Got the car running right but the MSD is causing my tach to jump all over the place once over 3,000 rpm, I can by-pass the MSD and the tach works fine. I've changed the rev limiter with the same results. Any ideas? Thanks!

 

You're not alone. The philosophy of MSD (Multi-Spark Discharge) inherently causes problems with tachometers since a tachometer counts sparks. Creating multiple sparks of high enough energy to trigger the tach is what an MSD does. You can filter the tach input so that the threshold and/or minimum time base for a trigger is adequate to ignore the "extra" coil primary events, but it may cause problems at higher RPM with a non-responding tach.

 

i had this problem with running my tach off an 6a box... over 6200rpm or so, the tach would jump like cray to 8k and 0...i recently replaced my msd box with a msd dig 6+ box, and tach is dead nuts on...no more jumping...

 

YOu can buy a tach adapter from MSD part nbr 8910 ( I think, doublecheck!)

/N.

 

It looks correct. Thank you Sir!

 

...my factory tach would drop to 0 any time I nailed the gas. Otherwise it would work fine. - My sport comp doesn't seem to care....one day I'll find out if the factory tach in my 96 dash will have it.

 

Does this tach adapter actually work? Has anyone had good experiences with it?

 

yes indeed it does

or the tach filter needs to be removed
the formulas seem to need the tach adaptor
the camaros could get away with the tach filter or the tach adator

pluged right in too