Tach inop
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Heel & Toe
Joined: Jan 2017
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Tach inop
I have a tach that worked and slowly went to inoperable. Does anyone know where the tach runs from the distributor mine runs into a wire loom that is almost impossible to get to. Does it run under the wipers to the dash? Trying to see if and where I can by pass the filter run straight from dash to district to see if I can rule out one of them.before I buy filter or send tach out...
Race Director
Joined: Apr 2002
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From: Anaheim CA
I have a tach that worked and slowly went to inoperable. Does anyone know where the tach runs from the distributor mine runs into a wire loom that is almost impossible to get to. Does it run under the wipers to the dash? Trying to see if and where I can by pass the filter run straight from dash to district to see if I can rule out one of them.before I buy filter or send tach out...
Team Owner
Joined: Sep 2003
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I've seen you mention 4+3 so I'll assume early. I'd think with cluster removed you could check at C5 on the cluster connector. You answer Cliff's question and you'll likely get more specific diagnostics. Year I believe matters for other connector connections that could be used. I see perimeter valve cover retention but that along with the carb could mean squat!
***If you have a scanner I believe if you connect to the ALDL and if it sees RPM values you can assume the signal is "in the cockpit" of the car. If you don't dependent upon year you might need to go to a different connector in the cockpit.
***If you have a scanner I believe if you connect to the ALDL and if it sees RPM values you can assume the signal is "in the cockpit" of the car. If you don't dependent upon year you might need to go to a different connector in the cockpit.
Last edited by WVZR-1; Jan 13, 2017 at 08:36 AM.
Thread Starter
Heel & Toe
Joined: Jan 2017
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O hell lol sorry my bad it's 86 worked driving home after bought it but couple days later started to intermittent go to zero now it just stays at zero.. I unhooked battery for a day then hooked back up it worked for 5 min then no more..
Team Owner
Joined: Sep 2003
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Bryan at Batee says these images are from an '86 FSM and if they are then these seem to indicate that the tach signal passes through the C100 directly to cluster. I don't recall the year I looked at earlier and I was actually more concerned with the ALDL. So maybe someone will confirm the wiring from the FSM before I can post back this evening. In this link look at 8A-82-1. Looking at Bryan's documents maybe tach signal at ALDL isn't going to confirm anything.
http://batee.com/corvette/dcrg/wiringdiagrams/
With a hand held TACH/DWELL you could check beyond the filter I'd think and check for signal. Were you able to put your hands on the filter? Rear of LH cylinder head I believe for an '86. This might be the easiest to confirm signal is good to the C100. You don't want to have to go to the C100 either under the hood or in the car.
Last edited by WVZR-1; Jan 13, 2017 at 09:16 AM.
