As a C4 owner, I'm trying to help out my brother with his C3 (1980 Coupe). His tach doesn't work. When he turns the ignition off, the tach jumps & stays at 2200 rpm.

the tach / bat markings on the distributor is where the wires go. tach wire may be brown or white and bat wire is usually red. i would check to see if there is supposed to be a tachometer filter on it. ecklers show two different filters for it or it could be the circuit board for it. good luck. eddie208902010-08-25 15:15:03

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the dynamic duo

c3vr life member #97

Check the tach filter first. You can bypass it, and see if the tach works. If it does, then you'll need to replace the filter. If it does NOT work, the problem is usually the circuit board, on the back of the tach gauge.

The tach filter is normally on a wire wire coming from the dist.

Actually, now that I read the post more thoroughly....does the tach actually register any RPMs while the engine is running? If the tach is actually working, but the "problem" is it jumping to 2000 with the key off, that's normal on those cars(with the electronic tach)...If that is the only thing that is an issue, then it's really not an issue at all...it's just how they work. When the key is turned on, then the needle goes to "0", until the engine is started, then it will read engine RPM. Once the key is turned off, the tach needle will jump up like that.
If, however, the tach does NOT work at all with the engine running, then you can start with the tach filter, and go from there.
hth


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