I found the following article on the UK 300ZX site and have posted it here in case it is of value to someone. Maybe worthy of inclusion in the Tech pages. All credit to JeffTT from the UK Tony A lot of owners have issue with the speedo, power steering, auto box change etc. All of these are related in as far as they are part of the speed sensor circuit, having seen many owners pondering on if the speed sensor is at fault then take a look at the picture below. The speed sensor is rare in as far as it can be seen to be faulty by just looking at it provided of course you know what to look for. The photo actually shows autobox sensors but the manual box sensor has the same issues. The unit is a small pulse generator, as the cog is turned by the gearbox the stator is turned within the field windings which produces a small ac voltage of around 1 to 5 volts and as the unit is very unstressed there is very little that can go wrong with it. However the unit is held together by the black plastic end cap, this end cap is where it all goes wrong, for reasons unknown the caps start to come adrift as seen in the photo. This loosening of the end cap allows the stator shaft / field windings to move out of line not by much but enough to stop the output been produced. Annoyingly as the cap originally starts to slowly moves out, the shaft end float is still small enough for it to move in and out of the correct position and so causes it to work intermittently. So armed with this information all you need to do if faced with this problem is get the car jacked up and take a look at the end cap on the sensor, if it looks like the faulty one in the picture simply apply a layer of epoxy resin to the edge of the cap and push it back in, yes that simple, no need to even remove it, and you will have one fixed sensor for a tube of glue. Hope that is of help. Jeff TT
hmm I should go look at my old one that failed , see if its like the photo. Mine seized up causing the plastic gear to be sheared off ... so maybe different. [/QUOTE]
I have now fixed the problem that was casuing what I originally thought was a speed sensor issue. I replaced the sensor and still no joy. I then pulled the wiring back out to where I could see it as it is usually hidden away by the transmission. I removed the split loom and found a dodgy old repair on one of the wires, using one of those cheap plastic joiners. One of the wires came off in my hand when I touched it. I cut that section of wire out, soldered in a new piece of wire the same guage and no more porblems thus far. In hindsight I probably should have looked for somethig like that first so if anyone is having the speed sensor issues, e.g. no speedo, no power steering and no cruise, have a look at the wiring first. In relation to the photo's above, both my original speed sensor and the second hand one I purchased both had the black case protruding. It will slide back in without any great issues. Tony
Neither of my speed sensors had the black rear protruding , so that wasn't my issue. Good to see you got yours sorted though [/QUOTE]
