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Username Post: 12 volt System / 6 Volt Fuel Gauge        (Topic#368469)
RAM_51 
"6th Year" Silver Supporting Member
Posts: 6277
RAM_51
Loc: Yakima, WA. USA
Reg: 12-28-02
05-20-22 02:49 PM - Post#2841544    

Forgive me, I'm taking about a '53 6500 truck (out of correct forum), but I don't see why a car would be any different.

Particulars:
•Previous owner converted to 12 volt system and gas gauge never worked.
•I replaced the tank sending unit with an NOS 6 volt unit as the one in the tank was toast.
• I replace the gauge with a new 6 volt unit with a voltage reducer, but may have hooked it up backward but only briefly....the red tag confused me.
• In any event, the gauge still does not work

For simplicity sake, let's say I have a 12 volt system and a 6 volt sending unit and nothing else at this point as I may have fried the 6 volt gauge. What would I need to do, what would I need to buy, what would I need to switch out to get "the" gauge / "a" gauge (6 or 12 volt) working?

I'd like to keep the original cluster and not have to hang another gauge from the bottom of the dash.


1951 Fleetline Preservation
'51 Fleetline DeLuxe 2 DOOR SEDAN (Fathom Green)
'51 Styleline Special BUSINESS COUPE (Shadow Gray)
'53 6500 Dump Bed (Oxidized Red)
'50 Styleline DeLuxe 4 DOOR SEDAN (Mist Green)


 


Keith_Knox 
Member #189 Moderator and "20th Year" Platinum Supporting Member
Posts: 6898
Keith_Knox
Age: 80
Loc: Napa, Ca USA
Reg: 04-02-00
05-20-22 05:36 PM - Post#2841547    
    In response to RAM_51

Here is Bob Hayden's conversion on his 54. Shows the gas gage reducer. I don't know where the reducer should be placed.
Also have heard it called a Runtz reducer.

29-41, 42-48, 49-54 Moderator
1948 Chevy Fleetmaster Coupe Purchased 6/2010. Stock with rebuilt 52 216 installed May 1966.
1965 Chevy II 2 door post 350 3 speed manual
2019 Ford Ranger Lariat Super Crewcab


 
RAM_51 
"6th Year" Silver Supporting Member
Posts: 6277
RAM_51
Loc: Yakima, WA. USA
Reg: 12-28-02
05-20-22 05:58 PM - Post#2841549    
    In response to Keith_Knox

Thanks Keith. I didn't see a link, but I assume this is what you are referring to?

15. Install Fuel Gauge Reducer. If you bought one from NCA, it has real nice instructions and parts, else, its pretty easy. Connect the 2 pink wires with a fuse on the end to one side of the reducer, connect the other side of the reducer to the terminal on the gauge of which the fuse came off using a 3/8" wrench.

1951 Fleetline Preservation
'51 Fleetline DeLuxe 2 DOOR SEDAN (Fathom Green)
'51 Styleline Special BUSINESS COUPE (Shadow Gray)
'53 6500 Dump Bed (Oxidized Red)
'50 Styleline DeLuxe 4 DOOR SEDAN (Mist Green)


 
Dave in VA 
Silver Supporting Member
Posts: 501
Dave in VA
Age: 71
Loc: SW Virginia, USA
Reg: 03-11-18
05-21-22 06:13 AM - Post#2841564    
    In response to RAM_51

My car has been converted to 12v. My gas gauge works properly, but it bounces around while driving. I don't see anything hooked to the gauge. Could my 6v gauge be working on 12v?

"Knowledge is Good" -- Emil Faber

U S Navy MM2 1970-75 USS Canisteo AO-99, USS Miller DE-1091 (The Champagne of Ships)

1950 Styleline Deluxe 2dr, mostly stock, driver quality...new to me 3/18
2017 Silverado LTZ 6.2
2020 Blazer Premier



 
pauldian 
Contributor
Posts: 474
pauldian
Loc: seligman,arizona
Reg: 05-14-09
05-21-22 06:49 AM - Post#2841567    
    In response to Dave in VA

You'll need a 12 to 6 volt reducer on the power wire to the gauge to eliminate the bouncing .

Remember,I'm not always right. But I'M never WRONG !


 
rrausch 
"17th Year" Silver Supporting Member
Posts: 14833
rrausch
Loc: L.A, Cal. & St. Louis...
Reg: 04-07-03
05-21-22 07:37 AM - Post#2841569    
    In response to pauldian

If you fried the gauge, you'll know by the burnt windings on one side of the back of the gauge, also by the smell. The Runtz resistor is the way to go. Back in the 1980's, when I was restoring my first '54 Chevy pickup, those Runtz resistors were mysterious and expensive. Over the years they've gotten very affordable.

1953 210 Convertible, 261 with dual Carter YF 966S carbs, P.S., Remote Bendix P.B. Booster... shade-tree restoration about done.




 
RAM_51 
"6th Year" Silver Supporting Member
Posts: 6277
RAM_51
Loc: Yakima, WA. USA
Reg: 12-28-02
05-21-22 08:43 AM - Post#2841571    
    In response to rrausch

It has been awhile since I worked on it. I assumed the gauge I took out was burned up as the windings on either side were black. When I briefly mis-wired the new gauge I did not smell anything and the windings are still bright, but I think I'm gonna start from scratch with a different gauge regardless. I was using the Runtz reducer, but even with the gauge wired correctly I got no movement from the needle. It sits at about 1/4 tank and does not deviate. I remember making sure all connections were "bright and tight". Hum...I now see two reducers suggested. I'm obviously going to have to lay everything out on the bench and fiddle with things until I can get the gauge to work there first. The last photo is the Frankenstein Mess that the previous owner[s] created and that I'm currently reverse engineering

Attachment: NCA_12v_to_6v_Fuel_Gauge_Reducer.jpg (322.47 KB) 10 View(s)




Attachment: Runtz_12v_to_6v_Reducer.jpg (68.61 KB) 5 View(s)




Attachment: 1953_6500_Wiring_.jpeg (3.47 MB) 3 View(s)




1951 Fleetline Preservation
'51 Fleetline DeLuxe 2 DOOR SEDAN (Fathom Green)
'51 Styleline Special BUSINESS COUPE (Shadow Gray)
'53 6500 Dump Bed (Oxidized Red)
'50 Styleline DeLuxe 4 DOOR SEDAN (Mist Green)


 
Lowliner 
Newbie
Posts: 14

Loc: Michigan
Reg: 04-23-14
05-21-22 07:11 PM - Post#2841587    
    In response to RAM_51

I went through a similar exercise with my gas gauge when I converted to 12 volt. My issue was an open in the wire from the tank sending unit to the gauge.



 
rrausch 
"17th Year" Silver Supporting Member
Posts: 14833
rrausch
Loc: L.A, Cal. & St. Louis...
Reg: 04-07-03
05-22-22 05:41 AM - Post#2841604    
    In response to Lowliner

You might try running a new wire from the sending unit to the gauge. When I did my conversions I only used one Runtz.

1953 210 Convertible, 261 with dual Carter YF 966S carbs, P.S., Remote Bendix P.B. Booster... shade-tree restoration about done.




 
RAM_51 
"6th Year" Silver Supporting Member
Posts: 6277
RAM_51
Loc: Yakima, WA. USA
Reg: 12-28-02
05-22-22 08:22 AM - Post#2841611    
    In response to rrausch

  • rrausch Said:
You might try running a new wire from the sending unit to the gauge.


I did that and had the gauge on the seat cushion with a short wire directly from the sending unit and a hot wire directly from the battery. I'm setting things up again in the shop on the bench and being very deliberate to include the piece of cardboard between the terminals and all the correct washers etc. We'll see.

UPDATE:
Some progress. I decided to start at a baseline using 6 volts and also using a couple of fuel gauges that I have sitting around.

The first gauge I tested up was a re-decaled GMC gauge. It only seemed to give me half values with a reading just beginning to come off of "E" with the float half way up and only a "half tank" reading with the float all the way at the extreme up position. That seemed odd...I thought maybe the NOS sending unit I installed and the one you see here is/was a 12 volt unit. I have the box with the AC part number on it somewhere. It would probably take a day to find and maybe as long to research it.

I then decided to test an OEM Chevrolet gauge I recently acquired on eBay. It's a little difficult to see through the glass, but this gauge performed correctly or at least better than the GMC gauge and put to rest my concerns that the sending unit was incorrect. As I say...PROGRESS!


Attachment: Re-Decaled_GMC_Fuel_Gauge_with_6_Volt_Supply.jpg (1.54 MB) 16 View(s)




Attachment: OEM_Chevrolet_Fuel_Gauge_with_6_Volt_Supply.jpg (1.58 MB) 10 View(s)




1951 Fleetline Preservation
'51 Fleetline DeLuxe 2 DOOR SEDAN (Fathom Green)
'51 Styleline Special BUSINESS COUPE (Shadow Gray)
'53 6500 Dump Bed (Oxidized Red)
'50 Styleline DeLuxe 4 DOOR SEDAN (Mist Green)


 
Dean50 
"16th Year" Gold Supporting Member
Posts: 1823
Dean50
Loc: Detroit area
Reg: 01-02-07
05-22-22 02:58 PM - Post#2841636    
    In response to RAM_51

Sounds like you're getting close, Ram. I installed a new tank and sender a couple of years ago and found out last summer while cruising on the freeway that the tank is actually empty one dot before the gauge reads empty. I coasted up the next offramp, made the green light at the top of the ramp and coasted into a gas station. A little excitement in the old Chevy!

Dean50



 
tommy49 
"8th Year" Silver Supporting Member
Posts: 3301
tommy49
Loc: Kaleva, Michigan
Reg: 09-28-12
05-23-22 07:15 AM - Post#2841665    
    In response to RAM_51

I've used this to test the gauge, a carpenter's pencil. Hook it up to the sender wires. My gauge showed 3/8 tank with the 7 ohm pencil.





Attachment: Fuel_gauge_tester.JPG (52.56 KB) 2 View(s)

Tommy

49 Deluxe Sport Coupe, 4.8/4L60E, MII IFS, Blazer rear axle, 4 wheel power disc brakes, power steering, air conditioning.

https://www.flickr.com/photos/tommyfortynine /album...




 
RAM_51 
"6th Year" Silver Supporting Member
Posts: 6277
RAM_51
Loc: Yakima, WA. USA
Reg: 12-28-02
05-24-22 08:00 PM - Post#2841761    
    In response to tommy49

I think I was sleeping in class when OHMS, WATTS, and AMPS were discussed, but I assume a difference in ohms may be the issue with the GMC gauge. I had to make up a few more jumper wires. I got that done, installed the RUNTZ - this one happens to say VINTIQUE on the back - and hooked it up to a 12 volt battery. I paid far greater attention to attaching the gauge to the cluster case this time. That may have been the issue with the gauge that is currently out in the truck. I will find that out eventually. In any event...SUCCESS! Confidence somewhat restored. Thanks for everyone's help and thanks for following along!

1951 Fleetline Preservation
'51 Fleetline DeLuxe 2 DOOR SEDAN (Fathom Green)
'51 Styleline Special BUSINESS COUPE (Shadow Gray)
'53 6500 Dump Bed (Oxidized Red)
'50 Styleline DeLuxe 4 DOOR SEDAN (Mist Green)


 
rrausch 
"17th Year" Silver Supporting Member
Posts: 14833
rrausch
Loc: L.A, Cal. & St. Louis...
Reg: 04-07-03
05-25-22 05:16 AM - Post#2841790    
    In response to RAM_51

Success! There's nothing like that feeling when the stubborn problem finally gets fixed.

1953 210 Convertible, 261 with dual Carter YF 966S carbs, P.S., Remote Bendix P.B. Booster... shade-tree restoration about done.




 
Dean50 
"16th Year" Gold Supporting Member
Posts: 1823
Dean50
Loc: Detroit area
Reg: 01-02-07
05-25-22 07:22 PM - Post#2841834    
    In response to RAM_51

Congrats, Ram!

Dean50



 


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