So this is a bit strage. I went into the store for about 30 min, and when I came out and started my car, it idled rough and lopy and the tack was not working. I shut the car off, and started it again, the same thing. I gave the car some gas, the tac jumped up and the car smoothened out and everything seemed to work just fine. What could be causing this. This is a 91 speed density 305 TPI that I had just recently professionally rebuilt.
Thanks

 

The white wire coming off of the coil.

I'd check to see if that wire is pinched some place, shorting out the coil signal. If it is, it's bound to happen again.

 

There are two sets of wires that are connected to my coil. One of them is a heavier gauge white and pink, the other one is a smaller gauge white and pink that plugs into the coil with a separate, smaller connector. Is the thinner set of wires that relays the signal from the coil? Also could this be causing the slight miss and intermittent hesitation problems that I have been experiencing recently.
Thanks

 

The connector that goes back to your car's wiring loom, not the one that goes over to the distributor.

The tach is not driven by the ECM. It's just like tachs frorm decades ago that connect to the - terminal of the coil. The ECM gets it's own separate reference signal straight from the distibutor.

If your tach or tach wiring is flaky it can cause problems. If it is supplying an alternate ground path for the - side of the coil throught that white wire you won't get spark. As with all things electrical something "flaky" or "intermittent" can happen which can leave you pulling you hair out over stuff like this.

 

so if the white wire is grounded for some reason that will cause the car to idle poorly or not at all ?

im trying to mentally follow the signal from the rotation of the engine, dist spins which creates a signal that goes to the coil asking for spark which is then delivered to the plug. Can you describe the path using the wires/colors?

 

Well,
I will look a bit more carefully to find out exactly what set of wire goes where. There are two sets of wires, both pink and white, that go into the ignition coil, and also the thick wire that goes to the distributor cap. The wires that lead to the connector of the thinner gage white and pink wires seem to be pinched right at the connector. I will replace that connector by soldering and wrapping a new connector on there. The thicker pink and white wires seem to be fine. but I am not sure exactly where each set of wires go.
If the white wire is for the tachometer signal, what is the pink wire for?

 

i think the pink wire is for the ignition switch

 

Yes, the big pink wire is 12V+ constantly any time the ignition switch is in the run or start positions.

Yes, if you were to ground the smaller white wire going back to your tach you would get no spark. The coil would be constantly charging, but never firing. It fires when the ignition module in the distributor breaks the circuit (denys a ground path to the - side of the coil). If there is an alternate path to ground on the - side of the coil (through your tach or it's wiring) voltage will continue to flow through the coil and it won't fire.