78 l82 tach nonsense
Thread Starter
Instructor
Joined: Feb 2014
Posts: 104
Likes: 1
78 l82 tach nonsense
Today I got my circuit card from willcox, replaced the old burnt up one that was pegging past 7k, and would jump around whenever I was braking or signaling.... With the new card it still pins at 7k, but it doesn't jump around as current jumps across circuits... so that leaves the coil off the distributor and the wiring to the tach...
My question is where can I get the coil for the tach?
My question is where can I get the coil for the tach?
Former Vendor
Joined: Aug 2006
Posts: 76,656
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From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Sounds like a wiring issue but if you want to mail the board and tach to me, I'll test the unit assembly.
The only cost is the shipping both ways.
The only cost is the shipping both ways.
Thread Starter
Instructor
Joined: Feb 2014
Posts: 104
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Well it doesn't jump around at all any more, it pins at a consistent voltage, the old card had a huge black spot that encompassed pretty much everything on the right side of the card, so it was toast anyway, my next idea would be the coil mounted to the intake manifold has failed... I hope it's not wiring, I'm an avionics technician in the air force, so wires don't scare me... But I don't want to open the can of worms under the dash just yet, not until I can buy a new harness entirely
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,850
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Well.. good.. most are.. 
The only things left are:
1) A cooked movement, the part the board bolts on.
2) A coil issue
3) A wire issue. ..
I can take the first one out by testing the tach..
The only things left are:
1) A cooked movement, the part the board bolts on.
2) A coil issue
3) A wire issue. ..
I can take the first one out by testing the tach..
Last edited by Willcox Corvette; May 9, 2014 at 08:20 AM.
Thread Starter
Instructor
Joined: Feb 2014
Posts: 104
Likes: 1
What's the analog movement you're talking about? I'll get the tach out to you probably next week, you guys wouldn't happen to carry the capacitor/inductor coil thing attached to the intake manifold would you?
Melting Slicks
Joined: Sep 2004
Posts: 3,221
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From: Northeast
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,850
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
The part the tach board mounts to is the movement. Yes we carry the filter and you can bypass it. I don't think the filter is your issue though.
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Racer
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From: Oakville ON
Thread Starter
Instructor
Joined: Feb 2014
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I got 12vdc from battery, continuity on ground, & the dist. put out a little over 12vdc at idle (in the console), and rose under acceleration... I bypassed the filter, same dist. output... I hijacked 12vdc from the alternator, found a good ground, & connected the dist. Same problem, so that leaves the new card and the tach itself as the source of the problem
Thread Starter
Instructor
Joined: Feb 2014
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Suddenly it decided instead of sticking at exclusively 7000 it would sit around 4500 to 5000, and then move slightly under acceleration until jumping to 7000, the counter balance inside the tach is off... and I broke the needle trying to rezero it, so I'll need to buy a tach either way