Gas gauge not working? I think I fixed it.

-
Just a thought... I have followed this thread, for the most part, but can't claim to have read and soaked in every single post.

Having recently been going through my own dash and electrical connections and finding almost all of the pins loose in the pc boards and re-soldering them, have you verified that you have perfect connections at all those points? In other words, there are no places for potential voltage drop-offs in the system? Sure is starting to sound like that may be an issue with the fluctuating readings.

To me, (if all the wiring and connections are solid) it should at least be consistent, even if it consistently wrong.
 
67Dart273 said:
Actually it does not take that much pressure. You would have to make some wood forms for the top and bottom or the thing will look like a rather boxy egg, LOL

If you try it in the car, don't forget to bend the pickup back into shape
Click to expand...

I should have said that you need volume not high pressure.
 
MobileCustoms said:
Just a thought... I have followed this thread, for the most part, but can't claim to have read and soaked in every single post.

Having recently been going through my own dash and electrical connections and finding almost all of the pins loose in the pc boards and re-soldering them, have you verified that you have perfect connections at all those points? In other words, there are no places for potential voltage drop-offs in the system? Sure is starting to sound like that may be an issue with the fluctuating readings.

To me, (if all the wiring and connections are solid) it should at least be consistent, even if it consistently wrong.
Click to expand...

My take on it is; the characteristics of the bi-metal coil inside the gauge has changed over the years. Due to years of heating and cooling and just plain age. If I was smart, I would buy a brand-new gauge and be done with it.
But then I would not have the challenge of fixing a problem. What fun would that be.
 
If and when I have spare time to work on the compressed air fix, I will probably try this. But there are 4 tubes to seal and two rather large openings that need to be sealed before I can apply the compressed air
 
Compressed air charge on a fuel tank can be extremely dangerous. If the tank was empty it would take some time to reach a dangerous p.s.i. but if the tank is nearly full you might pop it in a heatbeat. If I was going to try compressed air charge I would have to carefully monitor pressure applied while slowly charging probably just using the fuel senders outlet as a air inlet. At very low p.s.i. I would begin to tap around on the tank with a rubber mallet in effort to coax the bends.
 
thanks Redfish. I almost had it set up to go. I was going to video tape it in case it blew up and killed me, they would know for sure my cause of death was stupidity. I have now set it up so I can add the air from up to 100 feet away. It probably has an ounce or two of gas left in it that I could not get out.
Maybe I should fill it some with water, So if it explodes is will really look nice on video and will mean I need less air volume. I am getting ready to do this in the next 30 minutes, so stop me now if I am playing with death
 
If the tank is still installed there are several reliefs for X cubic feet of air.
Rubber hoses, seals, grommets, etc... Those wouldn't be safety devises by any ones standard but probably will mimic those actions.
 
This is my setup for pressurizing tanks. I start by turning the regulator to it's lowest setting, then open the valve on the left and slowly crank up the pressure on the regulator. the valve on the right is used for a little extra safety to bleed off pressure if need be. I go real slow and tap on the tank with a rubber mallet in the damaged area like Redfish said. You need a lot less pressure than you think and you can blow one up with unregulated shop air.
 

Attachments

  • p-test 003.jpg
    53.2 KB · Views: 282
I placed the tank outside and operated the air inside the garage.
I took a video and am attempting to upload it now. I have no idea if that will work.

Apparently I can not upload the file here. If you are interested you can watch it here. http://tinyurl.com/ms3sd2c

I cut the tank up after this. I needed a large piece of metal to fix something.
 
Just when I begin to think that I am finished, it pulls me back in.
I have the new spare tire well on order and have cut the steel for the other rust outs in the trunk, that was covered up with residential carpet cushion.
So I have torn out all the carpet and removing the cushions to find out what else was hidden.
There is rust under the drivers and passengers floor. Driver's side is the worst. Both sides the rust seemed moist, BUT NO rust-outs.

I will treat all spots that has surface rust and paint it. I will find some proper automotive carpet cushions and put them in. I will clean the carpet and then decide if I am going to trash it or reinstall it.

I bought a welder the other day and now have to learn how to use it.
 

Attachments

  • IMG_20140302_155235_652[1].jpg
    52.8 KB · Views: 245
  • IMG_20140302_155355_612[1].jpg
    49.3 KB · Views: 248
  • IMG_20140302_155314_422[1].jpg
    28 KB · Views: 223
  • IMG_20140228_172118_625[1].jpg
    126.1 KB · Views: 244
  • IMG_20140228_172045_290[1].jpg
    56.7 KB · Views: 252
Pawned said:
There is rust under the drivers and passengers floor. Driver's side is the worst. Both sides the rust seemed moist, BUT NO rust-outs.
Click to expand...
I was wrong, I sand blasted the floors for the driver and passenger. There were a bunch of pin hole holes. The worst two were about the size of a pencil lead. I will take me days to clean the inside of the car
 
Pawned said:
I will take me days to clean the inside of the car
Click to expand...
Ditto here. While I had everything out of the dash in my 64 Valiant, I decided to paint the whole underdash area. Some rust in the deep corners so I had to use my sandblaster. I need a proper dust-shield since sand fell in my eyes past my safety glasses and filled up my ears several times (fun blasting upward). Took 1/2 day to suck & blow the sand out of all crevices, even though I had covered everything w/ plastic. Someday I'll do a car like on TV - strip everything and send the shell to the media blasters and get it de-rusted and primed in bulk.
 
I needed a new gas tank, so put in the new one with the same sender that came out of the damaged tank. When it had approximately 12 gallons left, the gauge read a little above the full mark.
I put on the new tank and put 5 gallons of fuel in it and the gauge reads Empty.
I am not happy with the results of my fix on the fuel gauge.
I will continue to play with it and wait to hear about if Kitcarlson's fix works.

If I add one gallon at a time, I will see what I need to know

Ed
 
I sent the unit to Del, for some unbiased testing with an actual gauge. I moved a oin or two on the circuit, swapping a button pin for the LED. I did that do it would be easier to get fancy with LED intensity or other uses. I am not sure I posted the final schematic. I will check on my PC tomorrow.

I did buy some tiny45 chips and some button switches. Once we hear back from Del, if the news is good, I can send you a programmed chip, and switches for you to try.
 
I really appreciate it.
I am still hopeful I can get my fix ironed out. Although it does not look good. I have 5 gallons in there and it is reading EMPTY When I had about 13 gallons it was reading just above FULL. When the car finally gets put back together, I will try adding 1 gallon at a time to see how the gauge reacts.

I would also like to see your design in action
 
If you have an adjustable power supply 0-5V, apply directly it to the gauge meter. Start with low voltage. Find the voltage for empty, and full. I would think there needs to be a span of a half volt to have resolution. So for example empty is 3.5 and full is 4.0 the cal unit will work.

If you provide voltages and sender resistance values empty/full resistance values, I could hard code calibration. By doing that, circuit would be simpler to make. No buttons, and a few less parts. It will work only for your situation.
 
I used the sender from the damaged tank as the new sender had a 2nd port. I did do a side by side comparison and they had identical resistive measurements. Maybe there is somewhere the guts of gauge that can be transplanted into my housing.

I thought I had it and then again maybe I already do, time will tell
 
I found the holy grail. I was wrong before when I said that the meter could not be changed. Wrong again bucko..

Look at the picture of the inside of the meter. no much to it. Until I realized I could set the F where I wanted and same with the E.
It did take 6vdc to be able to get the meter to full.

I had it working on a test jig. It goes to full and empty at both ends of the sending unit. I think it will show some fuel levels between that, but I do not know yet.

So I put the cluster with the newly adjusted meter back in the car, only to find my voltage regulator from China is smoked. I bought 5 more so tomorrow I will put a new one in.


Do you see what I am referring to in the pix of the meter? Look and think. I will not leave you hanging. If I get it working 100% I will give a full explanation.

I just looked at the pix, not focused very well. but is still can be seen
 

Attachments

  • IMG_20140325_120712_674[1].jpg
    32.4 KB · Views: 172
nm9stheham said:
Haven't a clue....but I see some funky little tangs with holes behind them.....lol
Click to expand...


BINGO you put a tiny screwdriver into the holes in the back and move those "funky little tangs". That sets the limits on the meter. I put the sending unit to full and then move those "funky little tangs" to set the meter to F.
Then I put the sending unit to empty and then adjust the "funky little tangs" to the E.
I did have to increase the voltage to 6vdc to get the unit to travel to the F.

I needed to do this a bunch of times to get it set up the way I wanted it.
 
That is pretty cool to have figured out....after all the reports and ideas and work to calibrate these meters and sender. I would have seen them from the back and just thought "I wonder why they vented the gas guage?". Now the million $ question is how many/what years were these in the guages?
 
1967 'cuda said:
- been following this thread. good work!
Click to expand...


Thank you. I took the car out for a drive to test out the gas gauge running in the car in everyday use and NOT just on the test jig.

I does work beautifully. I am happier than a pig in poop.
Even though the meter is adjustable, it would not travel to the full stop without adding a little more voltage.
It was a coincident that the final voltage I needed is exactly what I was working with before. 6.03vdc

I did take a piece of 16 ga steel and cut a piece off appx 3/8" x 3/4" and drilled a hole in it. I then tapped it out to 6 x 32 treads. I soldered a piece of wire to it and connected the other end to the output of the Variable Voltage Regulator I am using.
I drilled a small hole in the cluster and then epoxied the 6 x32 hole over the hole in the cluster.
I am using that as a Test Point. Up until now I had to take the cluster out to adjust the voltage to a specific voltage. When I want to check the voltage on the Gas Gauge I put a screw into the hole and attach my volt meter to it.

Maybe I should copy this to a new thread, as this one is so long and confusing by the time you get to this page. I think I will so everyone can use this.
 
You must log in or register to reply here.
-

Back
Top