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Speedometer and tachometer

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536 views 4 replies 3 participants last post by  Jim G 
#1 ·
1985 Alfa spider is the chassis, the Bosch fuel injection and ignition are gone. I do not want an 85mph speedo. Tachometer will need to be pre Bosch ignition.

thanks
 
#2 ·
I have both from a '71 Spider if that will work.
Cheers, Jon
 
#3 ·
The tach doesn't care about the fuel system. Yours should be electronic. Which gets its signal from the negative side of the ignition coil. Besides When Alfa did away with the mechanical tach in 79 or 80 they also did away with the gear that drives the tach drive. You would have to pull the timing cover off an replace the idler gear for the timing chains with an earlier one to use a mechanical one.
 
#5 ·
On the Bosch system there are several wires on the negative side of the coil. One goes to the tach and one or two others are sending signals to the computer.

Your tach is independent of the Bosch fuel system.
 
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