Tach FIlter
M. Anderson
than the dealership.. On my car, the distributor TACH connecter runs to a
small electrical "tach filter" that mounts to the back of the left head. The
tach filter, in turn, runs into the main wiring harness.
Problem: The wire from the distributor broke off right at the tach filter -
there is no possible way to splice it back in. I called a local dealership,
who identified that this item is called a tach filter, and that the part is
discontinued by GM, so there is no way I can get a replacement. I have
searched Ecklers, and they also offer no such part.
Question 1: If I bypass the tach filter, and connect the tach wire from the
distributor directly to the wire where the tach filter wires into the main
harness, will this cause any problems?
Question 2: What exactly is the function of the tach filter - the dealership
could not tell me.
Question 3: Does anyone have a clue where I can obtain a new tach filter? If
the answer to this question is yes, I guess both questions above can be
disregarded. :)
Any help that anyone can provide would be greatly appreciated.
mrvette
the HEI, which are a complicated mess for a tach to deal with...
so they need to be filtered near the HEI itself for max effectiveness, and
minimum interfearance to radio/etc....
OK so I can't draw easily, but if you understand electronics a bit, I can make
a very crude diagrame.....as follows.....
from HEI tach--> resistor 5.6k ohm----resistor 10k ohm---->to tach input
^ ^
` ____ capacitor _____
____ .1 MFD _____ capacitor
^ 600volt ^ 100pf
100 volt
the carrotts are ^ sign and are a wire to the connections on the resistor
circuit, the ^ below the caps connect together and go to engine ground...
best as I can help you parts are Radio Shack for about 4 bucks total...
solder all connections....
GENE
--
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