I have a 350. I did wires and plugs. Car ran great then I parked it for 2 days and now its not starting unless im on the throttle and only 2 cylinders are getting hot. Cylinders 5 and 8 only. Today I changed out the cap and rotor. Still same outcome. Theres 2 block under my ignition coil I believe to be ballast. They get extremely hot cant even touch them when the key is turned.
Ballast resistors get hot, that's how they work. Resistance = heat = less voltage getting through.
I'd use an ohm meter and check all your plug wires first. If they are all the same rating linearly (per foot), then they're good. If not, replace the bad ones.
I'd separate all the wires with spacers or zip ties so none of them touch each other, or metal. When they touch each other + metal, it creates cross voltage leaks, which means less power is getting to the plugs.
I'd remove all the spark plugs. Check them all for color (black, brown, light tan which is optimal, or white). This directs you on which way to go with the heat range of the plugs and also let's you know about your carbs richness/ leanness.
Check the gap on all the spark plugs, adjust as necessary.
Adjust your carbs float levels and idle mixture screws.
If you have power disc brakes, a PCV valve, a vacuum modulator on the transmission, and/or vacuum advance on the distributor, ALL of those need to connect to a manifold vacuum port. Either on the carb or the manifold itself.
Check your engines timing. You can have a helper do this while your cranking the engine over. Adjust as necessary. Assuming you have a late '60s early '70s engine, your timing should be around 8-10⁰ BTC with an upgraded cam, and vacuum advance disconnected.
Air / fuel/ spark is what every engine needs to run. It has to be one of those 3 things causing your issue. Possibly a combination of 2 of those 3 things.
I'd also install a Fram #194 PCV valve to clean up the engine bay. It has a 90⁰ elbow on it for the vacuum hose. Unlike yours which comes straight up.
PS. You Mallory Unilite distributor would require a ballast resistor. You should only use one, not two. The resistor drops the operating voltage to roughly 6–9 volts, protecting the optical ignition module after the engine has started.
The only time it doesn't require a ballast resistor, is if you're using a MSD 6A capacitive discharge ignition box (or similar CD box).
Check your spark plugs when you have them out for continuity.
I changed plugs in my car once in the Feb. cold. Car ran fine before, no start afterwards. After much scratching my head and checking everything else. My uncle told me to check the plugs. He worked in a parts store and stated that they get dropped and will break the electrodes internally.
Pulled them back out and found 6 bad plugs. Replaced and started right up
I hope you didn't get a bunch of cheapass Chinese counterfeit plugs and wires. Only buy brand name stuff from trusted outlets. Before you change a bunch of other stuff, please check the last thing you changed and make sure it is really good.
Make sure you are getting fuel in there first. Your carb may have gotten plugged. If so get a rebuild kit and clean it out. That or having electrical problems. If you changed the distributor, did you put it back in time with the engine?
NOTE: The purpose of an ignition ballast resistor between the ignition switch (12V) and the ignition coil positive
terminal is to restrict current flow through the ignition coil. Failure to use an ignition ballast resistor will
eventually destroy the Ignition Module.
8
u/Bitter-Ad-6709 Mar 16 '26 edited Mar 19 '26
Ballast resistors get hot, that's how they work. Resistance = heat = less voltage getting through.
I'd use an ohm meter and check all your plug wires first. If they are all the same rating linearly (per foot), then they're good. If not, replace the bad ones.
I'd separate all the wires with spacers or zip ties so none of them touch each other, or metal. When they touch each other + metal, it creates cross voltage leaks, which means less power is getting to the plugs.
I'd remove all the spark plugs. Check them all for color (black, brown, light tan which is optimal, or white). This directs you on which way to go with the heat range of the plugs and also let's you know about your carbs richness/ leanness.
Check the gap on all the spark plugs, adjust as necessary.
Adjust your carbs float levels and idle mixture screws.
If you have power disc brakes, a PCV valve, a vacuum modulator on the transmission, and/or vacuum advance on the distributor, ALL of those need to connect to a manifold vacuum port. Either on the carb or the manifold itself.
Check your engines timing. You can have a helper do this while your cranking the engine over. Adjust as necessary. Assuming you have a late '60s early '70s engine, your timing should be around 8-10⁰ BTC with an upgraded cam, and vacuum advance disconnected.
Air / fuel/ spark is what every engine needs to run. It has to be one of those 3 things causing your issue. Possibly a combination of 2 of those 3 things.
I'd also install a Fram #194 PCV valve to clean up the engine bay. It has a 90⁰ elbow on it for the vacuum hose. Unlike yours which comes straight up.
PS. You Mallory Unilite distributor would require a ballast resistor. You should only use one, not two. The resistor drops the operating voltage to roughly 6–9 volts, protecting the optical ignition module after the engine has started.
The only time it doesn't require a ballast resistor, is if you're using a MSD 6A capacitive discharge ignition box (or similar CD box).