[Darryl]

Well, I finally got around to taking the 968 instrument cluster apart.



Good news is I was able to apply plastic polish to both sides of the plexiglass "window", implement my light tube fix for brighter lights, replaced the OEM 2W bulbs with 194 3W bulbs, and general cleaning of all other bulbs and connections. Upon re-assembly, temp guage didn't work and Engine Oil light was on, but re-seating the left connector remedied those problems. Went for a drive and low and behold, my temp guage no longer falsely pegs whenever it wants to...it appears to have gotten fixed by cleaning the connector up and exercising the contacts. <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />



Bad news is odometer/tripmeter still intermittant. Both gears look great, no broken teeth, all nice and lubed with some good ol' factory clear stuff of some kind, and everything moves freely. On a couple of the other various Odometer/Tripmeter threads, it was boiled down to some kind of stepper IC or motor problem. On yet another thread, it was discovered that there was a burr on one of the number wheels that would lock up the whole thing. So, electrical, mechanical? <img src="/forum/images/smilies/968/huh.gif" class="smilie" alt="" />



The guy that I got my gears from told me a few tricks about the 968 and 993 assemblies...that they need to be super clean and to wiggle the numbers as you reseat the motor during reassembly. I'm going to take everything apart again and explore the mechanics a lot more closely.



Here's my question...of those of us with odometers that work reliably, (are there any?)...does the tenths on the trip meter move smoothly (it does on my 944) or does it appear to click its way around? What's it supposed to do? I drove Mark's cab last weekend and IIRC, his appeared to click. If it's supposed to move smoothly, my guess would be a piece of something somewhere that jams things up. If all else fails, anyone have any first hand experience with speedomter repair shops for our 968 VDO beast?



Very curious about this now...I'll keep everyone informed.



- Darryl

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[sasilverbullet]

Well before mine quit the other day, it was very smooth and reliable up to 162K miles.

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[944/84]

Darryl --



My tenths wheel clicks as it rotates. Very regular, clock-like clicks.



Bill T.



Here's my question...of those of us with odometers that work reliably, (are there any?)...does the tenths on the trip meter move smoothly (it does on my 944) or does it appear to click its way around? What's it supposed to do? I drove Mark's cab last weekend and IIRC, his appeared to click. If it's supposed to move smoothly, my guess would be a piece of something somewhere that jams things up. If all else fails, anyone have any first hand experience with speedomter repair shops for our 968 VDO beast?



Very curious about this now...I'll keep everyone informed.



- Darryl

[/quote]

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[prj24149]

Darryl, My plastic window needs polishing. what did you use to clean/polish this plastic?

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[Darryl]

[quote name='prj24149' post='37242' date='Jun 20 2007, 11:09 AM']Darryl, My plastic window needs polishing. what did you use to clean/polish this plastic?[/quote]



On the instrument cluster "window", I use Meguire's PlastX in the white bottle. It is available off-the-shelf. For more serious scratches or hazing, NOVUS makes 3 different grades of plastic polish that you can find on-line. Lots of folks use NOVUS-2 for the rear window on the cabriolet. My guess is that the PlastX is equivalent to NOVUS-1.



Back on topic, I was hoping more people would chime in on whether their odometer tenths wheel was smooth or "clicky"... <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" />



- Darryl

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[Mark]

I'll try and look at the other car sometime this weekend.

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[mike]

[quote name='Darryl' post='37253' date='Jun 20 2007, 04:20 PM']Back on topic, I was hoping more people would chime in on whether their odometer tenths wheel was smooth or "clicky"... <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" />[/quote]



Mine is smooth on both my 944S2 with 156K miles and my 968 with 56K miles.



mike

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[Tom in Austin]

My tenths clicked ... when it worked. I have the same issue you do, I've replaced the small gear but after putting all back together, still not working

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[Darth Vadar]

I have a spare Speedo pulled from a nice parts car, showing 55K and change. Can't guarantee that it works but sounds like it would be a better bet than one that flat doesn't!



Has anyone priced a new Speedo thru Porsche? Last time I checked, I think they wanted $550.00 of thereabouts...



Make me some offers on this used one! If it doesn't work, it won't cost much to ship it back to me...

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[Kim]

On my coupe the "tenths" rolls smoothly. On the cab it clicks. Both are 1992s. Both work. Go figure.

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[Allen1322]

Mine clicked intermitantly and then eventually stopped altogether. I replaced the gear even though the original looked perfect. It still doesn't work.



It sounds like these speedo's have a problem with the stepper motor. I would assume that it is supposed to roll smoothly. Stepper motors are supposed to step (click) in small enough intervals that they appear to roll smoothly. If something is wrong either mechanically or electrically, it could cause the motor to take larger steps and become a noticible 'click'.



I talked with someone either on here or on Rennlist who had this problem and was doing pretty extensive testing on it (he was an electrical engineer). But he never found the problem. So I gave up on fixing it and decided to do all of my maintenence based on age, not mileage.



I drive less than 10k a year and figure I'll just do oil twice a year, wash K&N once a year, plugs, wires, cap, etc, every few years, and Timing belt stuff every 3 years. I hope that I will never have to sell the car, so I'm not all that worried about future buyers and explaining why the car has said 56k miles for the past X# of years.

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[Darryl]

[quote name='Allen1322' post='37406' date='Jun 25 2007, 12:19 PM']Mine clicked intermitantly and then eventually stopped altogether. I replaced the gear even though the original looked perfect. It still doesn't work.



It sounds like these speedo's have a problem with the stepper motor. I would assume that it is supposed to roll smoothly. Stepper motors are supposed to step (click) in small enough intervals that they appear to roll smoothly. If something is wrong either mechanically or electrically, it could cause the motor to take larger steps and become a noticible 'click'.



I talked with someone either on here or on Rennlist who had this problem and was doing pretty extensive testing on it (he was an electrical engineer). But he never found the problem. So I gave up on fixing it and decided to do all of my maintenence based on age, not mileage.



I drive less than 10k a year and figure I'll just do oil twice a year, wash K&N once a year, plugs, wires, cap, etc, every few years, and Timing belt stuff every 3 years. I hope that I will never have to sell the car, so I'm not all that worried about future buyers and explaining why the car has said 56k miles for the past X# of years.[/quote]



My guess is the stepper motor too. I haven't done as exensive testing as James, but I also have EE background. I don't know if these are obtainable or not. I may contact a speedo shop that I was referred to and see what their prognosis may be. Not sure I want to spend a ton of money unless it's a 100% fix once and for all - especially since the speedometer works. I tend to agree about just doing maintenance based on time, but it still irritates me! I don't plan on selling the car either, but it makes me wonder how many miles were on the car when I bought it... <img src="/forum/images/smilies/968/huh.gif" class="smilie" alt="" />



- Darryl

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