[Formulabruce]

Originally Posted by JMB36TA

The HEI is connected to the wiring harness .

The HEI runs on 12 Volts. Points do NOT, they run on about 6.5-7 volts. YOu need to make SURE your new fatter HEI ( Pink wire) is connected into the Fuse box on the engine side. Year one makes this wire if you do not have one or a way to do it for the right current. The resistor line in your car has to GO, if you run a HEI ( and want it to run as a HEI with the spark its supposed to have and less load on the supply side + .

[steve25]

This is a very strange issue because that wire only carrys a magnetly triggered pulse that has far less electrical radiation then for instance the spark plug wires themselves !
With the Tack wire unhooked to you hear any minor spark plug firing static in the radios output?

[JMB36TA]

Originally Posted by steve25

This is a very strange issue because that wire only carrys a magnetly triggered pulse that has far less electrical radiation then for instance the spark plug wires themselves !
With the Tack wire unhooked to you hear any minor spark plug firing static in the radios output?

None at all. The radio was perfect without the tach hooked up.

["QUICK-SILVER"]

Originally Posted by JMB36TA

It's a Retrosound Rodando and it's less than a year old. It has bluetooth and USB ports.

Did it ever work right? If it worked and then failed...Have you had any other problems; like over charging?

Found this from 2010 over on Team Camaro. Posting link for info and future reference. May or may not have any relevance to what's going on here.
https://www.camaros.net/forums/19-el...-problems.html

I'd say definately need to find out why the tach lead/coil (-) is turning in to a transmitting antenna when it's hooked up. Could just be a stray spark caused by a plug wire problem. Or maybe a coil ground problem. Either under the dust cap or where it screws down with the radio capacitor inside the distributor.

Going to need a good radio to figure out what's going on..If anything is.

Clay

[george kujanski]

The tach wire has some nasty electrical transients on it with noise going up to hundreds of volts. Tach inputs suppress these transients but the wire itself can be a really good transmitter.

George

["QUICK-SILVER"]

Originally Posted by george kujanski

The tach wire has some nasty electrical transients on it with noise going up to hundreds of volts. Tach inputs suppress these transients but the wire itself can be a really good transmitter.

George

Would a shielded wire help with that? Using distributor ground and tach ground for the ends of the shield.

Clay

[torqhead]

Originally Posted by "QUICK-SILVER"

Would a shielded wire help with that? Using distributor ground and tach ground for the ends of the shield.

Clay

Interesting idea Clay, possibly would help. And you've known me long enough that I'm not bashing or discounting the idea but I gotta believe there's probably something basic going on here. Many of us use HEI hooked up tachs with decent stereo's and don't have this issue.

[JMB36TA]

Originally Posted by "QUICK-SILVER"

Did it ever work right? If it worked and then failed...Have you had any other problems; like over charging?

Found this from 2010 over on Team Camaro. Posting link for info and future reference. May or may not have any relevance to what's going on here.
https://www.camaros.net/forums/19-el...-problems.html

I'd say definately need to find out why the tach lead/coil (-) is turning in to a transmitting antenna when it's hooked up. Could just be a stray spark caused by a plug wire problem. Or maybe a coil ground problem. Either under the dust cap or where it screws down with the radio capacitor inside the distributor.

Going to need a good radio to figure out what's going on..If anything is.

Clay

It was working great until I hooked up that tach.
Interesting read in that link. I don't know if there was a voltage surge that might have caused an issue but I wasn't paying attention to the gauge. I checked the leads with a meter after I started having this problem and everything is within range. I've been paying attention to the gauge and it has gone up to 14 every now and then when I get on it but usually hovers around 11. I have a new radio on the way, not sure if I want to hook up the tach again and take a chance or just leave it out.

[george kujanski]

If the noise is radiated, the shielded cable may help. However, if the issue is a poor ground between the panel metal back to the engine ground it may not help.

The panel metal must have a good ground connection back to the engine ground. Without that, the tach noise current may mix with the radio power return injecting noise into the radio.

The 67 A body dash is a good example...the dash panel to dash/cowl metal connection is primarily thru a metal bracket that attaches the back of the panel metal to the column support. If the panel is ever removed, lazy mechanics either forget or disregard the bracket mounting bolt, eliminating this main ground path. Funny things begin to happen.

As a test, attach a good size wire between the radio metal chassis to a good dash/cowl metal to make sure the radio metal has a good ground path. If the problem goes away, the metal ground path needs improvement.

George