Printable Version of Topic

Click here to view this topic in its original format

914World.com _ 914World Garage _ Tach wire at coil kills engine

Posted by: surfdogskier May 18 2020, 05:42 PM

Hey Guys,

So none of my needle gauges are working. Well, the tach does sort of. I turn the key and it buries all the way to the right. I know the purple/black wire from the coil should be going to the Tach. When I connect it to the negative side of the coil, my engine dies. I can't even start it with it connected. When I disconnect the wire from the coil, she fires right up.

So, is my tach fried or something else. My speedo does not work or my gas gauge. However, the illumination lights work and the signals, high beam lights on the gauges.

Looking for answers.

Thanks,
Jason
1972 1.7, carbed.

Posted by: GregAmy May 18 2020, 06:32 PM

You sure you have it connected to the correct side? The tach goes to the "1" terminal, not the "15".

Posted by: Spoke May 18 2020, 06:59 PM

Disconnect the wire at the tach and see if it does the same thing. I had a similar experience and removing the tach wire at the distributor allowed the engine to run normally.

I disconnected the wire at the distributor and measured its resistance WRT to chassis and got a very low resistance (short). Disconnected the engine harness from the relay board and still got a low resistance. For some reason, the wire in the engine harness was shorting to ground. Ran a new wire from the distributor to the relay board connector and all was fine.

Posted by: jim_hoyland May 18 2020, 08:01 PM

Could the tach wire be grounding out ? I had one do that

Posted by: Beebo Kanelle May 18 2020, 10:02 PM

Its either one of two things: either the coil is wired backwards or, the tach is wired backwards

Posted by: surfdogskier May 19 2020, 08:54 AM

Thanks for the input guys. I will tinker with it this evening and post back with my findings.

Posted by: VaccaRabite May 19 2020, 01:02 PM

Yup, if you ground your coil from the TACH wire you will get no spark and the motor will immediately die.

Zach

Powered by Invision Power Board (http://www.invisionboard.com)
© Invision Power Services (http://www.invisionpower.com)