90-91 tach filter?
Burning Brakes
Joined: Nov 2000
Posts: 1,012
Likes: 1
From: Bowie MD
I know you will get conflicting advice on this subject. However, I bought my 1990 NEW, and even saw it built. Therefore with authority will tell you my 1990 L98 had NO tach filter. I thought I was having a tach filter problem because my tach on my dash was reading alot higher than it should be. Thats when after being advised here to install a new filter, I found I did not have one. I replaced my Gauge cluster and the problem was solved. If you had one, it would be about a foot from the distributor close to the drivers side firewall. (on the white wire I think). That is why Ecklers or GM does not sell one.
Chris
Chris
Thread Starter
Racer
Joined: Jan 2005
Posts: 315
Likes: 0
From: tomahawk wisconsin
I have a kinda square little box off the tach input about a foot down in the harness.I have done a little research on it and it looks like the filter on the 92 on. its not the barrel type filter.I am wondering what would happen if I just removed the filter? also if that didnt work would the one off a 92 work?
thanks again
thanks again
Instructor
Joined: Feb 2005
Posts: 210
Likes: 0
From: Racine WI
89 Tach Filter
When I get on it hard, and fast, the tach on my 89 tops out about 35-3700. I was told this was the tach filter. So now the questions are, do I have one, if I do where is it, if I don't what do you suggest?
Thanks guys.
Thanks guys.
Le Mans Master
Joined: May 2000
Posts: 7,033
Likes: 12
Originally Posted by GreyHairedTopGun
When I get on it hard, and fast, the tach on my 89 tops out about 35-3700. I was told this was the tach filter. So now the questions are, do I have one, if I do where is it, if I don't what do you suggest?
Thanks guys.
Thanks guys.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
Originally Posted by GreyHairedTopGun
So now the questions are, do I have one, if I do where is it, if I don't
what do you suggest?
what do you suggest?
Dist Cap marked 'Tach' and follow the white wire out of sight behind
the driver's side head you will feel the Tach Filter. Look closely
between the head and firewall and you will see another white wire
passing through a male/female connector before entering the harness
bundle.
Mid America carries filters: there is one style for the pre '84 and a
different style for the '84-'89.
If Hippy is correct and you have an aftermarket ignition or you are
using an aftermarket tach, then you might want to check with MSD
to ask about which of their Tach Adapters (8910, 8913, 8920 or ...)
might be suitable for your requirements.
.
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Advanced
Joined: Feb 2005
Posts: 77
Likes: 0
From: N. Tonawanda NY
I have the factory electrical service manual for 1990 and the wiring diagram shows no tach filter. The white wire comes from the distributer directly to the instrument cluster, all white wire. The sevice manual has a brief mention that the signal is produced by the ignition system. It dosen't mention any servicing of the tach it's self. If the tachs in our cars are off or wrong I would belive that the instrumet cluster would have to be replaced.
Melting Slicks
Joined: May 2004
Posts: 2,524
Likes: 10
From: Lufkin Texas
St. Jude Donor '05-'06
Originally Posted by corvette1990
I know you will get conflicting advice on this subject. However, I bought my 1990 NEW, and even saw it built. Therefore with authority will tell you my 1990 L98 had NO tach filter. I thought I was having a tach filter problem because my tach on my dash was reading alot higher than it should be. Thats when after being advised here to install a new filter, I found I did not have one. I replaced my Gauge cluster and the problem was solved. If you had one, it would be about a foot from the distributor close to the drivers side firewall. (on the white wire I think). That is why Ecklers or GM does not sell one.
Chris
Chris
Not sure what it's purpose is, I just know my 90's tach is working great without it. I replaced the instrument cluster with a GM refurbished unit when I had tach trouble and now my tach works great, without the filter.Here's mine not serving much purpose.
Team Owner
Joined: Sep 2002
Posts: 22,209
Likes: 12
From: OBAMA IS HITLER
when the tach in my '90 went haywire, i replaced the tach filter with a used one i bought from a salvage yard. the problem was corrected with the replacement filter.
by the way, the tach filter in 90/91 is specific to those years. they are out of production and unavailable new, anywhere. the only means of support right now is via a salvage yard (and most likely will remain that way forever).
i still have my stock ignition.
by the way, the tach filter in 90/91 is specific to those years. they are out of production and unavailable new, anywhere. the only means of support right now is via a salvage yard (and most likely will remain that way forever).
i still have my stock ignition.
Thread Starter
Racer
Joined: Jan 2005
Posts: 315
Likes: 0
From: tomahawk wisconsin
Originally Posted by Hot Rod 90
when the tach in my '90 went haywire, i replaced the tach filter with a used one i bought from a salvage yard. the problem was corrected with the replacement filter.
by the way, the tach filter in 90/91 is specific to those years. they are out of production and unavailable new, anywhere. the only means of support right now is via a salvage yard (and most likely will remain that way forever).
i still have my stock ignition.
by the way, the tach filter in 90/91 is specific to those years. they are out of production and unavailable new, anywhere. the only means of support right now is via a salvage yard (and most likely will remain that way forever).
i still have my stock ignition.
Burning Brakes
Joined: Nov 2000
Posts: 810
Likes: 3
From: Austria
i found this..i built the curcuit, but havent tested yet...
http://www.corvetteforum.net/c4/marc...achfilterj.jpg
i too have a 90, tha tach reads high at idle, about 1200rpm when idling with 800, more interesting, when i rev the engine, tach stops at 4000rpm, and when i shift, it jumps around ....
http://www.corvetteforum.net/c4/marc...achfilterj.jpg
i too have a 90, tha tach reads high at idle, about 1200rpm when idling with 800, more interesting, when i rev the engine, tach stops at 4000rpm, and when i shift, it jumps around ....
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
www.rodneydickman.com/CorvetteTachFilter.html
You can try someone like this, the filter should reduce the spiking in the line. When I asked this quite awhile back many told me they removed with no problem.
The intersting thing here is when I went to get a part number for it, the GM dealer pages show no part there ???
You can try someone like this, the filter should reduce the spiking in the line. When I asked this quite awhile back many told me they removed with no problem.
The intersting thing here is when I went to get a part number for it, the GM dealer pages show no part there ???
Last edited by mseven; Jan 23, 2006 at 06:55 AM.
Cruising
Joined: Jan 2019
Posts: 13
Likes: 2
Tach filter
I have the factory electrical service manual for 1990 and the wiring diagram shows no tach filter. The white wire comes from the distributer directly to the instrument cluster, all white wire. The sevice manual has a brief mention that the signal is produced by the ignition system. It dosen't mention any servicing of the tach it's self. If the tachs in our cars are off or wrong I would belive that the instrumet cluster would have to be replaced.
Instructor
Joined: Jun 2012
Posts: 185
Likes: 24
From: Tennessee
Tach filter
My 1990 tach was inaccurate reading 1500 rpm from actual, .before I pulled the engine. after engine installation it stopped working completely, I went to check tach connection and found filter wire broken. Ordered a new one form Zip corvette installed it and still no tach reading.
pulled out the cluster using a digital volt meter set to AC volts with engine running checked voltage at terminal B10 I read 6VAc so signal was coming in to tach but not working. Sent it to bantee.com for replacement he's very knowledgeable he changed out all the bulbs cleaned connections and replaced a electronic filter inside the cluster. After reinstalling it's been working great.
pulled out the cluster using a digital volt meter set to AC volts with engine running checked voltage at terminal B10 I read 6VAc so signal was coming in to tach but not working. Sent it to bantee.com for replacement he's very knowledgeable he changed out all the bulbs cleaned connections and replaced a electronic filter inside the cluster. After reinstalling it's been working great.
Last edited by vettespecial; Jan 4, 2020 at 10:36 AM.
