factory tach

[spencermumma]

Just bought a factory tach wondering how I can hook it up in my non intercooled cummins where they never came with the tach option?
Spencer

[gobigorgohome]

mine had the factory tach. it was reading off the vibration damper that had a notch in it. ran over the engine into the dash and was mounted above the dash on the left side of the steerign wheel. a good place for it too out of line of sight but close enough to see well. worked good. one time it didnt wanna read correctly but after shuttin thte trk down and startin it back up it worked fine

[spencermumma]

I don't have any of the wiring.harness other than the tach and harness on the tach

[gobigorgohome]

i dont see why a guy couldnt make a harness for it as long as you could ccome up withthe plugs to do it with. sensor is 2 wire but idk what the tach is, i would guess 4 or 3

[RumbleFish]

Iirc it's 4 wires. Power, ground, tach signal, and illumination.

[delinquent]

i just seen a factory tach go for well over 300 on ebay.

[spencermumma]

I paid 40 for mine in excellent shape just need a way to hook it up now

[Mark Nixon]

Which plug connector does it have?
The flat one, or the one that's odd-shaped?

The flat one is for 1992-'93, the odd-shaped one fits the 1990-91 trucks.

If you dig around under the dash, closer to the e-brake pedal, there is an accessory connector for the tach, which MAY already be in use for some other item (I forget what).
NORMALLY the early tach package ('90-'91) comes with a more elaborate harness than the later ('92-'93) set-up, but it is designed with an extra plug so whatever else is used there can still be wired in.

As far as a crank sensor, all you need it generic 2-wire sensor to read off the 2 notches on the damper.
Don't quote me on this, but you MAY be able to make the 1992-'93 crank sensor work, all you need is to figure out which 2 wires are the ones that generate the pulse and leave the 3rd one vacant.
I have several of the 1992-up sensors and mounting hardware.

The damper on a 1990 SHOULD have the notches, some do, some don't, but adding them isn't too hard, they are just 180* apart on the outer ring.

Somewhere on here BobS has pics (or a link) of the early tach and harness set-up.

FOUND THE LINK:
viewtopic.php?f=30&t=9861&p=72603&hilit=Tach#p72603

Mark.

[spencermumma]

I pulled it off of a intercooled truck but what if I were to.put a super dampener and got a sensor pickup would it work?