Update on inoperative 1993 VR speedo. After I posted on May 10 this year about replacing the tiny cog in my speedo assembly and finding that the speedo no longer worked either, I sent the full cluster to Lonsdale st auto electrics in Dandenong after a referral. The tech found that the tiny tooth broken off the cog had fallen into the mechanism and had jammed up the speedo... If you replace this cog, I suggest you make sure nothing in the housing will fall out (assuming you still have the main cog out), turn the unit upside down and give it a shake to see if the tooth (or teeth) come out. If they don't, you might have to look into the mechanism to make sure broken teeth aren't jamming the mechanism.
When I put the cluster back in (carefully) and took the car for a drive, the speedo STILL wasn't working ("Oh no..."). Following a discussion with my mechanic who checked the sender unit on the trans, I decided to send the unit back. Unfortunately the tech was away sick, so I had to wait a week to get it back. Put it back in after he checked it and found it working, and it STILL didn't work... Not happy at all. Another check with the mechanic suggested taking it to the local auto electrician just up the street. After he checked it, he found the sender is working, but the speedo isn't - after I'd just spent some $180 on having it fixed.
The auto elec said that an instrument specialist he uses in Heidleberg said that these speedos can tend to give up in the end and the only real option is to buy another one. He's going to try to source one for me with a warranty. Car has done about 240,000 kms.
Ironically, after recently putting some Xcelplus and Engine Restorer into the oil, I found a significant improvement in fuel economy and an increase in power, but when I picked it up from the elecs and drove it off (engine nearly cold - cold night and morning), it now seems to be a bit sluggish in acceleration. Will put some more injector cleaner into the tank and just hope this solves that problem.
