bad engine grounds or ,high resistance electrical connections,
like coil wires, or a defective coil, and worn ignition wires,
bad, battery and engine electrical connections and faulty grounds are primary sources for this problem,
the more ohms resistance,
in the ignition, system's wiring,
and component connections,
the higher the heat in the ignition module during operation,
and the more likely it is to fail.
even a single cylinder's high resistance ignition wire ,broken connector,
or the coil wire , or defective ignition coil causes issues with high heat.
and lack of thermal grease under the ignition
module, WILL EVENTUALLY CAUSE IT TO FAIL
read thread
btw if the vettes still having that issue
Id suggest replacing the ignition module, distributor cap, rotor and coil,
as the component age and wear are rather frequently the root cause of that intermittent ignition /HEI related problem
in C4 corvettes that are well over 24 years old
but obviously make sure the parts selected & bought match the year corvette you use them in
http://garage.grumpysperformance.co...istributor-ignition-modules.16056/#post-96896
https://www.rockauto.com/en/catalog...1,ignition,ignition+control+module+(icm),7172
https://www.rockauto.com/en/catalog...350cid+v8,1041231,ignition,ignition+coil,7060
https://www.rockauto.com/en/catalog...0cid+v8,1041231,ignition,distributor+cap,7120
very good
https://www.google.com/search?q=art...me..69i57.240303j0j4&sourceid=chrome&ie=UTF-8
good
Arctic Silver 5 High-Density Polysynthetic Silver Thermal Compound AS5-12G - OEM
good
https://www.amazon.com/dp/B019BZENY...tWxSNqn1YeeooBP4D.BQ&slotNum=18&tag=wepcus-20
in the distributor are very common problems,
http://garage.grumpysperformance.co...ouble-shooting-rebuilding-hei-ignitions.2798/
http://www.superchevy.com/how-to/67498-hei-coils-modules/#ixzz1WXIRF3d2
https://www.autozone.com/repairguid...n-HEI-System/Pickup-Coil/_/P-0900c1528025f555
get out the multi meter, test the coil, battery connections and voltage and ohms resistance.
http://www.harborfreight.com/5-in-1-dig ... 98674.html
all the ignition wire should read under 100 ohms per foot in length.
and yes even some new ignition wire does not meet that requirement
https://www.gmcmi.com/wp-content/uploads/2014/05/HEI-Testing.pdf
https://www.chevyhardcore.com/news/hei-distributor-troubleshooting-with-performance-distributors/
https://www.autozone.com/repairguid...eshooting-the-HEI-System/_/P-0900c15280083b2c
https://www.hemmings.com/stories/article/the-lost-art-of-servicing-gm-hei
https://chevythunder.com/hei_troubleshooting_page_2_coil_.htm
https://isavetractors.com/blog/do-you-keep-burning-out-ignition-coils-here-is-why/
many aftermarket ignition modules are not well made,
the OEM, AC DELCO are generally better quality
https://www.rockauto.com/en/moreinfo.php?pk=1393025&cc=1041220&jsn=2241&_nck=Ekt6BqBF1pxfnyh/V1qBw9dg1uWzEnsiBhKYyGSvvw/BlImwaASI+DKrtPUjRWIoazOBafTB/6oiGzhri6OXell+64oL+OBsctO4Iqc7XgJ3cmVIGiHr85wNtdWwrrikvhQkT8WZIMZFjztSzlJwc0AY1uXwF6GqNey01LWXoIto4w4eABriiSq7ssozi3+B5wGe9BdO8tBPab0Yw+G1xj+MhuTH4BsT946Zw38ubaEAJ+U1VhlBa3ZQHXwS1irTm2WXMXPBrU7UVztooKDjS+cvULy13qHNTB/50U0vzu/cQj2BGsNg+qAJo1z7ez1W/fGzhZaXO2Ex6vNDP+xziShbuVUeb8kH8zT4uCwaICi5/Vm4J6vRNA==
https://www.doityourself.com/stry/how-to-test-an-ignition-module
http://garage.grumpysperformance.co...ouble-shooting-rebuilding-hei-ignitions.2798/
http://garage.grumpysperformance.co...blem-with-my-87-c-4-corvette.5055/#post-89786
http://garage.grumpysperformance.co...your-c4-corvette-runs-badly.15212/#post-87228
http://garage.grumpysperformance.com/index.php?threads/1990-corvette-no-spark.13857/#post-70895
http://garage.grumpysperformance.com/index.php?threads/multi-meters.3110/#post-71867
http://garage.grumpysperformance.co...grease-for-ignition-modules.10748/#post-46944
like coil wires, or a defective coil, and worn ignition wires,
bad, battery and engine electrical connections and faulty grounds are primary sources for this problem,
the more ohms resistance,
in the ignition, system's wiring,
and component connections,
the higher the heat in the ignition module during operation,
and the more likely it is to fail.
even a single cylinder's high resistance ignition wire ,broken connector,
or the coil wire , or defective ignition coil causes issues with high heat.
and lack of thermal grease under the ignition
module, WILL EVENTUALLY CAUSE IT TO FAIL
read thread
trouble shooting & rebuilding HEI ignitions
if your ignition is working correctly your getting a hot blue spark, thats got a noticeable audible snap to it if you test an ignition wire by removing it from a plug temporarily and holding it about a 1/3" from a ground like the block,a quick check of your shop manual for the correct advance...
garage.grumpysperformance.com
btw if the vettes still having that issue
Id suggest replacing the ignition module, distributor cap, rotor and coil,
as the component age and wear are rather frequently the root cause of that intermittent ignition /HEI related problem
in C4 corvettes that are well over 24 years old
but obviously make sure the parts selected & bought match the year corvette you use them in
http://garage.grumpysperformance.co...istributor-ignition-modules.16056/#post-96896
https://www.rockauto.com/en/catalog...1,ignition,ignition+control+module+(icm),7172
https://www.rockauto.com/en/catalog...350cid+v8,1041231,ignition,ignition+coil,7060
https://www.rockauto.com/en/catalog...0cid+v8,1041231,ignition,distributor+cap,7120
very good
https://www.google.com/search?q=art...me..69i57.240303j0j4&sourceid=chrome&ie=UTF-8
good
Arctic Silver 5 High-Density Polysynthetic Silver Thermal Compound AS5-12G - OEM
good
https://www.amazon.com/dp/B019BZENY...tWxSNqn1YeeooBP4D.BQ&slotNum=18&tag=wepcus-20
in the distributor are very common problems,
http://garage.grumpysperformance.co...ouble-shooting-rebuilding-hei-ignitions.2798/
http://www.superchevy.com/how-to/67498-hei-coils-modules/#ixzz1WXIRF3d2
https://www.autozone.com/repairguid...n-HEI-System/Pickup-Coil/_/P-0900c1528025f555
ignition wires & getting the header clearance
Good spark plug wire usually has less than about 400-500ohms ohms resistance per ft. Your correct that less resistance tends to allow more SPARK energy a crossed the plug gap, which in most cases is best set in the .040-.045 range in my experience, for HEI ignitions and .030 plug gap for a...
garage.grumpysperformance.com
http://www.harborfreight.com/5-in-1-dig ... 98674.html
all the ignition wire should read under 100 ohms per foot in length.
and yes even some new ignition wire does not meet that requirement
https://www.gmcmi.com/wp-content/uploads/2014/05/HEI-Testing.pdf
https://www.chevyhardcore.com/news/hei-distributor-troubleshooting-with-performance-distributors/
https://www.autozone.com/repairguid...eshooting-the-HEI-System/_/P-0900c15280083b2c
https://www.hemmings.com/stories/article/the-lost-art-of-servicing-gm-hei
https://chevythunder.com/hei_troubleshooting_page_2_coil_.htm
https://isavetractors.com/blog/do-you-keep-burning-out-ignition-coils-here-is-why/
many aftermarket ignition modules are not well made,
the OEM, AC DELCO are generally better quality
https://www.rockauto.com/en/moreinfo.php?pk=1393025&cc=1041220&jsn=2241&_nck=Ekt6BqBF1pxfnyh/V1qBw9dg1uWzEnsiBhKYyGSvvw/BlImwaASI+DKrtPUjRWIoazOBafTB/6oiGzhri6OXell+64oL+OBsctO4Iqc7XgJ3cmVIGiHr85wNtdWwrrikvhQkT8WZIMZFjztSzlJwc0AY1uXwF6GqNey01LWXoIto4w4eABriiSq7ssozi3+B5wGe9BdO8tBPab0Yw+G1xj+MhuTH4BsT946Zw38ubaEAJ+U1VhlBa3ZQHXwS1irTm2WXMXPBrU7UVztooKDjS+cvULy13qHNTB/50U0vzu/cQj2BGsNg+qAJo1z7ez1W/fGzhZaXO2Ex6vNDP+xziShbuVUeb8kH8zT4uCwaICi5/Vm4J6vRNA==
https://www.doityourself.com/stry/how-to-test-an-ignition-module
http://garage.grumpysperformance.co...ouble-shooting-rebuilding-hei-ignitions.2798/
http://garage.grumpysperformance.co...blem-with-my-87-c-4-corvette.5055/#post-89786
http://garage.grumpysperformance.co...your-c4-corvette-runs-badly.15212/#post-87228
http://garage.grumpysperformance.com/index.php?threads/1990-corvette-no-spark.13857/#post-70895
http://garage.grumpysperformance.com/index.php?threads/multi-meters.3110/#post-71867
http://garage.grumpysperformance.co...grease-for-ignition-modules.10748/#post-46944
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