I built a truck for my 16 year old daughter and my Ignition wire gets hot while driving and then it doesn't start unless I jump the wires at the starter. Thoughts please!
We talking about the wire going to the coil from the ignition switch? If so, then it may be a resistor wire to cut down voltage kinda like a ballast resistor. If we talking about the coil wire from the coil to the distributor then you really have me scratching my head.
Circuit is too small to handle the load, poor ground or connection, or if points style ignition and this is the feed, no resistor as mentioned. I'd also check the charging system output. Since you have the time in here and the skills, first place I'd check is the ignition switch itself. I'm sure you will be back to report your findings. This is the basic layout, but shows the Ford relay. Ignore that.
I'll try to be more specific. I only took a quick look today and it seemed like the Alternator wire was getting hot but it could also be the coil wire as well. It has a one wire alternator and an HEI distributer on a SBC. No resistor wire or ballast anywhere in the system.
What size ga of wire on "Stud " Of alternator down to starter stud or bat cable " Hot" .? Should be @ least a #10 ga with 100 amp Alt , When charging what the volts showing 13.7 -14.2 v . Bigger amp Alts can be #8 ga some times #6 ga Key in dash or on column , What size #ga wire powering the Coil on HEI ,? What size ga Ground & Hot to battery, & how far battery from starter?
hot is as a result of resistance to the homotron flow.....'loose', corroded connection or too small of a conductor (wire) can be the culprit good luck
Recent change or since built? Alt wire hot = too much flow (check output) or if just built, too small wire. Direct to battery or routed thru other things? Check other things. Ignition wire hot plus no start when hot still points to switch. Also check alt output and battery condition here. Headers? Check voltage during crank cold and hot.
You have to be way more specific to get any meaningful help. There is no coil wire in your setup (HEI). What happens when it doesn't start? Does the starter turn over? What wires is it you are jumping at the starter? If a wire gets hot during normal operation it means it is too small a gauge to handle the current load. If a connection gets hot, it points to high resistance at that connection.
Scratching at an old memory from the late 80s, check the insulating disc under the coil pack on top of hei, they break down and voltage starts to stray, cooked the ground wire good and proper on mine, replaced the complete cap less the coil and the ground wire needed a chunk replaced as well
Check for ground issues, I always like lots of grounds (body-frame, frame-engine, battery-frame, battery-engine if possible). Also make sure the ground strap/tab is inside the cap and still hooked up to a ground source outside the cap. https://www.chevelles.com/attachments/hei-ground-strap-1-jpg.636404/
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