Temp and Gas Gauge Questions

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wayneyada
Posts: 2
Joined: Mon Jan 07, 2019 12:53 am

Temp and Gas Gauge Questions

Post by wayneyada » Mon Jan 07, 2019 1:03 am

Hello to all. I am new to the forum and am in the process of finishing up a minor restoration of a '57 baby bird for a friend.

Both temp and gas gauges peg to Hot and Full when ignition is turned on. Engine is not hot nor is tank full. Thinking possibly a ground problem. Any thoughts?

Another question: I saw that vendors are selling temp sensor removing tools. Why is that needed? Looks like a deep socket or good box wrench should work.

Thanks much!

Wayne

apines
Posts: 56
Joined: Wed Jun 01, 2011 2:05 pm

Re: Temp and Gas Gauge Questions

Post by apines » Mon Jan 07, 2019 10:51 am

I would suspect the voltage regulator (AKA "constant voltage unit"). I'm not sure where it's physically located on a '57 but if you look at the wiring diagram you can see it between the ignition switch and the fuel and temperature gauges (not much daylight between those things so it's probably right up there under the dash). From the drawing it looks like it has a black/green wire on both sides, which seems odd. You should see 12V on the input side (toward the ignition switch) and 6V on the output side (toward the gauges).

-Andrew
current:
1955 Ford Thunderbird
1966 Ford Thunderbird Q-code convertible with Highway Pilot
past:
1974 Triumph TR6
1968 Ford Galaxie convertible
1974 VW Super Beetle
1981 Checker Marathon

apines
Posts: 56
Joined: Wed Jun 01, 2011 2:05 pm

Re: Temp and Gas Gauge Questions

Post by apines » Mon Jan 07, 2019 11:01 am

One more thing -- if the regulator isn't properly grounded it might just pass the voltage and not regulate. So, I'd agree with you that it might be a ground issue and that you should first check that the regulator is properly screwed into the body so it grounds well.

To be clear I'm talking about the instrument regulator (part #10804 at all the supply houses), not the regulator on the generator.

-Andrew
current:
1955 Ford Thunderbird
1966 Ford Thunderbird Q-code convertible with Highway Pilot
past:
1974 Triumph TR6
1968 Ford Galaxie convertible
1974 VW Super Beetle
1981 Checker Marathon

fordrodsteven
Posts: 149
Joined: Mon Apr 24, 2017 7:46 pm

Re: Temp and Gas Gauge Questions

Post by fordrodsteven » Mon Jan 07, 2019 12:34 pm

On my '55 the constant voltage regulator was mounted (clipped) onto a body lip (up under the dash) that goes all the way across the car. I had two of them for some reason (one for fuel gauge and one for temperature gauge) but a lot of sources say you only need one for the two gauges (as does this diagram). Here is a copy of the wiring diagram from one of my very old Parts Digest books.
gauge circuit.jpg
Steve - 1955 Thunderbird

Hazard 56 T Bird
Posts: 112
Joined: Thu Mar 02, 2017 1:40 pm
Location: Southeast Kentucky

Re: Temp and Gas Gauge Questions

Post by Hazard 56 T Bird » Mon Jan 07, 2019 8:58 pm

Another question: I saw that vendors are selling temp sensor removing tools. Why is that needed? Looks like a deep socket or good box wrench should work.
To remove the inside threaded bushing which holds the temp sender and which is pressed into the head.

tnswt12
Posts: 100
Joined: Sun Jan 07, 2018 11:31 am

Re: Temp and Gas Gauge Questions

Post by tnswt12 » Wed Jan 09, 2019 11:17 pm

I recently replaced the instrument voltage regulator (ivr) on my 57 TBird. Space is limited in that area behind the dash. Thin hands and arms certainly are an asset.

First, if you purchase NOS be certain the ivr is for the TBird and not for the passenger car. Most sellers on the popular auction site erroneously don't differentiate between the two.

Removing the ivr can be accomplished by working on your back and from under the driver's side of the dash.

Second, disconnect the power at the battery. Give yourself more room to work by disconnecting the cable to the tachometer and speedometer. I found it easer to see the ivr mounting nuts by positioning my head to the left of the steering column (left as viewing the column from under the dash). Make a note of how the 2 wires are attached before disconnecting them. The best tool I found for the job is a short handle nut driver with the appropriate size socket (at the present, I forget the size of the socket). Once you have sighted the nuts that hold the ivr in place go in from the right side of the steering column to remove them, you have more room.

Installing the new ivr will be challenging because mounting the nuts on the mounting studs is difficult and you will likely fail several times before you succeed. I found that using a small amount of caulk, paper or tape to hold the nut in the socket helps and prevents the nut from falling out of the socket as you move toward the mounting studs.

Replace the wiring.

When it comes time to reconnect the battery, brush the battery terminals first to ensure you have no electrical issue, otherwise, you risk burning wires.

Allow sufficient time and don't rush. Rest your hands when they tire, then move forward again. It's all doable!

Hazard 56 T Bird
Posts: 112
Joined: Thu Mar 02, 2017 1:40 pm
Location: Southeast Kentucky

Re: Temp and Gas Gauge Questions

Post by Hazard 56 T Bird » Sat Jan 12, 2019 7:21 pm

Interestingly (or maybe not) the 56 does not have the IVR or CVR!

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55Greg&Amy
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Joined: Sun Nov 09, 2008 8:43 am

Re: Temp and Gas Gauge Questions

Post by 55Greg&Amy » Sat Jan 12, 2019 9:40 pm

If I remember correctly, the 55’s used 6 volt gaugess on a 6 volt system and the 56 used 12 volt gauges on a 12 volt system so no IVR or CVR was needed. In 57 they went back to a 6 volt gauge on a 12 volt system so they installed a CVR to reduce the voltage to 6 volts to the gauges.
Greg Minnich
Fort Wayne, In

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paul2748
Posts: 1176
Joined: Sun Mar 15, 2009 12:23 am
Location: Northeastern New Jersey

Re: Temp and Gas Gauge Questions

Post by paul2748 » Sat Jan 12, 2019 10:38 pm

Correct
55Greg&Amy wrote:
Sat Jan 12, 2019 9:40 pm
If I remember correctly, the 55’s used 6 volt gaugess on a 6 volt system and the 56 used 12 volt gauges on a 12 volt system so no IVR or CVR was needed. In 57 they went back to a 6 volt gauge on a 12 volt system so they installed a CVR to reduce the voltage to 6 volts to the gauges.
1956 Fiesta Red 312
1954 Ford Victoria 312
1948 Ford Convertible Street Rod 302

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