Swapping the Large fuel Gauge with a Tach!!! Smaller fuel gauge!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BorregoK5, Jan 14, 2002.

  1. BorregoK5

    BorregoK5 1/2 ton status

    Sep 7, 2001
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    San Marcos, Ca USA
    I hate having a large fuel gauge next to my speed-o where the tack should be. I'm going to try and swap a small fuel gauge (full to empty = 0 to 90 ohms right) into an empty slot next to my oil pressure and drop an aftermarket tach in its previous place. Has anyone done this or have any suggestions to a good swap in tach? I'm kinda bummed too, I've always purchaced aftermarket tach's with Rev limmiters built in but now I can't find one to save my life ( I have redline restraint but the wife loves to leadfoot!), anyone know where I can find one?

    I started with nothing and I still have most of that left! - <a target="_blank" href=> Pictures</a>
  2. K5 NUTT

    K5 NUTT 1/2 ton status

    Feb 17, 2000
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    Grand Junction Colorado
    Bottom left under Volt gauge...optional gauge hole used for clock option...if no clock you can install the small w/tach fuel gauge in that position...the wiring diagram shows the sending unit wire going to both locals...plus i did it to my 79 and it worked...

    I just plugged in a tach cluster and no problemo...i realize you have no tach cluster....but i think things will work out just fine...no clue on the ohm scale ? ....never went that far...good trivia question though...tomorrow i'll take ohm readings on my new to me via ebay 87 up sender in the full and empty positions and post back.


    1979 K5 350 TBI
    1976 K5 Chalet
    If it ain't got arizona pinstriping.....you ain't wheelin the pee outa her!
  3. Blue85

    Blue85 Troll Premium Member

    Jul 26, 2000
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    Grand Rapids area
    I did this. (no pictures). I had some extra gauges floating around, so I used a stock battery or oil pressure gauge (can't remember which one) and drilled out the little rivets that hold the drive unit to the face. The drive unit for the fuel gauge is the same size, so I attached the fuel gauge to this gauge face and mounted it in the empty "clock" slot. Then I rerouted the wiring for it over that way. The backlighting naturally works just like for all the other gauges.

    For the tack, I used this old 2 1/4" tach that I had sitting in the clock slot for a while (but of course this was all wrong...). I took all of the guts and attached them to the big fuel gauge face. Attaching the needle was hard because the factory needles stick on to the front but this tach has the needle coming out from the gauge motor between it's two end bearings. I bent the old needle part up and around like a "U" to get around that end bearing and then soldered one of the factory needle attachment points to it. This let me run the big fuel gauge needle on the tach, so it matches the speedometer. The drawback is that this needle has a lot more mass than the one that came on it, so the tach overshoots on quick rpm changes.

    I drew the gauge faces on a computer using the original tach and fuel faces to get the angles from. I modeled the tach face after pictures I had seen of the factory chevy truck tach, but mine is like an 8000rpm tach, so the scale is a lot different. I considered setting the tach to 6 cylinder mode and making it a 6000rpm scale, but I never got around to testing to see if it would work. But it would have been cool to use all 300 degrees of movement, or whatever it is. The fuel gauge is a little more than 90 degrees from full to empty. I printed them out on a color laser printer on transparency film so that the surface was smooth and shiny like the factory gauges. Since printers can't print white, I put white-out on the back of the transparency after printing everywhere there were white numbers or tick marks. Then I just glued them on to the old gauge faces. You have to look at it pretty carefully in the right light to see that it's not original.

    Over all, I'm very happy with it, especially since I didn't spend any money on it. I am planning to redo the fuel gauge someday, because I am getting about 100 degrees of movement on my 90 degree scale. I may also go back and set the tach to 6 cylinder mode and make a new face for it because talking about it makes it seem pretty cool now. I can send you the files for my gauge faces if you would like them.

    <font color=green>Today's Forecast: Partly cloudy with a chance of mud</font color=green>
  4. dyeager535

    dyeager535 1 ton status Premium Member

    Dec 13, 2000
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    Roy WA

    BTW, found the donor of those gauges (dad picked up the originals, didn't take note) in the wrecking yard yesterday for the tach/fuel gauge, 1978 Camaro. Colors and type face aren't QUITE right, but close. My fault for using the wrong color needle on the tach. Make sure its an 8 cylinder donor : )

    Blue85's procedure is right on for getting it to work.

    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?

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