[DeTomaso] Tach Issue ...

[Erik Anderson]

Good evening, folks.

A few weeks ago, I installed a new alternator - the Delco si12 model.  Because this alternator has an integrated voltage regulator, the wiring from the alternator to my MSD ignition is a little different.  Working closely with Jon Haas from Pantera Electronics (what a great guy), I think we have the wiring figured out ... but the weird thing in all of this is that, although my cat starts and runs as strong as ever, the tach does not register a single RPM.

It should be noted that I have a new tach adapter (model 8920) and a new MSD SS blaster.  The wiring for those components were very easy and, with a little (ok, a lot!) of assistance from Jon, I think we have the MSD-to-tach wiring correct as well.  But the tach still won't work.

I have tried almost everything to get it to work: tried a second tach, rewired the trigger wire from the tach adapter to the tach, re-wired the grounds, checked power to the tach ... nothing has worked.

So, I ask ... has anyone experienced this before?  Any suggestions?

Fire away, folks ... and, thanks in advance for any ideas you have for me.

Cheers,

EA #3528