Topic: Electronic Tachometer filter
in Forum: C3 Electrical
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MARYSVILLE, WA - USA
Joined: 10/22/2006
Posts: 129
Vette(s): 1976 stingray, L48 COUPE, TH350 Automatic WITH A ZZ4 355 HP 350 C.I. MOTOR, 750 cfm HOLLY, EXTERIOR RED, INTERIOR BUCKSKIN, SMOKE BLACK GLASS TEE TOPS.
My Tach dosen't work and I thought I would start by replacing the filter unit before I buy a new circuit board. Can some one explain how to (or post a picture) hook up the three wire type Electrical Tachometer Filter on my 76 corvette? I purchased it from Ecker's as a low cost version of the original "can" type filter but there are no instructions for installation.
Thanks!
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Lifetime MemberDuncanville, TX - USA
Joined: 11/8/2003
Posts: 20213
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
If the tach doesn't work at all, it's probably not the filter. If it works erratically, or is way off, then the filter would most likely fix it.
Don't have a clue how it would be connected tho...can you post a picture of it, and the wires on it?
If all else fails, holler at Eckler's, and see if they have the instructs that just didn't get shipped with the filter.
Don't have a clue how it would be connected tho...can you post a picture of it, and the wires on it?
If all else fails, holler at Eckler's, and see if they have the instructs that just didn't get shipped with the filter.
Joel Adams
C3VR Lifetime Member #56 
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Former Member
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MARYSVILLE, WA - USA
Joined: 10/22/2006
Posts: 129
Vette(s): 1976 stingray, L48 COUPE, TH350 Automatic WITH A ZZ4 355 HP 350 C.I. MOTOR, 750 cfm HOLLY, EXTERIOR RED, INTERIOR BUCKSKIN, SMOKE BLACK GLASS TEE TOPS.
I jumped the gun as I haven't received it yet from Eckler's and it may come with instructions. A pic of it is available on this link http://www.ecklers.com/search.asp?action=freeSearch&free_text=tachometer&first_answer=49&searchHistory=
Lifetime MemberDuncanville, TX - USA
Joined: 11/8/2003
Posts: 20213
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Appears to be only two ways to connect this one:
#1
The only other way would be swapping the white wires...
#1
The only other way would be swapping the white wires...
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Former Member
Send PM
MARYSVILLE, WA - USA
Joined: 10/22/2006
Posts: 129
Vette(s): 1976 stingray, L48 COUPE, TH350 Automatic WITH A ZZ4 355 HP 350 C.I. MOTOR, 750 cfm HOLLY, EXTERIOR RED, INTERIOR BUCKSKIN, SMOKE BLACK GLASS TEE TOPS.
Now that you look at it, that seems logical. I just don't know exactly how to splice the white wires into the tac and distributer as there is only a plug in to the distributer from the tac. I guess I need to look at the existing filter hookup for a clue. Hopefully the new unit it will come with a picture or schmatic.
Thanks for your help!
Can't you just bypass the filter for a test? Just unplug the filter connector from the distributer and plug the connector coming from the firewall that goes to the filter into the distributer instead.
edit:more specific
My tach (1982) acts like it sticks. It will idle at 800 and go up when I rev the engine and eventually come down, but it seems sluggish.
Could this be the filter or is there a cable that might bind?
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Yelm, WA - USA
Joined: 7/12/2007
Posts: 356
Vette(s): 1979 L82 4 speed Scat 383 crank 190 cc Procomp Aluminum Heads 202 160 stainless valves GM Powder metal rods Speedpro H860CP Hypereutectic pistons 280 cam hydralic HEI Pro comp 1.6 roller rockers Mighty Demon 750 Sanderson CC1AP Hedders.
I found a schematic online for a tach filter but I'm also gonna get the cheap one from ecklers and disect it. If all it is are too resistors inline I'm gonna be upset for paying 30 bucks for one, but if that's the case I will probably start making my own and selling them if anyones interested.
http://temp.corvetteforum.net/c4/1moortym//Pictures/tachfilterj.jpg
Lifetime MemberMoses Lake, WA - USA
Joined: 4/16/2005
Posts: 2134
Vette(s): 1976 L48 4-spd, Mahogany Metalic exterior, Buckskin interior 350ci/350hp, 3rd owner, fiberglass spring, 255/50-16's Torq-Thrust II
I bought one a couple of years ago, don't remember where or for how much but it only had the two wires and a steel case that looked like the original one. The case acted as the ground. I assumed it was a combination of resistors and a capacitor.
When mine quit working the tack became erratic. I would work fine for about the first 15 minutes of run time then started bouncing around and some times would just stop working.
in Forum: C3 Electrical
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