I got a 1990 cummins and i was wanting to put a tach on it, but not sure how. Ive heard there is ones that will plug right in, but not sure where to get them. Any help?

 

look here

https://www.dieselbombers.com/1st-ge...ach-gauge.html


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Dont think your truck has the plug in not till 91.5 . You can use any air core type tack and a picup from ISSPRO all you gotta do is glue two tiny magnets on your dampner at 180° apart . do a search on e-bay i found a nice retro isspro 3" tach for $25.00. If your wondering what an air core tach is its a pickup style tack that will have DIP switches in it to select the number of cyl .

 

I just acquired a "Dodge" (dealer Installed) tach from a 1991 Non-intercooled truck, which also works with the '89 and '90 trucks, as well as the '91 Intercooled.
They were available as a dealer install (as the '92-'93 style was) and have a very unique wiring and sensor that reads off the crank balancer.

The tach itself looks and wires up the same as the '92-'93 tach does, it just has this very elaborate wiring harness.

I'll get pictures of the tach, sensor and the wiring up sometime in the next day or 2.

Mark.