Fuel gauge not reading properly

[annie]

Sent: 11/11/2002 1:12 PM

I have a 1976 Winnebago Chieftain.  When I fill my gas tanks the guage shows 3/4 even though I know they are full.  It does this on both tanks.  Does this mean my gas guage is bad or are both of my tank sensors bad?

Thanks for  any input!
annie   

[Peter T]

Sent: 11/13/2002 8:20 AM

Annie,

It's possible that the tank float is bad.  Still, if the gauge correctly reflects amount in tank from 3/4 down to E, I'd not worry about it too much.  For me, E is more important of a reading than F is

Peter

[denisondc]

Sent: 11/27/2002 9:34 PM

Does your 76 use an instrument panel with a printed circuit sheet for its wiring? I would be suspicious that the "printed" contacts are oxidized and aren't conducting well. I've had poor contact problems with my mopar cars having those printed circuit panels. I get a tube of conducting- paste in an electronic store and use it when I reassemble things. Also I think there is a voltage limiter on the back of the instrument panel - used to provide 5 volts to the gauge. It may be corroded too. denison

[UluzYarx]

Sent: 2/19/2004 12:14 PM

Instrument Voltage Regulator?

[Mental72]

Thanks for all the posts here. I have a '72 Dodge something that has a fuel guage that reads way low. When it's full it may read 1/4, but as it goes down it reads nothing, rather stressful while driving a rig that gets 5mpg at the moment, at best, down hill, with a wind behind us and the moon before us...anyway. I have to tear into both tanks anyway and figure out how to switch tanks and fix that, I don't think they've ever worked.

[DaveVA78Chieftain]

Do not forget there is a 5VDC bi-metal voltage regulator that can create this problem also.

Dave

[Stripe]

Is that the one behind the instrument panel??

[Oz]

Someone else may be able to answer if the applicability of this particular reference will help, but we have an excellent article on troubleshooting chrysler fuel gauges in the member area (1973-75).  Both of the 74s I had did the same thing.  The fuel always showed 1/4 less than actual.  I've read here, many times of others who had the same problem and there is a permanent fix for it... if it's also the same set-up as you have.

[DaveVA78Chieftain]

On the 69 - 73 M-300 and M-375 chassis with the old style instrument cluster, the 5 volt bi-metal regulator is built into the Fuel Gauge.  The article in the members area is discussing this style setup.

Inside of Old Style Panel Fuel Gauge

Dodge went to a printed circuit board style instrument panel in 73 for the RM series chassis.  The voltage regulator is mounted to the printed circuit board on this version.
Here is the procedure for upgrading to a semi-conductor based regulator for this version http://www.allpar.com/history/mopar/electrical2.html

Rear of new style Instrument Panel

For both old and new style setups, Dodge used a 10 ohm to 70 ohm sending unit.

Dave