Extra Part on Ignition System

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gzig5

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I just got the car a couple months ago. Got it started so it would idle and it's been down since then while I repair some rust and replace the fuel tank and line. I notice that I seem to have an extra part connected to the ballast resistor. Looks like a cap or condensor from a points type ignition and it is wired into the plug on the ballast resistor and then grounded under the bolt that attaches the electronic ignition control box to the firewall. The car is a 73 Cuda with a 340, with electronic ignition. I'm curious as to what it's purpose might be? Is it benign or could it cause an issue? The wiring harness is a mess and it's obvious a previous owner was a hack with the wiring. I'm a bit hesitant to touch anything at this point because it was running, but I have a new engine harness on hand to install once it is back down on it's wheels.

cap.JPG


cap2.JPG
 
That looks like a condenser to prevent interference to radio signals, they would usually be bolted to the coil.
 
That looks like a condenser to prevent interference to radio signals, they would usually be bolted to the coil.

That sounds plausible. It's been few years since I've played with one of these old cars but I remember that trick to filter electrical noise. I'll leave it for now and take car of it when I redo the wiring. No radio in the car so I don't know if it is effective or not.
 
That looks like a condenser to prevent interference to radio signals, they would usually be bolted to the coil.

It may be that some previous owner was trying to get rid of some radio noise, and or perhaps had a CB/ amateur radio
 
To make the car's radio quieter, you would install it on the upstream side. Since it is installed on the downstream side, which feeds the ECU, it would prevent the ECU from being messed up by interference from something else, like the CB radio which 67Dart273 mentions. Those were very popular in the 1970's after the movie Smokey and the Bandit. Perhaps the engine stumbled every time he keyed "Breaker, Breaker, ...".
 
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