Q.#1, How can you check if your tach filter is bad? My tach is a little bouncy and I don't think it's accurate. It sometimes idles low but when I tap the pedal it rises to a more accurate reading.
Q.#2, Where can you buy one? My wire going to the filter at the base is worn and thin.

the filter doesn't have any affect of the tach functioning. i have always removed mine with no problems. they are for frequency sensitive components like the stereo, controller/computer, etc. grasmo.

Thanks Grasmo. What is the real "or factory" intended purpose though?

Thanks Grasmo. What is the real "or factory" intended purpose though?

The tach filter eliminates radio interference caused by the firing impulses in the HEI when the engine is running. Without it hooked up you will usually hear a power surging sound through your radio speakers everytime you hit the accelerator, which can be annoying if you are trying to listen to the stereo. If your car has an ECM computer, the interference can cause problems with it. Not sure if anyone has started making repos of these tach filters yet. Last I heard these are hard to find anywhere except in junk yards.

Jim
'80 Berlinetta