Tachometer...??

[89dudney]

Does anyone on here have a thread on how to wire a tach into a truck that doesnt have the wiring for one. I have a 90 and it does not have the wiring harness to plug a factory tach into so Im thinkin i may just buy and autometer tach from oriellys. I noticed they have one that only goes to 4 grand....should be all i need for a while.....

[ellis93]

Autometer makes a diesel tach that uses a pickup that straps the alternators case. It works like a champ and mines been on for 7 or 8yrs now. I think their about 150$ now,probably the best bang for you buck.

[CumminsPower59]

I've ran an Autometer a while back, I run an Isspro right now. I used the signal kit to run it on my 91. They are both nice units.

[89dudney]

http://www.carid.com/universal-custom-g ... MgodpTkAMg

Is this the one? It even matches my boost/pyro.

[ellis93]

Yep

[njettman]

Can I still use the factory tach wiring on my 92 if my pcm voltage regulator is bad and i did the external swap?

[CumminsPower59]

I don't know on that, but you can still try and let us know how it goes

[KB-Cummins]

Can I still use the factory tach wiring on my 92 if my pcm voltage regulator is bad and i did the external swap?

If the tach signal comes from the PCM then you may be SOL with the factory harness. That being said, if the signal is hard wired to the alternator then you might get lucky. A good wiring diagram would tell you. I've tried to look one up but I haven't had any luck finding a good enough diagram to show the tach wiring.

[njettman]

damn im having the same problem finding a diagram. I may just end up buying the kit for the alt. I already have a tach. thanks

[captjackm]

damn im having the same problem finding a diagram. I may just end up buying the kit for the alt. I already have a tach. thanks

I have been studying the manuals for my 1993 W250 5.9L 6cyl. According to the manual for my year there is a tach connector under the steering column. As I understand the wiring, inputs and outputs, I believe that the factory tach gets its signal from the crankshaft position sensor.

I can't tell you if the wiring is the same for the 1992 though.