Tach Filter

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Mar 10, 2006 | 12:19 AM

Eric the Ricer

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Le Mans Master

Joined: Jun 2005

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From: Beyonce > Taylor Swift - Welcome to the good life!

St. Jude Donor '07

Tach Filter

Ok my tach hasnt worked since i bought the car, and now i really want it to start working. I guess its just the tach filter, and ive been looking for one, but madvet says it only goes up to 89? Sent them an email but havent gotten a return on it yet. Anybody change theirs out with the 89 one? 90 VERT A4.

heres the link to the filter
http://www.madvet.com/shop?frame=3.4167

Mar 10, 2006 | 12:29 AM

VtVette

Melting Slicks

Joined: Mar 1999

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From: Las Vegas Nevada

On my '86 (harness) the connector that plugs into the tach filter is the same connctor on the tach filter than plugs into the distributior. So, you can remove the tack filter and plug the connector that plugged into the tack filter right into the distributor cap. Several people here have done this and some have reported that the tach actually seems more accurate with the filter removed. I don't know for sure if the '89 is the same but if it is it's a simple way to tell if your peoblem is actually the tach filter before going out and replacing it.

hope this helps,

Mar 10, 2006 | 11:30 AM

rick lambert

Le Mans Master

Joined: Oct 2003

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From: seattle WA

Something else you might want to look at, from Gordon Killebrew. He says alot of tach problems can be caused by water getting into the bulkhead connection by the steering column. The tach pins are on the bottom row of the connection. When you remove it you should see some black looking gunk-that's an anti corrosive-leave it in, but if you see a greenish/white look that indicates water getting in, just blow it out-he says the gen. never sealed the connection and advices to seal the top and sides.Also make sure your cowl drip tube is not directed at
the connection.

I never have seen my tach filter-but it does work great and just plugs into the dist.

Mar 10, 2006 | 04:28 PM

Biff Buyer

Racer

Joined: Sep 2005

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From: Wauseon Ohio

the tack filter is a son of a gun to get to. so you can run it without the filter?

Mar 10, 2006 | 05:37 PM

MR NICE

Drifting

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From: Downriver Mi.

My tach lights up but it does not regester anything ,could this be the filter?can I bypass it? What about a test for the filter?Thanks

Last edited by MR NICE; Mar 11, 2006 at 09:04 AM.

Mar 11, 2006 | 10:09 AM

MR NICE

Drifting

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From: Downriver Mi.

Mar 11, 2006 | 10:49 AM

rick lambert

Le Mans Master

Joined: Oct 2003

Posts: 6,130

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From: seattle WA

Read my above post-per Gordon Killebrew " Most Common Causes of a Tach Malfunction-Water in the bulkhead connector". That's #1.
2 Defective tach filter,3 Tach filter not grounded, 4Engine not grounded to the uniframe 5 Grounded wire going from the dist. to the tach filter 6 Grounded wire going from tach filter to bulkhead connector 7 Grounded wire in the dash going to the cluster 8Defective cluster.
I know there are testing procedures or trouble shooting guides in his book-which I have, but haven't seen anything about testing the filter itself! Someone said they run theirs fine without a filter-I don't see how that is possible because the signal coming from the dist. before the filter it's a linear signal-a wave form that's very erratic-after going thru the filter it becomes a square wave which smoothes out the signal.
Gordons book it cheap-about $30 and has the trouble shooting guide for the tach-but do yourself a favor and check the bulkhead connection first.