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Discussion Starter #1
I replaced the clutch on my 1987 Spider Veloce and after re-assembling and test driving, noticed that the speedometer, when at a stop, stays on about 13mph. Never goes to 0. Onec over 13, it seems to be accurate however, but it does seem to fluctuate up and down about 5mph when holding speed. After about a week, my wife noticed that the odometer was not turning when she reset the trip odometer to 0 and it never moved. She then noticed the odometer itself was not moving. Any recommendations or pointers would be a great help! Don't want to end up with a low mileage 1987 that has a defective odometer that brings into doubt the actual low mileage!
 

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But Mad North-Northwest
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If you look, there's a pin that the speedo needle sits on at rest. It's not supposed to go to zero.

Sounds like one of your odometer drive gears has failed. Only fix in that case is disassembly and replacement (if the part is still available) by a speedometer guy.
 

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Mook21...beginning in 86, Alfa uses a cable, pulse generator and electronic attachment to the speedometer head.
Your first step should be to determine if the cable is turning between the transmission and the pulse generator. It could be that the cable is kinked or its ends have become rounded in the trans or pulse generator. simplest fix with a new 16.00 cable. Assuming the cable is ok....the pulse generator plug connection should be checked, then the function of the generator, then the connection behind the monopod dash to the speedometer.
If all that is in order....your speedometer head may be the trouble. It will require that you remove it and have it rebuilt at a speedometer shop.
 

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Discussion Starter #4
the Speedometer is still working, just starts once the car gets moving faster than 13 mph. I unscrewed the cable from the transmission housing to check if there was a kink or problem and am able to turn it by hand easily, so I screwed it back into the transmission and it fully seated. When I re-installed the transmission after changing the clutch, I did stress the cable some while shoving the transmission back up into the car, raising, lowering, raising, etc to get everything properly lined up. Not understanding how the pulse generator works, would something like that potentially damage the cable or cause problems with the pulse generator? Also, is the pulse generator the unit on the firewall on the drivers side where the speedo cable comes up from the transmission? Any suggestions on how to test it? The speedometer and odometer worked fine before I changed the clutch...
 

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Check the cable's other end at the generator.....see if the end is still squared off or worn round. This can effect performance. Check the plug connection. Yes, it is located there...follow the cable up from the trans. Check for wear or kink of the cable where it travels thru a support attached to the steering box. They can kink just below the support bracket. The insulation may be worn at this point. The generator is easy to remove.....one screw. Holds it to the bracket. Undo the cable again at the trans and trying turning the cable from the trans end while someone watches the top end. A speedo shop may be able to check the generator. They are not cheap....if you can find one.
 

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Discussion Starter #6
Revisiting speedometer problem ... 87 spider

I have my spider on the market in classifieds and am having trouble selling because of the issue above about how the speedo works (though seems about 10 mph off running 65 and the needle bobs some) but neither the tripmodometer nor the overall odometer works. Checked both cable ends and they are good. Good connections.

I have read that there is a gear on the speedometer that wears out for the odometer that could allow the speedo to work but the odo to not work. Anyone have experience here because I don't want to pull the dash if this is chasing something that does not exist? Is there a way to check output from pulse generator? By the way, I checked and cleaned the connections there. What should I look for in terms of output? Was thinking to put rear on jack stands and run in first to do troubleshooting, but need to know what to look for from pulse generator. Any help appreciated.

Mark
 

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On your 1987 Spider, the speedometer and odometer are both activated by an electronic pulse generator that is located next to the clutch master cylinder in the engine compartment. The impulse generator is driven by the mechanical cable attached to the transmission. If either the speedometer or the odometer is functioning, it means that the cable from the gearbox to the impulse generator is working, and the impulse generator is also operating correctly. So if your speedo needle advances when the car is moving, but the odometer or the trip meter does not advance, you have an internal problem with the speedometer unit, possibly a broken plastic gear tooth on the trip meter or odometer. If that is the symptom, it can only be corrected by extracting and disassembling the mono cluster.
 
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