2nd ign module went out in couple hrs again!!
 

brand new ign modules in my thunderbolt iv ign
port side motor module went out in about a 1/4 tank of gas run time
bought new module and re ran my ground wire for it to the block. ran another 1/4 tank of gas thru it and went out lastnight again! same motor!
i know the ground is good. what else could be making this engines ign module go out with about the same amount of run time on it before it kills it? can the thunderbolt iv ign BOX be going bad or something?
im running new msd high vibration coils
thanks

Where is the module mounted????? The module case and ground wire BOTH need to be grounded.

ign modules in the distributer held down by 2 screws. how do you ground the ign module case? its just held by the screws

Are you sure it's the module?

Quick & dirty test is to disconnect the green/white wire from the amp and touch/rub it to a ground.

This is with the key on and with the coil wire someplace where you can see if it is sparking. And no gas or fumes to ignite!!!

I'm not sure how the ign amp would like those coils but I can't think of why that would affect the module.

This is just a guess, but perhaps the coils are drawing a bit too much current and overheating the module. Try going back to the stock coil on that engine. All of the primary current going to the coil is switched on and off by the module.

It was not a good thing when Merc moved the module from the exhaust elbow to the distributor housing. The housing runs hotter then the elbow which makes it a poor heat sink.

Have you checked the voltage going to it at speed, the alternator may be pushing higher current than normal. I run a 60k volt coil with my IV have been for about five years doubt it has anything tot do with things. Check your main engine grounds, a dirty ground can make an alternator put out higher current.

im going to buy another ign module and swap my coils from motor to motor. maybe i have a bad coil making the module overheat. i did notice that right before it went out that my tach started acting crazy by jumping around. i shut the motors off to dock. then when i tried to start it was toast grounds are all good
maybe i should run a tempary ground wire straight to the battery but i know it cant be.
could the thunder bolt ign BOX be going bad?

keep in mind both motors are running same parts and wired the same but only one motor is burning up these modules

I had an ignition problem and changed the modules and ran for about 15 min and quit like you. My prob was the coil. I think when the coil got hot the ignition would fail. Coil cooled off while I changed the module and ran OK for a few minutes until it heated back up is the only thing we could think of.

Ok, I am confused. I was not reading carefully. Is the problem the sensor inside the distributor or the ignition amplifier which is either on the outside of the distributor or on the exhaust elbow?