Is this a tach filter?
Thread Starter
Drifting
Joined: Nov 2005
Posts: 1,324
Likes: 5
From: Charlotte NC
Is this a tach filter?
While cleaning up the wiring on my '93 LT1, I found a small box wired into the coil connector. Is this a tach filter or something left over from the past owner's butchering?
Thanks! JG
Thanks! JG
Racer
Joined: Aug 2008
Posts: 301
Likes: 17
From: Toronto Ontario
Yes, that's the tach filter. Mine went bad a few month's back and I wasn't able to find a replacement anywhere online. None of the local parts stores carried them either. My tach readings were bouncing around like a monkey's ball-sack.
I simply removed it and spliced the wire ends together. Problem solved. The tach now responds a lot quicker then before and appears to be a lot more accurate as well ...
Hope that helps.
I simply removed it and spliced the wire ends together. Problem solved. The tach now responds a lot quicker then before and appears to be a lot more accurate as well ...
Hope that helps.
Last edited by LT1*C4; Jul 20, 2009 at 03:28 PM.
Pro
Joined: Mar 2008
Posts: 579
Likes: 2
From: High Bridge New Jersey
Different
Yes, that's the tach filter. Mine went bad a few month's back and I wasn't able to find a replacement anywhere online. None of the local parts stores carried them either. My tach readings were bouncing around like a monkey's ball-sack.
I simply removed it and spliced the wire ends together. Problem solved. The tach now responds a lot quicker then before and appears to be a lot more accurate as well ...
Hope that helps.
I simply removed it and spliced the wire ends together. Problem solved. The tach now responds a lot quicker then before and appears to be a lot more accurate as well ...
Hope that helps.
LT1*C4, how did you access your filter? It seems to be jammed way down behind the distributor with very little room to work...
Racer
Joined: Aug 2008
Posts: 301
Likes: 17
From: Toronto Ontario
edit:
I see you own a '91 L98. The location of your filter must be differed than on an LT1. Since I never had a problem with the tach filter on my last L98 powered car, I never bothered to look and see where it was. Sorry.
Maybe another L98 owner can help you out with that better than I can.
Last edited by LT1*C4; Jul 21, 2009 at 04:53 PM.
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Thread Starter
Drifting
Joined: Nov 2005
Posts: 1,324
Likes: 5
From: Charlotte NC
My cars an LT1 just like "jimg's'93's" and just as the photo's he posted show, the tach filter is easily accessible (at least is was on mine). It's located just off the left side of the coil (closer to the throttlebody). Nothing had to be removed on mine to get access to it. Just pulled it out of the convoluted tubing it was in and cut it out with a pair of scissors. Stripped the ends of the white wires and solder'd them together. Wrapped them up with a piece of electrical tape and stuffed it all back inside the plastic sleaving. The whole process took less than 5 minutes ...
edit:
I see you own a '91 L98. The location of your filter must be differed than on an LT1. Since I never had a problem with the tach filter on my last L98 powered car, I never bothered to look and see where it was. Sorry.
Maybe another L98 owner can help you out with that better than I can.
edit:
I see you own a '91 L98. The location of your filter must be differed than on an LT1. Since I never had a problem with the tach filter on my last L98 powered car, I never bothered to look and see where it was. Sorry.
Maybe another L98 owner can help you out with that better than I can.
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
I see you own a '91 L98. The location of your filter must be differed than on an LT1. Since I never had a problem with the tach filter on my last L98 powered car, I never bothered to look and see where it was. Sorry.
Maybe another L98 owner can help you out with that better than I can.
Maybe another L98 owner can help you out with that better than I can.
Racer
Joined: Aug 2008
Posts: 301
Likes: 17
From: Toronto Ontario
Having said that, if you're not having problems with your tach's readings, just leave it be. Like I always say, if it ain't broke, don't try and fix it.
Thread Starter
Drifting
Joined: Nov 2005
Posts: 1,324
Likes: 5
From: Charlotte NC
Well, funny thing is that my display just happened to go on the fritz the day before which prompted me to check my harnesses, grounds, etc. when I came across the tach filter. I'm still going to keep looking, but as a last-ditch, I may try cutting it out. If it makes no change, I can always splice it back in.
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
p.s.
It's been a few years, but 90 or 91 (i forget which) has a nortoriously horrible tach no matter how perfect all of the components are and it is known to be upwards of 1,000 RPM off of the correct value.
It's been a few years, but 90 or 91 (i forget which) has a nortoriously horrible tach no matter how perfect all of the components are and it is known to be upwards of 1,000 RPM off of the correct value.
Thread Starter
Drifting
Joined: Nov 2005
Posts: 1,324
Likes: 5
From: Charlotte NC
I'm pretty sure my tach is ok. It's my display that's fritzing. It just keeps cycling like it's trying to crack a code or something. Then after about 4 minutes or so, it dies down and displays correctly. When I found the filter near the coil I began doing some more searching and find that display issues can be traced to an improperly grounded coil...total coincidence! So, as said, I'm going to do some more wire checking but I may try bypassing the filter.
