MSD 6M-2L BOX need ground ?
 

Let’s talk about the MSD 6M-2L box

Last night a want to start my engine on the stand .
i dont mounted my box on the braket so i put a old shirt on the bloc for not scratch the paint an drop the MSD box on it . Plug the black wire on the ground and the red on positive and 12V on the ignition .. the engine wont start … no fire . After a lot of test i took a wire directly on the corner of the box and go to the negative terminal on the batterie, engine start and run find . Y remove the wire and the engine shut off …

so if it’s normal that the box need to be mounted on as ground surface ? Or me box have a problem ?

Not that I see in the instructions: https://documents.holley.com/6560.pdf

On any MSD or ignition really, the ground supplied to the boxes main black ground wire , ie, common ground, must also be the common ground to the engine. As far as grounding the Chassis, ie, external part of box to engine, absolutely NOT required. Was your engine grounded to main ground, common ground of your power supply, IE same thing boxes main ground was attached to? If NOT, I would ground it all properly.

Yess the black wire on the box is ground directly on the battery terminal . In the boat the box is mounted on the metal braket on the engine and run fine . But if the box does not mounted on the braket will not fire . I need to make the box housing ground to have fire .

when I run engines with MSD boxes on the test stand the box is usually just laying on the ground. if you are having to ground the case then I would say there is a broken ground circuit inside the box.

Not normal then, Ive mounted them away from engine on fibreglass on rubber insulator mounts and they work

ok thanks . So i check for open the box and find the problem or y buy new one

thanks you .

Its a fully podded box so you aren't getting into it like the red automotive boxes. MSD doesn't rebuild them either cause of this. If its new, I'd call them or where go it from and if used, dammit!