Tach not working

[dboyw]

My coworker picked up a 99.5 F250 Pretty decient shape for a 11 year old work truck. Only has 98000+ on her.

The tach has not worked since he bought it. My first though was the sensor in the rear diff, but that does the speed, not the tach. What do we need to look at for the tach? Everything else in the dash works fine.

Thanks

 

[rammertide07]

I may be wrong....hopefully someone that has experience with 'em will explain better. But I think there is a spring or a belt that works the tachometer.

 

[Tail_Gunner]

The sensor in the rear end has nothing to do with the tachometer. The tach has electronic input, not mechanical.

I'm wondering more along the lines of a CPS.

What I'd do is hook an analyzer up and see if it is getting a RPM reading. If it is, it might be a bad tach gauge. If not, it might be a bad wire or a CPS.

 

[atk]

the sensor in the rear end has nothing to do with the tachometer. The tach has electronic input, not mechanical.

I'm wondering more along the lines of a cps.

What i'd do is hook an analyzer up and see if it is getting a rpm reading. If it is, it might be a bad tach gauge. If not, it might be a bad wire or a cps.

x2....

 

[BIG JOE]

x2....

X3.

Joe

 

[rammertide07]

Learning something new everyday

 

[trackspeeder]

The gauge is bad. The tach reading comes from the CPS. Goes to the puter, then makes its way to the tach.

 

[JLDickmon]

here ya go..
tach is run by the gauge buffer

 

[dboyw]

Thanks everyone.