Hello everybody:

I picked this lil express tach thinking it would somewhat match the oem gauge design of 1st gen trucks. I have a 92W350 with the tach provision. After going over the info provided on this site about the wiring to the plug, I am stuck with wiring to the tach: I don't know which wires go where. I have inserted a pic of the tach. Anyone would know how to wire it?
Additionally, the bulb is missing: does it require a 194 like the instrument cluster, or another?
Thanks for any info!

 

I have several of those 72-79 era tachs. I'm not too sure it'll work correctlly with the 6cyl. application.
The bulb is a 94 or 194, self grounding push-in socket, the brass stud farthest away from the light socket is ignition signal, the steel stud next to that is ground, and the brass stud next to the socket is 12v+.
I've found these thachs to be slow for a hotrod gas engine, but they may work out for the Cummins. Not sure about the 6cyl. vs 8cyl though.

 

Hey Brutalowner:
As per my PM, here's my ugly labeling of the studs (attached pic). Thanks for indicating what wires to what. I'd really appreciate it, as I'm kinda limited on that front...
Ben

 

That tach is designed to be fed a signal from a gasoline engine ignition coil. The crank sensor on the cummins is an inductive pick-up. The two won't work together. I tried once to make an adapter to drive a Sun tach for a gas engine from an inductive pick-up using an op-amp to bring the signal from the pick up up to +12 peak voltage, but it didn't work. I think those types of tach have some sort of high-pass input filter, so they need a spike in the signal to "count". Not to mention, you would have to multiply the signal by 4/3 to get the tach to read correctly.