LP tank gauge not working

[Bob Dunahugh]

The gauge on our 78 Royale hasn't functioned since I got everything back together. Didn't check for function prior to disassembly. Short version. Too much mouse shit to deal with. Wirings checked, and now in a conduit. So what ohms readings should I look for?

Bob Dunahugh

78 Royale.

 

[roy keen minden]

I believe all the float rheostats including that propane,gas and water tanks are the standard GM 1970's 90 ohms. If you need to repair or replace the
propane gage unit you will haven to run the furnace or other high use appliance for a time to use up the propane in the tank before removing the gage
from the tank but you already knew that.
--
Roy Keen
Minden,NV
76 X Glenbrook

 

[LarryW]

HI Bob,

Mine did not work from the time we bought it in 2003. Spent many hours trying to figure out why. Just last summer building my new dashboard, I had to
wire in the new dash fuel gauge. Checking the instruction sheet on the new gauge, it has three connections, one from 12v power, another from the tank
sending units, and the third is a direct ground. It suddenly occured to me that I did not remember seeing that third wire from the gauge...the
ground. Went back to the LP gauge and found it did not have one. Somehow a PO had removed it. I added the ground and 13 yrs later I finally had a
working LP gauge. Lesson to be learned.....check the ground connection, which is usually the center of the three posts. HTH
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.

 

[JHeslinga]

Is the Tank Grounded properly? Gauge won't work if not. If gauge is pegged on full then no ground. (or wire open) run Temp wire from sender body
to good ground to confirm.

if the gauge is pegged on empty then wire is shorted to ground somewhere.

--
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta

 

[Bob Dunahugh]

My LP tank has 2 wires to it. A red, and a white. That's the same as our other 78 Royale.
Bob Dunahugh

________________________________
From: Bob Dunahugh
Sent: Thursday, November 24, 2016 11:41 AM
To: gmclist
Subject: LP tank gauge not working

The gauge on our 78 Royale hasn't functioned since I got everything back together. Didn't check for function prior to disassembly. Short version. Too much mouse shit to deal with. Wirings checked, and now in a conduit. So what ohms readings should I look for?

Bob Dunahugh

78 Royale.

 

[LarryW]

> My LP tank has 2 wires to it. A red, and a white. That's the same as our other 78 Royale.
> Bob Dunahugh

Right...but at the gauge there is a third wire. There are three posts on the gauge. On mine, the center post is a ground for the gauge. It is
refered to "balancing...something". can't remember what the something is. look at the back of the gauge, should be three posts.
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.

 

[emerystora]

Some gauges such as Bob's have two wires but the case of the gauge grounds to the tank so it is important that the tank be grounded to the frame to have the gauge work properly. The tank could have a wire to the frame or it could be grounded by the bolts holding it down to the frame.

Emery Stora

>

>> My LP tank has 2 wires to it. A red, and a white. That's the same as our other 78 Royale.
>> Bob Dunahugh
>
> Right...but at the gauge there is a third wire. There are three posts on the gauge. On mine, the center post is a ground for the gauge. It is
> refered to "balancing...something". can't remember what the something is. look at the back of the gauge, should be three posts.
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[wrightjohn 2646]

Should be 0-90 ohms as all the sensor are 0-90 from the factory.

JR Wright

>
>
> My LP tank has 2 wires to it. A red, and a white. That's the same as our other 78 Royale.
> Bob Dunahugh
>
> ________________________________
> From: Bob Dunahugh
> Sent: Thursday, November 24, 2016 11:41 AM
> To: gmclist
> Subject: LP tank gauge not working
>
>
> The gauge on our 78 Royale hasn't functioned since I got everything back together. Didn't check for function prior to disassembly. Short version. Too much mouse shit to deal with. Wirings checked, and now in a conduit. So what ohms readings should I look for?
>
> Bob Dunahugh
>
> 78 Royale.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[Bob Dunahugh]

So if I ground the tank. The gauge in the wall control panel should work?

Bob Dunahugh

78 Royale.

 

[emerystora]

Not necessarily. It might. However it could also be a bad gauge or bad connections. But it's worth a try.
Also, remove the gauge and clean beneath it and clean the bottom of the gauge.

Emery Stora

>
> So if I ground the tank. The gauge in the wall control panel should work?
>
> Bob Dunahugh
>
> 78 Royale.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[thomas phipps]

Happy Black Friday. Now, will that 42" smart TV fit?

More seriously, amazing how many problems are related to bad or non-existent grounds. Drive you to using rough language.
Tom, MS II
--
1975 GMC Avion
KA4CSG

 

[RJW]

> The gauge on our 78 Royale hasn't functioned since I got everything back together. Didn't check for function prior to disassembly. Short version.
> Too much mouse shit to deal with. Wirings checked, and now in a conduit. So what ohms readings should I look for?
>
> Bob Dunahugh
>
> 78 Royale.

While this might not apply to your situation, since you have a Royale, my LP gauge never really worked for the first 17 or so years that I had my Palm
Beach. The gauge on the tank and the reading on my monitor panel always matched, but the readings had no real correlation to what was in the tank.
Once I switched out the tank sender with a known good one someone gave me, still the same. I had always suspected that the sender in the tank was
messed up. I was going to use a "GMC Round To-it" someday to remove the tank and have someone open it up and fix or replace the sender. Fortunately,
I never got around to doing that job.

About a year ago, while I was fooling around with something unrelated in the LP gas compartment, I happened to notice that the external sender did not
look like it was completely seated in the recess on the tank. It looked to be about 1/16" off of being all the way in. It had always looked OK to my
untrained eye, but that day I thought about the fact the sender inside the tank and the one outside the tank are magnetically coupled and that perhaps
too big of a gap could cause problems. To make it fit better I decided to sand down the circumference of the sender (I had a spare so I was not
worried about messing it up) just enough to get it seated all the way. As soon as I pushed it in and hooked up the wires the reading on the gauge went
to showing ~80% full (I had just had the tank filled) from the close to empty that had been showing before. For the past year, the gauges
consistently match pretty closely to what is actually in the tank.

To think that I went over 17 years without a functioning LP gauge when all along the problem was that the senders on the tank were never seated
properly because they were slightly too big around to fit in the tank. It's a good thing I never went to the trouble of taking the tank out and having
the internal sender "fixed" or replaced. That sure would have been a waste of time and money.

--
Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com


Coop Roller Cam 455, Howell TBI + EBL, 3.42 FD, Quadra Bag, Macerator, Manny Tranny etc.