OK...while I am (semi) patiently waiting for my Chilton's to arrive, in order to better trouble shoot my tach problem...I would like to know what I can expect if I take the (what appears as a) 10mm bolt out from the center of the circle of the wire harness as it passes through my firewall. Someone had recommended to someone else with a tach problem to check connections as they pass through there.
I am thinking/hoping it will be a plug of sorts that will come apart if I remove that bolt...and allow me to clean up some contacts.
Thanks.

 

Your tach sensor is probly bad.

 

Don't mess with that bolt (there is no reason to). It holds the two halves of the electrical connector together, er, more accurately, keeps them from coming apart over time. You can backprobe the connector if need be to check for signals.

What do you have for test gear to check for a tach signal with? 12V test light? Volt-Ohm-Meter? Oscilloscope?

 

Digital multimeter. I am supposing I am looking for a green wire with a yellow tracer as that is what appears to come off the tach sensor.

And yes, I have replaced the tach sensor...anyone need one for 50$, almost brand spankin' new?