tach filter ? is that to make your tach compatible with HEI?
what does AmerAutowire tech support have to help on this?

 

Is your tach connected to the tach terminal on the cap.

 

My understanding is that the tach filter will make the factory tach work with HEI.
I installed the tach filter in line and plugged it into the tach terminal on the Distributer.
What I don't know is if there's different tach filters and if I just got the wrong one.

 

Did the tach work before you installed the HEI? What make of HEI?

Really look closely at the connector on the HEI. If you miss the male pin or it is bent,, it will not make contact properly.

 

Where did the tach filter come from?

If it's the basic GM style design of tach filter--did you ground it properly? The factory ones had an "IN" wire, and "OUT" and the body of the unit needs to be mounted to chassis ground.

 

I got the filter off of ebay but I don't remember from what company. Are there different filters? Maybe I bought the wrong one.
It has the in and out wire. The body of the filter has a mount that I bolted to the intake. It's an aluminum intake but that should be good enough for the ground right?

 

I just went back and looked. The tach filter I bought is for a 75-89 Corvette. Replaces GM part number 14020025.

I do see another one for 76-81 camaro, firebird and Chevelle. Maybe I need to buy that one.

What do you think?

 

Does anyone know if there's a certain tach filter that I need to buy or if any tach filter will work? If there is can you let me know where to get one

 

what tach do you have ???[part#] to research your tach's spec's...

 

I'm still using the factory tach. I appreciate the help. I'm stumped.

 

I'm still using the factory tach. I appreciate the help. I'm stumped.

just being clear = you have a factory 69 chevelle dash mounted tach.
and you need a filter that will work with this stock factory tach?

 

That is correct. I need a tach filter that will make my factory tach work with my new HEI ignition.

 

Scott,can you answer these questions from me and Coppertop.

 

I'm wondering if that tach previously worked correctly with standard points ignition?

 

Sorry. I read back through the string of posts and here's answers to the questions. Let me know if there's anything else you need to know.
The tach did previously work prior to the HEI ignition install.
The distributor is a Street Fire HEI by MSD part number 8362.
The tach filter I bought is for a 75 - 89 corvette (gm# 14020025).
It is bolted to intake so I think the ground is ok.
My tach is the factory tach.

I did just finish restoring the car so I'm wondering if maybe a wire behind the dash is not right. I will check the ground behind the gauges.

Thanks again

 

What fixed the problem? I have a factory tach in a 69 Chevelle using factory wiring harness going to a stock HEI distributor and my tach reads about half the the RPMs. Once it gets to about 18-1900 it really wont go any higher. I have researched the tach filters and don't mind buying what it takes but hey that's what these forms are about right? ANy help would be appreciated.

 

I have the same problem with my 72. I have an HEI distributer and my factory tach doesn't work either. I baught the same 75-89 corvette filter on ebay. Didn't work for me either. I installed and grounded it per the instructions. Need suggestions.