indicate a problem so Im about 90% sure whatever it was, was at the sender. Having said all of that, I would do a good service job at the sender and see if that cures the problem. If not, most likely need to replace it. Im not sure what (if any) fuse or wire terminal at the fuse (etc etc) is connected to the speedo but with the history of electrical issues in these cars at the fuse block, that would have been my next step. Birdman may have some info about that? Hope this helps.
Despite this very very very common problem, all indicated milages on ALL these cars are ALWAYS 100% correct. No exceptions
Yes mine has the same low mileage it had 5 years ago, despite my driving it a lot!!!! Should have that problem fixed tomorrow though! T. Rutlands sent the wrong speedo sending unit 5 years ago, but Rock's Auto in Toronto sent the correct one this winter, or so it seems! It's in the shop tonight for other "stuff" as well as replacing that sending unit. So I do have a new un-used sending unit from T. Rutlands that I don't need. Wow it doesn't LOOK un-used in the picture but I assure you it is new and un-used. Image Unavailable, Please Login
Mine does exactly the same thing, but when it seems "dead", tapping on the face of it will always restore normal operation, often after a transient full-scale needle swing. I suspect either the gauge, or more likely, the wiring and connections. These tinned connectors do not work forever. Cleaning and maybe greasing with a PTFE grease to prevent oxidation is a good start to solving a lot of gremlins. Gold contacts would be nice, too. -Forrest
Mine does the same thing, showing 0 and then coming back to live to show normal speed indications. This also happens on my tachometer. Is there a sending unit for the Tach and where are its connections located (for cleaning)?
The sensor for the tach is the Angolar Speed Sensor and you should be able to see it if you stand from the back and look towards the left side of the engine. It looks like the attached photo... I took mine out and cleaned it and the tach stated working again intermittently until I decided to replace the sensor. Image Unavailable, Please Login
I have found that when I drive my 328 eastbound, the speedo does not work and the odo does not change. I checked everything out with the car and discovered the problem was not with the car, it was with the rotation of the earth...the globe's spinning speed was negating my ground speed. So I sleep better now.
