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

[mcmlvii]

As one of many Mopar owners plagued by the dreaded voltage limiter in use during the 60s, I decided to delve into getting my temp and fuel gauges working. I pulled the gauge set out of the dash and hooked 5 volts to the temp and fuel gauges. The temp gauge worked but the fuel gauge didn't. *sigh* So I drilled out a couple rivets in the fuel gauge face and removed it. What do I find but a hair-thin wire burned off, leaving two stumps. The circles highlight the broken wire. The blue arrow points to the offending voltage limiter integral to the fuel gauge.


(larger image here: https://lh3.googleusercontent.com/-...AL9s/yLkF7oDS_Dk/s1600/IMG_0093_annotated.jpg)

This is how I fixed the broken wire. I got some thin copper wire, wrap the ends around a needle, then slipped the coils over the two stubs of wire in the gauge. I crimped the coils onto the stubs, then put a dab of glue on for good measure. I did try to solder onto the stubs but the solder wouldn't stick to the resistance wire. I don't know how well my fix will last but at least for now it's working for the time being.


(larger image here: https://lh3.googleusercontent.com/-...AL98/GGZqKbBurMY/s1600/IMG_0094_annotated.jpg)
(...and here: https://lh3.googleusercontent.com/-...AL-M/c1hT7FSm_D0/s1600/IMG_0095_annotated.jpg)

I superglued the face back onto the gauge since I couldn't reuse the two small brass rivets previously drilled out.

(larger image here: https://lh5.googleusercontent.com/-...uI/AAAAAAAAL-g/BDFiZmc-T98/s1600/IMG_0097.JPG)

It was time-consuming but the gauges now work on the bench. My next step is to build one of those 5v power supplies that some folks on the net show how to do with a few basic parts from Radio Shack (or wherever), so I don't get bit by the dreaded Mopar voltage limiter again.


(larger image here: https://lh4.googleusercontent.com/-...vI/AAAAAAAAL_E/tD3UuSG5HXo/s1600/IMG_0102.JPG)

 

[bluefury361]

:sSig_greetingsthor: ......
There are improved performance voltage limiters avaliable. Mopar performance offers them.
Here is a link to one on ebay.....
http://www.ebay.com/itm/Mopar-Instr...ies&hash=item4acead9622&vxp=mtr#ht_1133wt_756

How about posting some pictures of your 66..... We like pictures.

 

[mcmlvii]

Thanks for the suggestion, 361. My limiter unfortunately is housed in the fuel gauge so is not a plug-in unit like the one on ebay. There's a site online though that shows how to make an inexpensive 5v power supply using a silicon chip, capacitor and heat sink. Should be pretty straightforward.

The only photos I currently have of the car are the ones I posted in my new member post a week or so ago, but hope to get more photos in the coming weeks.

 

[1978 NYB]

Good job! Please post all the innovative repairs that you do in the future. We love to see people overcome and adapt and repair everything.

 

[bluefury361]

The only photos I currently have of the car are the ones I posted in my new member post a week or so ago, but hope to get more photos in the coming weeks.
View attachment 23230 View attachment 23231 View attachment 23232

A 66 383 4speed .....!!!! I love it. Hard to get better then that.

 

[bluefury361]

Those inland shifters take a lot of guff ....... But I had a 66 383 4 speed Satellite with the inland shifter and never had a problem with it. Trust me .... It withstood several full power shifts. (once the reverse lock out cable broke but it was an easy fix.)

 

[commando1]

(once the reverse lock out cable broke but it was an easy fix.)

Hursts never break.

 

[mcmlvii]

I built a 5v regulator from parts purchased yesterday at Radio Shack for $6.49 after tax. The parts were: #7805 regulator, 10 microfarad-35v capacitor, and a heat sink. It puts out a steady 4.92v with a 12v input. Here's what the finished product looks like:

https://lh4.googleusercontent.com/-.../jM6bn1z5MaA/s800/IMG_20140110_182454_395.jpg

 

[commando1]

My next step is to build one of those 5v power supplies that some folks on the net show how to do with a few basic parts from Radio Shack (or wherever), so I don't get bit by the dreaded Mopar voltage limiter again.

I made a couple of those myself but it kept burning up the 7805 chips.
I bought one of these and it did the trick.

http://demonivr.com/

 

[mcmlvii]

I made a couple of those myself but it kept burning up the 7805 chips.

Well that doesn't sound too promising... I may have to go that route too. Thanks for the link.

 

[saylor]

get ya a PC power supply. any one. garage sale computer, used, throw away, anything you can find. the power supply has +5 and +12VDC out

 

[commando1]

Not getting the gist of your post, Saylor.

 

[mcmlvii]

get ya a PC power supply. any one. garage sale computer, used, throw away, anything you can find. the power supply has +5 and +12VDC out

I did use an old PC power supply to test the gauges before I spent the time making the voltage regulator. Thanks.

On another note, the temp and fuel gauges in the car still do not work..... hmmm. Well, let me rephrase that. They go full scale when I ground the sender leads to ground, but when I hook the leads to the senders, the gauges sit happily at nil, nada, zilch, zeronee bamboni. I put in a new temp sender and still nada. I even read the resistance of the fuel sender (25 ohms at the time, which should be somewhere around 1/2 tank) and the temp sender when the engine was warm, not hot (50 ohms as I recall), so the senders seem to be operating properly too.

My question to anyone out there is, do the gauges just get old and not operate properly when the correct resistance is being put out by the senders?

And Stan, I'm not ready to admit defeat on my 7805 regulator yet. It still puts out 5v. Thanks all.

 

[grimley]

I built a 5v regulator from parts purchased yesterday at Radio Shack for $6.49 after tax. The parts were: #7805 regulator, 10 microfarad-35v capacitor, and a heat sink. It puts out a steady 4.92v with a 12v input. Here's what the finished product looks like:
View attachment 23314
https://lh4.googleusercontent.com/-.../jM6bn1z5MaA/s800/IMG_20140110_182454_395.jpg

im looking to repeat this using an electronic regulator like you mentioned. How/what did you alter in your fuel gauge to disconnect/bypass the old regulator?

Once you repair your wire in the gauge, youd still have 12v (assuming faulty regulator) going to your gas/temp gauges, even if you connected up the 5v output from the electronic regulator. Im assuming you left the copper wire broken? did this keep the gas gauge regulator isolated from the rest of the circuit?

Would it be best to find which core in supplying 12v in the multi plug, cut it before the plug and have that 12v go straight to the electronic regulator and then have the 5v as ring terminal on A like you did??

 

[bulldogchesty]

Aren't most cell phone chargers 5 volts? Seems easier than finding an old computer.

 

[bulldogchesty]

http://www.moparmusclemagazine.com/.../23241_instrument_gauges_repair/photo_08.html

 

[68plymouth383]

I had a voltage limiter go out...... If you catch it fast enough, ie right when it happens shut the car off, and replace it. If you don't the gages get fried. There designed to run on 5 volts, the shorting to 12 volts Frys them quick..... at that point installing a good regulator/limiter won't fix them.

 

[grimley]

I had a voltage limiter go out...... If you catch it fast enough, ie right when it happens shut the car off, and replace it. If you don't the gages get fried. There designed to run on 5 volts, the shorting to 12 volts Frys them quick..... at that point installing a good regulator/limiter won't fix them.

I opened my fuel and temp gauges to find both of them burnt out. I've been able to repair them by removing some of the coil and soldering onto the terminal base. They work on a 5v power supply but I'm not sure what effect having less wraps of the coil has. Anyone got any answers?

At a guess, I'm assuming it will just take longer to give it's reading? There's the same amount of resistance in the circuit, just with removing some of the coiled wire it will induce less into the needle?

Or am I totally wrong? Haha.

Will be making up a electronic 5v reg today, fingers crossed

 

[mcmlvii]

How/what did you alter in your fuel gauge to disconnect/bypass the old regulator?
Would it be best to find which core in supplying 12v in the multi plug, cut it before the plug and have that 12v go straight to the electronic regulator and then have the 5v as ring terminal on A like you did??

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.

Aren't most cell phone chargers 5 volts? Seems easier than finding an old computer.

I have numerous computers in the attic that I haven't taken the time to dispose of, so I have more old computers than old cell phone chargers laying around.

 

[grimley]

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.

Thanks for the reply.

I ended up disconnecting the old mechanical regulator from the circuit (just cut the wire inside the the gauge leading from the terminal to the actual reg) and then picking up my 12v from that terminal outside the gauge using a ring lug to my electronic regulator. Havent had time to test in car but seems to work on bench setup at work (i dont work hard!) im more curious about how accurate this is alteration is going to be.

Ideally, id like to pick up a new temp gauge (who cares about fuel!) but finding it hard to find any!