The wire broke off of my tach filter. I checked the local GM dealer and this part is discontinued.
I checked it out with my mult-meter and it showed a value of 17K ohms. I went to Radio Shack to find a suitable replacement but they didn't have what I needed and none of the employees knew anything about electronic comonents. (I don't know enough about them either!)
What is this electronic part called? It basically acts like a resistor doesn't it?
Where can I buy the correct automotive replacement part? How much are they?
What generic electronic part can I use to replace it?

The wire broke off while I was doing a test drive about 5 miles from the house. The car sputtered and died.
One of my neigbors stopped and helped me get it running again. Luckily he had a spare ignition coil and module.
As I sat there broken down, GM service manual in hand, I read on the first page in the distributor section, "DO NOT LET THE TACH WIRE GROUND OUT. THIS WILL CAUSE FAILURE OF THE COIL AND OR IGNITION MODULE".
Yup... they're right. It killed my coil! :smash:
Learn something new every day!!! :D

 

So far, this is all that I have found related to tach filters.

Ecklers
PART# 39248
Tachometer Filter, 75-82
$59.99 EA.
http://www.ecklers.com/product.asp?d...&pf%5Fid=39248

Rodney Dickman’s Fiero Accessories.
Fiero Engine Tach Filter (V6 or L4):
Price: $17.50 ($1.00 S&H)
http://www.execpc.com/~rodney1/tachfilter.htm


Once I figure out exactly what “bulk” electronic part that I need, I will be able to put one together without it costing much at all.

I’m hoping someone here has either put one together from scratch or knows where to buy one really cheap.

I wonder if the tach filters are different on 4 or 6 cylinder engines?
:confused:

 

I always thought that was a capacitor. I took mine off a long time ago (tach works just fine without it). I think it is actually the factory noise filter though. Hopefully someone can clear this up for sure!

Rob

 

An 83 Z-28 or a an 84 Monte SS and anything in between has the same filter right by the fire wall.
Has the same part# as the vette.
Get to the junk yard. :crazy:

 

Mike,

You can build a replacement for about $3.00 out of parts from Radio Shack. Here is a schematic I snagged from a post by Zwede a couple of months ago. I made one and it works great, I put the components inside a plastic Smint's box, painted it black and mounted it on the firewall with the wire for the tach running through it. Don't worry if you can't find the exact components, anything close will work. The filter is just a little band pass filter that smooths out spikes in the signal by filtering via capacitance.




[Modified by Smokehouse69, 1:54 PM 8/19/2001]

 

Thanks Smokehouse69.
I printed out the diagram and plan on using it. That should save me a few $$$.
:cheers:

 

I just finished building the “tach-filter” using the diagram that Smokehouse69 posted. The parts cost $6.77 at Radio Shack. It could have cost even less but each of the resistors came in a packs of 5 and the capacitors came in packs of two.
It works just fine.
Thanks for the help Smokehouse
:cheers:

 

I do not see any schematics. Can someone repost them please?

 

Marcus, this thread is almost 20 years old! Doubtful these guys are even still on here!
a new tach filter is about 30 bucks from Zip. Just buy one.

 

Gimme a sec. I'll go get the schematic.

 

Marcus Medina
below is the drawing and pay attention and/or recognize the old terminology for microfarad:

https://www.corvetteforum.com/forums...post1545463876

I made one ages ago for a couple of dollars when radio shack was around. Did not need it anymore after I started getting the tach input from the MSD-6 box.