MSD tach question
 

Just got all of the wiring done to get my new engine running.

The engine can't be started yet because I sent my oil tank out for a refurb.

I hooked the battery up and verified some hot vs. switched, etc. I thought I had read that with the new digital 6AL that when you turn the key the tach sweeps up and back down. True? Didn't happen though. Does that indicate anything?

Todd

Hard to tell till you start the engine, but some VDO tachs (mostly early) need a MSD tach adapter, some don't.

Actually, realizing the LEDs are blinking then going off. Something else going on looks like.

Todd

A little more info. The documentation I got with the units was not great (didn't even mention model 6425).

In the updated documentation available online it states to the affect -

The rev limit verification is disabled from the factory. With the key in the on position, car not running, the LED will come on and go off and stay off until car is running.

So, you have to specifically enable the tach sweep.

Todd

Sounds like you found the difference, and it is working fine. :)


Sent from my iPhone using Tapatalk

Just to close the loop on this and maybe help others -

There is updated documentation on the MSD web site. My 6425 boxes would have the LED light solid when the key turned to on position, then blink 5 times, then go off. Turns out that they had a firmware update along the way that disabled the rev limit verification (tach sweep to redline). In that configuration, the LEDs blink instead

I followed the procedure to enable it (described in outdated documentation as how to disable default setting), and now my tach sweeps to > 7000 when I turn key to on position.

All is well :-)

Todd