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General Category => Tech - Help Area => Body-Interior-Electrical => Topic started by: 454-3500-hd on May 26, 2011, 12:49:38 PM

Title: how do i install a rpm tachometer?
Post by: 454-3500-hd on May 26, 2011, 12:49:38 PM
I would like to install a tach on my 91 hd w/a 454 and auto trans, I don't want to put a big tach on the dash like a drag car just a small one so i watch my rpms. I beleave its called the colum,( between the windsheild and drivers door) I seen that lmc truck Carry's a 3 gauge piece of interior that mounts there. I was thinkin on installing a tach, tranny temp gauge , and something else (not sure yet any ideas are great). Thanks
Title: Re: how do i install a rpm tachometer?
Post by: someotherguy on May 26, 2011, 08:00:18 PM
Look at the harness at the ignition coil; you'll see a connector with a single wire, probably still folded back against the harness and taped to it.  White wire.  That's the tach signal.  Follow the other instructions for installing the tach (12V and ground, lamp) and connect the signal wire to the connector I mentioned.

You can "kind of" see it in this pic; connector is taped back to the flex-loom on the coil harness:

(http://www.someotherplace.com/bb/proj/rh94_int10s.jpg)

Richard
Title: Re: how do i install a rpm tachometer?
Post by: 454-3500-hd on May 26, 2011, 09:33:42 PM
Ok got it. Thanks again! Would a dash off of a 93c1500 with the tach swap on a 91 hd
Title: Re: how do i install a rpm tachometer?
Post by: someotherguy on May 26, 2011, 10:05:35 PM
No.  1988-1991 use a different style of dash cluster, and 1991 is even different from 1988-1990 by the placement of a few wires in the connector.  1992-1994 are very different electronically.  They can be retrofitted but take a pretty good amount of work.

Richard
Title: Re: how do i install a rpm tachometer?
Post by: ED-NY on May 27, 2011, 07:26:48 AM
Richard

See that you have one of those TBI fuel pressure tester adapters. They sell for about $30 on eBay..but you can buy them from Actron for about $6 each (and it's the same adapter).

I bought a few and passed them out to my Chevy motorhead friends.

Ed

Title: Re: how do i install a rpm tachometer?
Post by: someotherguy on May 27, 2011, 08:43:23 AM
Yep, I remember seeing someone post that they were on Actron's site ($6.84 to be exact) and also included with a couple of their fuel pressure test kits.  Of course, before that, I paid too much online for one... :D

Man; a lot of my example pics sure look like crap, especially the ones that were taken before I did my intake gaskets!

Richard