tachometer reading wrong

[WZ JUNK]

New tach on an engine with a Mallory coil.  Engine runs fine but tach does not read correctly.  The tach works correct on another car.  Is this a sign the coil is bad?  What else could be wrong?

John

[Jokester]

Usually the ground.  Ground it directly to the block, not the dash or a fender.

my 2 cents.

.bjb

[enjenjo]

http://www.malloryperformance.com/pdf/TachAdapters.pdf

See of that helps.

[WZ JUNK]

http://www.malloryperformance.com/pdf/TachAdapters.pdf

See of that helps.

That is pretty good stuff but I do not think it is applicable as the car had a working tach previously.  

I will dig around a little more.  I have some information on checking the coil with an ohmeter.  I will see how that goes.

John

[WZ JUNK]

Talked to Autometer.  This combination of distributor and coil required an inline resistor.  Fixed it.

John