Hei coil

[ELCAM]

The filter has capacitors that go to ground if one or both fail it will prevent the engine from running and will eventually burn up the ignition module from drawing too much current. If they are going bad they will cause it to run poorly and also increase the load.

The factory one looks like this. The aftermarket tachometer will have something similar built into it.

 

[dadep76]

The filter has capacitors that go to ground if one or both fail it will prevent the engine from running and will eventually burn up the ignition module from drawing too much current. If they are going bad they will cause it to run poorly and also increase the load.

The factory one looks like this. The aftermarket tachometer will have something similar built into it.
View attachment 196637

So could it it be a cheap china coil thats a prob?

 

[ELCAM]

If it runs proper without the tach hoked up it is not the coil. Though that coil in the picture has been abused I would not judge by it, might have damaged the amplifier module too.

In GM material it says to never ground the tach terminal it will fail the module in the distributor. (With a point system that was one way to make an ignition interlock just ground the negative side of the coil and the engine wouldn't run. I assume they saw what happened when folks kept trying to use this method with the new system.)

As the capacitors in that filter fail they have less and less resistance to ground until they are just grounding out that tachometer terminal that is where the extra current is being drawn from to burn that wire.

 

[dadep76]

Looks to be aftermarket.... mostly cheap china stuff, but regardless, what brand is it, how old is the coil and by the looks of the wire insulation, too much current flowed through it, like a short inside the coil possibly.

Its a proform coil. I have a new ac delco coil.

 

[Ernest]

Have you had a chance to run that new AC DELCO coil without the tach hooked up and see how the engine runs?

 

[dadep76]

Have you had a chance to run that new AC DELCO coil without the tach hooked up and see how the engine runs?

Nah i got called in to work. Work is interfering w my car time. Lol. Im gonna shoot for tomarrow. Wish me luck.

 

[airboatgreg]

Sounds like a bad plug wire causing a miss burning up the coil. Look at both ends of each plug wire to see if it is corroded or burnt

 

[dadep76]

Have you had a chance to run that new AC DELCO coil without the tach hooked up and see how the engine runs?

I did and ran w a minor miss. I looked at coil and tach wire burned AGAIN. I took it out and found the spring all out of wack. I have new springs and grommets. Would the spring not being straight do it? Spring looks like it was sitting on rubber grommet not making contact to coil.

 

[dadep76]

If it runs proper without the tach hoked up it is not the coil. Though that coil in the picture has been abused I would not judge by it, might have damaged the amplifier module too.

In GM material it says to never ground the tach terminal it will fail the module in the distributor. (With a point system that was one way to make an ignition interlock just ground the negative side of the coil and the engine wouldn't run. I assume they saw what happened when folks kept trying to use this method with the new system.)

As the capacitors in that filter fail they have less and less resistance to ground until they are just grounding out that tachometer terminal that is where the extra current is being drawn from to burn that wire.

I started car and started to run shitty. I looked at coil and tach wire is burned again..tach is not hooked up. The spring is bent over and was resting on the rubber grommet.

 

[565bbchevy]

I started car and started to run shitty. I looked at coil and tach wire is burned again..tach is not hooked up. The spring is bent over and was resting on the rubber grommet.

It is installed wrong, rotor bushing gets installed first in the cap with the spring up then the rubber insulator.

https://www.jegs.com/InstallationInstructions/100/121/121-8225.pdf