Dumb Q- New Tach w/ HEI kills engine.... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

72c5 · 06-12-2005, 10:01 AM

Seems simple enough to wire a tach, two leads and a ground.......

I bought an entire new tach dash, this is a Counterpart Automotive job.

Came with a Tach Harness and all........so one lead to bat switched and then the other lead goes that is for the coil, goes to the hei cap tach connection...........no seperate coil w/ hei.

as soon as i connect the tach harness, truck dies???

Yes the cluster has a very good ground......

Any thoughts?

Thanks!

cdowns · 06-12-2005, 10:09 AM

sounds like a bad tack that's shorted out internally

lamar · 06-12-2005, 10:18 AM

Make sure the posts going threw the tach mounting plate are not touch the metal housing( the 2 post on the back with red bushing on them.)

jose · 06-12-2005, 01:12 PM

I had the same problem when i installed my new tach . Come to find out that the posts on the tach were upside down . So when i pluged in the wiring harness the red wire would wound up on the coil side of the tach . Your red wire should go to the positive side on the tach . I switched the wires on the plug in rather than taking the cluster of .

72c5 · 06-12-2005, 06:33 PM

sees like thats what it is....

thx i'll check for a short......

72c5 · 06-12-2005, 10:16 PM

Thanks Guys! That did it, the terminals on the back of the tach were reversed so that the harness went on reversed. I repositioned the terminals and the harness went on correctly......

Thanks!

06-12-2005, 10:01 AM	#1
72c5 Registered User Join Date: Dec 2003 Location: Boston Posts: 311	Dumb Q- New Tach w/ HEI kills engine.... Seems simple enough to wire a tach, two leads and a ground....... I bought an entire new tach dash, this is a Counterpart Automotive job. Came with a Tach Harness and all........so one lead to bat switched and then the other lead goes that is for the coil, goes to the hei cap tach connection...........no seperate coil w/ hei. as soon as i connect the tach harness, truck dies??? Yes the cluster has a very good ground...... Any thoughts? Thanks!

06-12-2005, 10:09 AM	#2
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	sounds like a bad tack that's shorted out internally __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

06-12-2005, 10:18 AM	#3
lamar Registered User Join Date: Apr 2004 Location: Covington,Ga Posts: 453	Make sure the posts going threw the tach mounting plate are not touch the metal housing( the 2 post on the back with red bushing on them.) __________________ 72 C-10

06-12-2005, 01:12 PM	#4
jose Registered User Join Date: Feb 2001 Location: Salem , Oregon 97301 Posts: 1,796	I had the same problem when i installed my new tach . Come to find out that the posts on the tach were upside down . So when i pluged in the wiring harness the red wire would wound up on the coil side of the tach . Your red wire should go to the positive side on the tach . I switched the wires on the plug in rather than taking the cluster of . __________________ 68 GMC 4x4 SWB jose6772@yahoo.com

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06-12-2005, 06:33 PM	#5
72c5 Registered User Join Date: Dec 2003 Location: Boston Posts: 311	sees like thats what it is.... thx i'll check for a short......

06-12-2005, 10:16 PM	#6
72c5 Registered User Join Date: Dec 2003 Location: Boston Posts: 311	Thanks Guys! That did it, the terminals on the back of the tach were reversed so that the harness went on reversed. I repositioned the terminals and the harness went on correctly...... Thanks!



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