Tachy-o-meter

[Jake S.]

I got a cluster from a 1994 f-700. Fit right in. But the truck had a 5.9 cummins in it. From the pic, you can see that the tach is different. It only has three connectors on the film in the back. I traced them and one is battery power. one is ground, and one goes to the connector for the stock tach. My question is: Does anyone know how the tach reads RPM's on the F-6-7-800's so I can use this thing?

 

[h2odrx]

i would think if the wires are there and all is stock it should work? when did they put tachs in our trucks?

 

[Jake S.]

I found that that the '83-'86 bodystyle stock tach goes to 4500 and uses four wires. one power, one ground, one going to the sensor on the ip housing, and a return from the housing. So the sensor gets power from the tach itself. I think that the cummins uses a hall effect switch on the crank? It seems that the f-700 tach gets fed a signal from something else. So if ours reads gear teeth, and the cummins uses crankshaft....or alternator? Funny how Ford used the same dashs in the medium-duty's years after changing them in the light-duty's.

 

[Agnem]

Yea that is good to know that an 83 dash can be found all the way to 94.

I'd think your screwed on the tach. As was mentioned the correct tach counts gear teeth. I don't think the cummins will match up. On the plus side, you could build an adapter if your skilled in electronics.