Tach wire kills engine
Thread Starter
Pro
Joined: May 2006
Posts: 576
Likes: 0
From: Kernersville North Carolina
Tach wire kills engine
What should I look for when trouble shooting the tachometer? when I hook the wire from the tach to my distributor it kills the engine. I have a 68 with a 69 350 sb engine using a gearhead 50K hei dist.
any diagrams would be great.
thanks!
any diagrams would be great.
thanks!
Melting Slicks
Joined: Oct 1999
Posts: 2,581
Likes: 14
From: Tolar Texas
The tach wire on my '80 broke off at the tach filter, shorted out on the intake manifold, and fried the ignition module.
I wonder if your tach wire has a slight ground problem somewhere!?!
I wonder if your tach wire has a slight ground problem somewhere!?!
Safety Car
Joined: Nov 2004
Posts: 4,359
Likes: 57
From: Mundelein Illinois
If the engine kills when the tach wire is connected, the problem you are having is the tach wire at some point is grounding to metal somewhere. You may want to connect a wire to the Tach terminal on the distributor and run the wire over the car and through the drivers window and connect to the tach. If the car runs your existing wire is bad somewhere touching ground.
Thread Starter
Pro
Joined: May 2006
Posts: 576
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From: Kernersville North Carolina
thanks for the tips..i'll give'm a try
yes, i'm connecting it in the noted place on the dist for the tach next to the pwr. i followed the green tach wire through the firewall but could not find a bad spot in the wire... 1 thing i'll do is completely clear the wire's casings to make sure that it is not grounded anywhere. i was also planning, but don't want to, to pull the dash to see if it is the tach itself...i've read here a few times that the dash is a bugger to deal with and was hoping to avoid it
i manually placed the trans in neutral prior to installation. i still need to connect the shifter to the trans.
thanks!
yes, i'm connecting it in the noted place on the dist for the tach next to the pwr. i followed the green tach wire through the firewall but could not find a bad spot in the wire... 1 thing i'll do is completely clear the wire's casings to make sure that it is not grounded anywhere. i was also planning, but don't want to, to pull the dash to see if it is the tach itself...i've read here a few times that the dash is a bugger to deal with and was hoping to avoid it
i manually placed the trans in neutral prior to installation. i still need to connect the shifter to the trans.
thanks!
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
How are you going to install the fork-wont you have to remove the bellhousing?What kind of tach do you have?A 68 has a mechanical tach with a cable.Are you sure that is a tach wire?
Last edited by ...Roger...; Sep 23, 2006 at 11:26 PM.
Thread Starter
Pro
Joined: May 2006
Posts: 576
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From: Kernersville North Carolina
i hope i don't have to remove the bh...??? i was told i wouldn't need to...that the fork is a "fork". it would slide in through the square hole in the bh to capture the clutch bearing. i would just need to place the rubber boot on prior to inserting the fork...is this not right? 
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Thread Starter
Pro
Joined: May 2006
Posts: 576
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From: Kernersville North Carolina
why would hey be in the engine compartment in the center just long enough to reach the dist? ....hmmm...i need to just replace all the wire harnesses...just on a tight budget for now...
Le Mans Master
Joined: Jun 2005
Posts: 5,447
Likes: 3
From: Syracuse NY
Sounds to me like you've got an HEI distributor and as someone else suggested a mechanical tach. Your tach won't work if this is fact.
I'd have thought that $500 broken hood you sold me would have made at least a new harness possible. not that it would do any good in this case.
You might want to get yourself an assembly manual
I'd have thought that $500 broken hood you sold me would have made at least a new harness possible. not that it would do any good in this case.
You might want to get yourself an assembly manual
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Originally Posted by bwellisley
why would hey be in the engine compartment in the center just long enough to reach the dist? ....hmmm...i need to just replace all the wire harnesses...just on a tight budget for now...
Thread Starter
Pro
Joined: May 2006
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From: Kernersville North Carolina
Thanks, guys!
So, I'm taking a break from tinkering with the ride due to rain. Had to push it back into the little garage...just a couple of weeks until we get into our new house!!!
Anyhoo, i found the old dist in a box of parts I was planning to toss. Would it be easier to build this up and place it in the car? It is a mechanical one that the tach cable hooks to...upon searching I discovered that you were right and I found the tach cable, which I thought was the speedo cable, and the cable fits into the old dist.
Or, do I buy electronic guts for the tach? Can I do that? Should I do that? Any suggestions??? Thanks!!!
So, I'm taking a break from tinkering with the ride due to rain. Had to push it back into the little garage...just a couple of weeks until we get into our new house!!!
Anyhoo, i found the old dist in a box of parts I was planning to toss. Would it be easier to build this up and place it in the car? It is a mechanical one that the tach cable hooks to...upon searching I discovered that you were right and I found the tach cable, which I thought was the speedo cable, and the cable fits into the old dist.
Or, do I buy electronic guts for the tach? Can I do that? Should I do that? Any suggestions??? Thanks!!!
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Thread Starter
Pro
Joined: May 2006
Posts: 576
Likes: 0
From: Kernersville North Carolina
whoa! that's expensive!
is there a way to convert the tachometer itself? maybe using a later c3 model tachometer? if not i guess i'll need to re-install the old dist and sell this new one along with the plug wires...
is there a way to convert the tachometer itself? maybe using a later c3 model tachometer? if not i guess i'll need to re-install the old dist and sell this new one along with the plug wires...
