Below is a link to a company that I have orded a tach for my 240D from. The transducer mounts to any injector line and comes with 8 feet of connecting wire. The reading unit is 1.5 inch by 3 inches.
Tiny Tach
Engine RPM to 19,990.
Correct reading regardless of the number of cylinders.
Displays RPM when engine is running.
Automatically displays run-time hours when engine is shut off (and power is still on).
A low cost method of keeping track of engine performance.
Standard wire length is 8 feet.
Accurate means of setting exact engine RPM for proper operation of diesel engines.
Requires vehicle power or external 9 volt transistor battery.
(Replace 9 volt battery only once per year.)
Has job timer and 2 service timers.

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'10 Chrysler T&C Stow-N-Go White. Grandpa's ride.

'13 Chrysler 200 Touring Candy Red. Grandma's ride.

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