Tachometer Troubleshooting
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Elder User
Joined: Apr 2015
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From: Boston, KY
Tachometer Troubleshooting
I am having issues getting my tach to work. Right now, when I turn the engine on, the tach turns backwards and settles at 6500 rpm where it stays, regardless of engine speed. I have a duraspark 2 setup. There are a lot of splices, but I think it is wired correctly - not positive though. Below are some pictures
There is a positive wire coming from the starter relay that splits into two wires. One goes to the + terminal of the coil, the other goes into the red wire on the two-wire harness at the ICM
For the other harness, three wires are going to the distributor, and one is going to the negative terminal of the coil (which should be sending a signal to the tachometer). There are two extra wires coming out of the harness that are part of another harness, but aren't hooked up to anything. What are those for?
Here is the wiring diagram I've been working from. Is there something under the dash I should be checking out? Any help is greatly appreciated. I would really like a functional tachometer!
http://webpages.charter.net/1bad6t/D...rkWiringFW.gif
There is a positive wire coming from the starter relay that splits into two wires. One goes to the + terminal of the coil, the other goes into the red wire on the two-wire harness at the ICM
For the other harness, three wires are going to the distributor, and one is going to the negative terminal of the coil (which should be sending a signal to the tachometer). There are two extra wires coming out of the harness that are part of another harness, but aren't hooked up to anything. What are those for?
Here is the wiring diagram I've been working from. Is there something under the dash I should be checking out? Any help is greatly appreciated. I would really like a functional tachometer!
http://webpages.charter.net/1bad6t/D...rkWiringFW.gif
Fleet Owner
Joined: Aug 2005
Posts: 23,667
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From: Easton,Ks
Duraspark 3 system:
/
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
I see now it is a 1987 so it would not have had the Duraspark 3 system.
Sorry I had just got up and was not reading the year and so on.
I do not know if you have a stock tach or a after market tach.
Did it have a 460 carb engine in it before?
If the tach is wired right and it is doing what it is doing then I would say replace the tach.
Sorry I had just got up and was not reading the year and so on.
I do not know if you have a stock tach or a after market tach.
Did it have a 460 carb engine in it before?
If the tach is wired right and it is doing what it is doing then I would say replace the tach.
Thread Starter
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Elder User
Joined: Apr 2015
Posts: 613
Likes: 0
From: Boston, KY
I see now it is a 1987 so it would not have had the Duraspark 3 system.
Sorry I had just got up and was not reading the year and so on.
I do not know if you have a stock tach or a after market tach.
Did it have a 460 carb engine in it before?
If the tach is wired right and it is doing what it is doing then I would say replace the tach.
Sorry I had just got up and was not reading the year and so on.
I do not know if you have a stock tach or a after market tach.
Did it have a 460 carb engine in it before?
If the tach is wired right and it is doing what it is doing then I would say replace the tach.
The tach is factory. So far, I've only gotten the speedo and volt meter to work. It's a gauge by gauge project trying to get them all to work. I'm just trying to find out if something like a short would cause the needle to move but then stay put at a certain RPM. When I got the truck, the tach didn't do anything at all, so I suppose what I've got now is an improvement......
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