jeffery_1965
New member
- Joined
- May 23, 2008
- Messages
- 1
Being the curious sort that I am, my 1st modification to my JD455 is a tachometer. It just seems natural that you would want to know what rpm you're running as you're mowing away. 
I found a nice tachometer that also has a traditional hour meter, a job hour meter, and two service interval hour meters built in. It's made by Tiny Tach, and comes in two versions for the diesel application, 1/4" and 6mm fuel line. They use a piezo electric transducer to tell when the pressure fluctuates in an injection line, during the injection cycle. It's quite a simple device that only requires switched power, ground, signal, and signal ground. The pictures below should help:
First I made a hole in the dash using a dremel tool and a mill file. It took a bit of time to sneak up on the right size, but it looks pretty good for a hand cut hole.
Next comes sanding off the black paint on the injector line that you want to install the sensor on. 220 grit made quick order and left a nice clean ring of steel.
The sensor is mounted using the two supplied screws, with the red sensor wire going under one of them. The sensor ground wire (white) is connected to engine ground. I used loosened up a 10mm nut on the injection pump,and put the ground terminal under that.
Switched power is pulled from the upper 15 amp fuse using spade connectors. Connect to the lower leg of the fuse.
The ground connection was made to the 10mm bolt holding up the voltage regulator. (under the dash, on the right side)
Fire up the engine and viola, 1240rpm at idle. The picture isn't that great, as the display is very crisp and also has a green back light.
So now I know, it idles at 1240rpm and wide open is 3400rpm. Not that it makes much difference, but it will be fun to play with and see if changing rpms during mowing makes much difference in fuel consumption. Like I said, I'm a curious sort....
Jeff
I found a nice tachometer that also has a traditional hour meter, a job hour meter, and two service interval hour meters built in. It's made by Tiny Tach, and comes in two versions for the diesel application, 1/4" and 6mm fuel line. They use a piezo electric transducer to tell when the pressure fluctuates in an injection line, during the injection cycle. It's quite a simple device that only requires switched power, ground, signal, and signal ground. The pictures below should help:
First I made a hole in the dash using a dremel tool and a mill file. It took a bit of time to sneak up on the right size, but it looks pretty good for a hand cut hole.
Next comes sanding off the black paint on the injector line that you want to install the sensor on. 220 grit made quick order and left a nice clean ring of steel.
The sensor is mounted using the two supplied screws, with the red sensor wire going under one of them. The sensor ground wire (white) is connected to engine ground. I used loosened up a 10mm nut on the injection pump,and put the ground terminal under that.
Switched power is pulled from the upper 15 amp fuse using spade connectors. Connect to the lower leg of the fuse.
The ground connection was made to the 10mm bolt holding up the voltage regulator. (under the dash, on the right side)
Fire up the engine and viola, 1240rpm at idle. The picture isn't that great, as the display is very crisp and also has a green back light.
So now I know, it idles at 1240rpm and wide open is 3400rpm. Not that it makes much difference, but it will be fun to play with and see if changing rpms during mowing makes much difference in fuel consumption. Like I said, I'm a curious sort....
Jeff
