gas gauge

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less frustrated
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gas gauge

Post by less frustrated »

Hello all,
I am trying to get my SRL to the point that I can drive it to Watkins Glen in September and be relatively assured I'll make it. I thought it might be wise to fix the gas gauge. It would only register up to 3/4 full. Whether it was accurate below that, I don't know but it did show usage below that. After doing everything I could think of, I ordered a new sending unit from Dean. I installed the new unit and it is registering slightly below full, but is not dropping as I drive as I expected. I have been driving locally with occasional drives at speed on the interstate hoping that anything wanting to break will break now, rather than 4 hours from home. Has anyone experienced something similar or can give me a hint of what may be wrong? Without advice, my next step will be to remove the sending unit and reinstall with a slightly different orientation.
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Re: gas gauge

Post by spl310 »

The fuel sending unit is nothing more than a potentiometer connected to a float. Reorienting it won't do anything unless you have it jammed. If you want to see if things are working, you can remove it from the tank, reconnect the wires, turn on the ignition and then operate it to see if it shows empty at full extention and full at least extention of the float arm.
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Re: gas gauge

Post by DAC21 »

Dash voltage regulator gone wonky? I just don't know if those regulators either work or they don't. Can they be somewhere in between giving readings but inaccurate? Good news is there are a couple cheap documented fixes.
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Re: gas gauge

Post by PF044 »

You might want to check the gauge itself by grounding the lead to the sending unit with the key on simulating a full tank. The gauge should sweep smoothly to full. With the ground removed the gauge should sweep smoothly from full to empty. If it fails this, the gauge is probably not working properly.
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Re: gas gauge

Post by DAC21 »

less frustrated wrote: Mon Jul 19, 2021 1:00 pm Hello all,
I am trying to get my SRL to the point that I can drive it to Watkins Glen in September and be relatively assured I'll make it. I thought it might be wise to fix the gas gauge. It would only register up to 3/4 full. Whether it was accurate below that, I don't know but it did show usage below that. After doing everything I could think of, I ordered a new sending unit from Dean. I installed the new unit and it is registering slightly below full, but is not dropping as I drive as I expected. I have been driving locally with occasional drives at speed on the interstate hoping that anything wanting to break will break now, rather than 4 hours from home. Has anyone experienced something similar or can give me a hint of what may be wrong? Without advice, my next step will be to remove the sending unit and reinstall with a slightly different orientation.
If your Water Temp. Gauge is also not working properly that would further point towards a faulty dash voltage regulator.
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Re: gas gauge

Post by less frustrated »

Thanks all. I replaced the regulator some time ago. Didn't affect the gauge. I figure the gauge itself is blown. I have a separate water temp gauge under the dash so I haven't fooled with the electrical sensor on the engine. I guess I'll remove the sending unit, pump out some gas, and reinstall after grounding to see if the range of the gauge works. Otherwise I guess I'll be keeping track of miles traveled to determine when to gas up.
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Re: gas gauge

Post by JT68 »

If the gauge is operating, it probably isn't "blown". My guess is either the sender is incorrect, or there is a poor connection somewhere.
The little regulator needs a good ground too.

You do know there are "empty" and "full" scale adjustments on the back of the gauge, yes? You turn them with a small flat blade screw driver.
Those adjustments are needed since the system isn't particularly precise.
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Re: gas gauge

Post by Gregs672000 »

JT68 wrote: Tue Jul 20, 2021 11:49 am You do know there are "empty" and "full" scale adjustments on the back of the gauge, yes? You turn them with a small flat blade screw driver.
Those adjustments are needed since the system isn't particularly precise.
I did NOT know that, so thanks.

My guage is similar and not something I rely on solely. I know I average about 20mpg around town and 25-26 hiway. The tank holds somewhere around 11.5 gallons as I recall, so I start looking for fuel at about 250 miles on a drive/trip. I always reset my trip meter with every fill up. In 35 years I've run out of gas once, while going up hill during a drive at Shasta. We had just enough momentum to carry us over the top of the final hill and the angle of the car changed enough to re-cover the fuel pick up in the tank, restart the motor and fly back to base. What's funny is my wife has it all on video and her Facebook reminds her of it every once in awhile.
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Re: gas gauge

Post by less frustrated »

I did not know about the adjustments. I wish I had known that when I had the seat removed so I could lie on my back whilst reinstalling the heater box and getting more and more nauseated. Fat and old age are not conducive to working under that dash. Thanks to everyone for their suggestions.
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Re: gas gauge

Post by Gregs672000 »

less frustrated wrote: Tue Jul 20, 2021 3:53 pm Fat and old age are not conducive to working under that dash. Thanks to everyone for their suggestions.
When I was 22 I had no problem laying anywhere I needed to in the car, including the trunk, twisting my body into impossible positions without a thought. Now, 35 years later, I groan at the thought of spending too much time under the dash, especially since I can't see crap unless my bifocal glasses line up just right, don't fall off and there's plenty of light. Later that night I'll find big bruises on my sides because I bruise more easily with my (now necessary) blood thinning meds, and a visit to the chiropractor the next day is likely if I want to walk straight the rest of the week.

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Re: gas gauge

Post by less frustrated »

I overlooked complaining about my trifocals. Before I retired, I invested in a pair of computer glasses that were bifocal. Works pretty well, but as you point out, that line.. As an old friend once told me, don't get old. But I haven't figured out an acceptable alternative. I don't want to waste the heart surgeon's time spent, nor the insurance's 100K for the quad bypass three years ago. I am living, and singing, the Paul Simon song 'old friends.'
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Re: gas gauge

Post by bossbob »

JT68 wrote: Tue Jul 20, 2021 11:49 am You do know there are "empty" and "full" scale adjustments on the back of the gauge, yes? You turn them with a small flat blade screw driver.
Those adjustments are needed since the system isn't particularly precise.
Can this adjustment be accessed without removing the gauge?
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Re: gas gauge

Post by rwmann »

The slots are on the back side of the combination gauge, at about the 8-o'clock and 7-o'clock positions looking at the gauge from the rear.

Enjoy crawling underneath the dash to access them!
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Re: gas gauge

Post by iloveredmeat »

rwmann wrote: Wed Jul 21, 2021 1:56 pm The slots are on the back side of the combination gauge, at about the 8-o'clock and 7-o'clock positions looking at the gauge from the rear.

Enjoy crawling underneath the dash to access them!
This is such great info!

One more thread that makes this forum invaluable.

Good stuff.

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Re: gas gauge

Post by mraitch »

Great info BTW - never knew.

So I currently have unfettered access to relevant guages , is there anyway of testing/adjusting out of the car??
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