I have installed a couple MSD 6AL boxes over the years that take the RPM rev limiter pills...I just installed a msd 6425 ignition box with adjustable rev limit on a 93 Trans Am, the car ran great before the install, i used the msd harness so i didnt have to cut the coil harness..the car fires up perfectly but will not hit the desired Rev Limit..It doesn't matter what the setting is at it will only hit about 5500 RPM....so i decided to unhook the 6AL and hook it back up like factory and now the car will not start when its hooked up like stock....if i hook up the MSD 6AL box it fires right up but still will not hit the rev limiter...is there an issue with the new 6425 box that will not allow it to hit the limiter but will allow it to start.....AND why will the car not start when the MSD 6425 is unhooked and returned to stock setup.

 

Ever figure this out? I take it your car had the stock tune/rev limiter?

 

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