This is a follow up on my question about a 6.9 Diesel tachometer setup. Does anyone know specifically what the signal coming from the diesel tach sensor is? Is it a analog voltage signal or some kind of high rate on/off signal?
The reason I ask is that I want to match this signal output to my gasoline engine tach if possible.
Any suggestions?

 

They are Hall effect sensors..........

http://www.kemparts.com/TechTalk/tt10.asp

 

You sure about that? I've gathered that you are a Ford tech or something, based on your other posts. But there is one thing in the link you posted that seems not to fit with the tach system on the IDI's. Your link says

"All Hall-Effect sensors use three wires to do the job. One wire carries the power voltage and a second wire supplies the sensor ground. Both are supplied by the ignition module or computer. The third wire is the "toggle". This wire is the sensor's output to the computer. The voltage rises, usually to power voltage, and falls to near zero with the movement of the shutter as explained earlier...."

Our tach sensors only have two wires, so I don't quite see how they can be a Hall effect sensor. Maybe you can give some more explanation that will clarify....

 

Cheaper,
The second wire could be deleted since ground is through the engine block.

 

AHHHH! I see! Now if I can just figure out how to convert the signal off the tach sender into something I can use.....