Voltage limiter, fuel & temp gauges, '66 Sport Fury

[Labradorian]

The multi-plug going to my gauges has four wires. They are 12V supply (for temp/fuel limiter), temp sender, fuel sender, and instrument lamp power. As you suggested Grimley, I pulled the 12V bullet connector out of the plug and used it to power the electronic regulator. I'm now running a variable regulator that is adjusted to maybe 5.2 volts and my temp and fuel gauges are working nicely. I did replace my fuel gauge because the original one to the car had burned out and my repair was less than stellar. I happened to come across a set of gauges that were in good condition.


I have given up on the built in voltage limiter also........and i just saw your post. I have a couple of questions. i have a 66 monaco with fury gauges(canadian monaco)

if you don't mind me asking, what did you use as a regulator? did you build it?

Im not sure if my gauges are fried or not. How does one know if the gauges are fried. resistance check? I do have spare temp gauges and fuel gauges but the voltage limiters are bad in them all.

thanks

Glen

 

[mcmlvii]

Hi Glen. Great car you have.

if you don't mind me asking, what did you use as a regulator? did you build it?

Im not sure if my gauges are fried or not. How does one know if the gauges are fried. resistance check? I do have spare temp gauges and fuel gauges but the voltage limiters are bad in them all.

thanks

Glen

I made a voltage regulator using an LM317 chip, fixed resistor, small pot, a couple capacitors, and a heat sink (the chip gets quite warm when "running"). Here's a photo of it:

You can search the net for a schematic of these things. I'd originally built a fixed 5v regulator but it didn't drive the gauges high enough. As I recall, it didn't put out quite 5 volts though. My newer regulator is running about 5.2 volts and the two gauges are registering great.

To check if your gauges work, you can use a 5v DC power source (I initially had used a computer power supply, others say a cell phone charger works) and hook the gauges to the source. You should see movement almost immediately after applying power. Don't leave the voltage connected to the gauge for too long though. The gauges are meant to show a full scale reading with a small resistance in the line. You could also use an ohmmeter to do a quick check if your gauges read open (meaning a broken wire internally).

 

[Labradorian]

Hi Glen. Great car you have.



I made a voltage regulator using an LM317 chip, fixed resistor, small pot, a couple capacitors, and a heat sink (the chip gets quite warm when "running"). Here's a photo of it:

You can search the net for a schematic of these things. I'd originally built a fixed 5v regulator but it didn't drive the gauges high enough. As I recall, it didn't put out quite 5 volts though. My newer regulator is running about 5.2 volts and the two gauges are registering great.

To check if your gauges work, you can use a 5v DC power source (I initially had used a computer power supply, others say a cell phone charger works) and hook the gauges to the source. You should see movement almost immediately after applying power. Don't leave the voltage connected to the gauge for too long though. The gauges are meant to show a full scale reading with a small resistance in the line. You could also use an ohmmeter to do a quick check if your gauges read open (meaning a broken wire internally).

Thanks, my parents bought this monaco new.

Did your original regulator that you built have the 7805 chip? I was going to go that route but sounds like not the best idea. I will look for the schematic for the LM317 the one you built. I Like the ability to adjust the output voltage as need be. I can order all the parts from Digikey.ca

thanks again

glen

 

[mcmlvii]

Yes, it was a 7805 I originally used.

 

[commando1]

Yes, it was a 7805 I originally used.

I think I wiped out Radio Shack burning through 7805s. I went back and bought a NOS VR for an obscene (to me) amt. and it has worked without a hiccup.

Just my personal experience.
Your mileage may vary.

 

[Labradorian]

I think I wiped out Radio Shack burning through 7805s. I went back and bought a NOS VR for an obscene (to me) amt. and it has worked without a hiccup.

Just my personal experience.
Your mileage may vary.

Is this NOS thing something newer that is solid state? or is it one the older voltage regulators?

thanks

Glen

 

[Labradorian]

Yes, it was a 7805 I originally used.

Hi John

Did you put your circuit board in a small box or anything or just leave it all open as shown.

Is the POT 1000ohm?

cheers

Glen

 

[mcmlvii]

I don't remember what I used for the pot but I think the variable resistor is about 10 times the resistance of the fixed resistor, so if you're using something in the neighborhood of 100-120 ohms for the fixed resistor, the variable resistor would be around 1000. I did find a scrap of paper that showed .1 microfarad for the V-in cap and 10 microfarad for the V-out cap. I thought I had the other information documented but unfortunately I don't. I just left the board open behind my gauges when it was done.

 

[Labradorian]

I don't remember what I used for the pot but I think the variable resistor is about 10 times the resistance of the fixed resistor, so if you're using something in the neighborhood of 100-120 ohms for the fixed resistor, the variable resistor would be around 1000. I did find a scrap of paper that showed .1 microfarad for the V-in cap and 10 microfarad for the V-out cap. I thought I had the other information documented but unfortunately I don't. I just left the board open behind my gauges when it was done.

thanks

I found this link, pretty much what you did. click here

 

[saylor]

commando we are talking about using a PC power supply as a bench voltage source for testing.

it plugs into AC on one end already, and you could hack off the mc4 connectors or whatever they are and have 5 and 12 volt wires available - put alligator clips on, or hook to a buss bar, or whatnot.

you maybe already figured out that's what we meant...

but there you have it.



- saylor

 

[commando1]

Is this NOS thing something newer that is solid state? or is it one the older voltage regulators?

thanks

Glen

Just an older original one in the box. Paid dearly but it worked and is still working.
I refuse to tear apart the dash one more time.

 

[commando1]

The VR doesn't deliver a constant 5V.
That is not how that VR works.
It delivers between O and 12V in cycles for an average of 5V.

 

[Labradorian]

after doing some research i ended up ordering a VRC601 voltage regulator. $45 to my door here in canada from amazon.com

I found a 5V computer power supply to bench test the gauges and the temp gauge was fried, out of the three gauge clusters i have, i managed to find a good temp and fuel gauge. the voltage limiter in all 3 fuel gauges were bad but only 1 good gauge.

the fuel sender circuit in the car measure about 40ohms. the temp sender signal is measuring (Cold) about 400ohms but I benched tested the sender with a heat gun and it works.
I know the fuel sender is not working properly, either stuck or what not. i don't plan on hooking up the new regulator untill i replace the fuel sender.

cheers

 

[commando1]

I always appreciate those that will sit down and will diagnose a problem. The knowledge you gain is invaluable down the road.

 

[Labradorian]

I always appreciate those that will sit down and will diagnose a problem. The knowledge you gain is invaluable down the road.

i can't imagine what people did before the internet if you lived in a small remote area and needed parts for very old vehicles or needed to talk to other people in the industry. these forums are priceless.

 

[mcmlvii]

Glad you found a regulator.

the fuel sender circuit in the car measure about 40ohms.

For info, the fuel sender should read somewhere around 73 ohms empty and 10 ohms full (from what the all-knowing interweb says).

 

[Labradorian]

Glad you found a regulator.



For info, the fuel sender should read somewhere around 73 ohms empty and 10 ohms full (from what the all-knowing interweb says).

Thanks for the info. And this is what my new sender reads. The funny thing is that i have another spare fuel sender my father had given me as part of the spare parts pile but it reads the opposite? 75ohms full and about 10 empty. I was using it when i was bench testing and i first thought the fuel gauge was f#$ked. As i raised the lever to simulate a full tank the guage would go down and vice versa. So i tried the new sender and the gauge works fine.

Thanks again

 

[C-440-300]

I wanted to add my recent 2.5 cents on this. '66 Chrysler fuel gauge inside the column console. I used this circuit from Vintage Chrysler (Allpar.com)
Vintage Chrysler electrical repairs and updates (part 2)
and on a full tank, got above 3/4 full reading.
Then I saw this review:
Efficient DC 12V to 5V conversion for low-power electronics, evaluation of six modules | Arik Yavilevich's blog
and bought this
https://www.amazon.com/gp/product/B00XPZ7I4I/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1

If those links don't work, let me know.
Now I get a smidgen over the Full mark for a full tank.
The main issue with the ALLPAR and similar 7805s/equiv is the current draw. It's over 1 Amp. This unit handles 3A, more than enough and with enough margin. Plus, there is no need for heatsink and it draws so little power - way more efficient.