L98 Tach Filter question (not location!)
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Pro
Joined: Jan 2001
Posts: 681
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From: Newton (Wichita Area) Kansas
L98 Tach Filter question (not location!)
I had to start a new thread about tach filters since the last one got filled with car show pics and I didn't want to add to the slow download time for the dial up connection people.
Anyway, when I installed an MSD6AL in my '86 the tach didn't work. I was told that the tach filter needed to be bypassed. I didn't get a chance to run the car without the tach filter because I started my 383 swap at that time (see link in my sig) and the car hasn't been run yet.
My question is: Will removing the tach filter send incorrect engine rpm signals to the ECM? If the tach filter is connected (and the tach isn't working) is the ECM getting a good signal then? If the latter turns out to be the case then I'll just get an aftermarket tach.
Thanks in advance guys (and gals)!
Anyway, when I installed an MSD6AL in my '86 the tach didn't work. I was told that the tach filter needed to be bypassed. I didn't get a chance to run the car without the tach filter because I started my 383 swap at that time (see link in my sig) and the car hasn't been run yet.
My question is: Will removing the tach filter send incorrect engine rpm signals to the ECM? If the tach filter is connected (and the tach isn't working) is the ECM getting a good signal then? If the latter turns out to be the case then I'll just get an aftermarket tach.
Thanks in advance guys (and gals)!
Le Mans Master
Joined: Oct 1999
Posts: 6,366
Likes: 34
Re: L98 Tach Filter question (jmr302)
okay I will try this again.
The tach filter is filtering the signal to the dash. I think the ECM gets its info from a different wire.
Such as I can drive it with a screwed up tach or one that is not connected.
Anyhow, I added the MSD and cut out my tach filter, it runs fine and the tach is accurate.
Hope this helps!
[Modified by bill mcdonald, 6:39 PM 8/20/2001]
[Modified by bill mcdonald, 6:44 PM 8/20/2001]
The tach filter is filtering the signal to the dash. I think the ECM gets its info from a different wire.
Such as I can drive it with a screwed up tach or one that is not connected.
Anyhow, I added the MSD and cut out my tach filter, it runs fine and the tach is accurate.
Hope this helps!
[Modified by bill mcdonald, 6:39 PM 8/20/2001]
[Modified by bill mcdonald, 6:44 PM 8/20/2001]
