69 427 tri-power extremely weak ignition circuit

Q. I have a 69 427 tri-power. I just changed the accelerator cable and then had an extremely weak ignition circuit. I installed a new battery…was due anyway and still weak. I have juice to the alternator, horn relay, starter, and terminal relay on the firewall checked with a test light. Is there a ground wire attached to the gas pedal bracket/linkage I did not connect. Thanks for the help.

A. That tells me that you probably do indeed have a disconnected ground somewhere. That could be physically disconnected or electrically disconnected by wear or corrosion.

We often see various cars with bad accelerator cables due to poor engine ground. On Corvettes you have to check the cable that goes around the engine mount and also check for high resistance in the entire ground circuit. Using a Digital Volt Ohm Meter (DVOM) check for voltage drop across the ground circuit between the battery and engine block during cranking. The voltage drop should not exceed two tenths of one volt.

For what it’s worth you may have had problems for some time and the reason it is showing up now is the new accelerator cable. Many new cables have resistance built in to prevent them from becoming part of the electrical circuit. Older cables often were good conductors and when a ground circuit failed they became an alternate path to ground. Over time this damaged the cable and that meant the possibility of a stuck accelerator.

Originally posted on National Corvette Owner’s Association newsletter http://www.nationalcorvetteowners.com/

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