Tachometer Sensor Testing

[Josh]

Tachometer Sensor was easy to remove from top of bell housing and test per the attached instructions. Could have been tested without removing but I wanted to see what the business end looked like and check for any damage or gunk. It was clean but seems to have failed the test, infinite resistance. The plug ends are dirty and a bit corroded so I'll have to clean those up before installing new sensor.

This required a 1 1/8 inch and 5/8 inch open end wrenches and a Volt/Ohm Meter (I used my new Klein CL2000) . An adjustable wrench would have worked well too.

Some quick and easy testing is described here--> VDO Sensor Testing Bulletin

Here's some info from Midtronics, a supplier of these sensors--> Magnetic Pickup Sensors Sales Sheet This literature shows that nominal resistance for Part #5MT-2005B is 690 ohms. Need to figure out if that is what we should see on the resistance test or if the 50 ohms specified in the VDO test bulletin is correct.

The Midtronics Website for even more info.



Also see my post on the VDO Tachometer. (#12 in the thread)

[Josh]

I started searching for a new tach sensor with some googling, no luck there, then a call to Cummins, no luck there but they recommended I call Spartan since the Champion is on a Spartan Chassis. Spartan no longer has access to the part but they were able to tell me that it is a GM Hall Effect Sensor part #340-011E

Well, false alarm, that part # is for a speedometer sensor. Another call to the Spartan parts line and they're digging into the old microfiche for me. Turns out they do have this one, Part #5MT-2005B for a mere $112. They immediately emailed me a picture of it so I could verify it was the correct part. Score! The support at Spartan has always been great.

[Josh]

Sensor installed and working with a little bit of hassle. The sensor is a perfect fit but the plug is a modern (much better quality) weather sealed plug. I decided to clip both plugs off, solder and cover with marine heat shrink tubing.