the transducer bolts around one of the injector lines. Reads the pulses from the pump.
For you first gen owners that don't already have a tach, Here is one for you!
I just talked to the guy from tinytach and he said they are coming out with a new diesel tiny tach that is BACKLIT !!!!!! And instead of the nonreplacable internal battery that can eventually go dead,They say after 5 years, will be a flash memory that requires only vehicle power. Effectivley making the tinytach last as long as the vehicle. They are 1.5" by 3".Here is a link to the site,
http://www.tinytach.com/tinytach/diesel.php They do not list this new tach yet on the website. The guy i talked to said to call back in a couple weeks to order one. He said they would be about 20$ more than the current diesel Tinytach, which is priced at 65$. I will definatly be ordering one as soon as i can!
ez