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fuel guage

fuel guage
C

cjnewbie

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Location
plainfield indiana
Vehicle(s)
79 cj7 360 3 speed
I am trying to get my fuel guage working i put the new sender in the tank and still nothing it was kind of stupid but i never even looked at the back of the guage but now i have and there are no wires to it :mad: but moveing on i assume 1 post on the guage should be 12 volts the other should go to the sender is this correct? somebody please help thanks
 
This is from my 78 shop maual wiring diagram...
Pink wire from tank sender to one side of guage and a red wire to other connection on guage.
looking at the rear of the cluster pink wire on the left, red on the right with a common ground running between fuel and temp guages.
 
this may be a stupid question but do the acctual gauges go bad ? i have power a good ground and a new sender and still nothing
 
If you have a ground wire attatched take it off and just let the gauge ground through the gauge cluster housing. I know it sounds a little weird but it was the only way I ever got my fuel gauge to work.
 
Gauges DO go bad occasionally... but the first thing to be sure of is that the three wires (12V, the one to the tank, and the regulated voltage to the temperature gauge) are connected CORRECTLY. There's only ONE way they'll work right - swap 'em and it won't work. Wire it entirely incorrectly and you can fry not only the gauge but the tank sending unit, too.

The fuel gauge contains a voltage regulator that delivers regulated power to the temperature gauge, as well as regulating its own voltage. If the regulator burns up, neither gauge will work. In that case, it's time to get another gauge... but you'd better test your sending unit now to be sure it didn't get fried...
 
TDHofstetter said:
Gauges DO go bad occasionally... but the first thing to be sure of is that the three wires (12V, the one to the tank, and the regulated voltage to the temperature gauge) are connected CORRECTLY. There's only ONE way they'll work right - swap 'em and it won't work. Wire it entirely incorrectly and you can fry not only the gauge but the tank sending unit, too.

The fuel gauge contains a voltage regulator that delivers regulated power to the temperature gauge, as well as regulating its own voltage. If the regulator burns up, neither gauge will work. In that case, it's time to get another gauge... but you'd better test your sending unit now to be sure it didn't get fried...
Click to expand...

Also loosing the ground on the dash can make the regulator stop working and burn up the gauge and the sending units. For some strange reason B&W saw fit to make the thing continuously put out power when the ground was remove. Maybe to keep it universal so it will work with either negative or positive ground.

Look at the links Brock posted for more info.
 
you can also try...
assuming your wiring is correct
take the back of your gauge off then make sure on the back of your fuel gauge the metal points are not touching the metal points on your speedometer cluster.
it has to be centered in order for your gauge to work.
this happened to me once and i did that and my gauge worked perfectly.
hope i helped.:cool:
 
cjnewbie said:
this may be a stupid question but do the acctual gauges go bad ? i have power a good ground and a new sender and still nothing
Click to expand...

IMHO Jeep gauges problem are usually ground issues, corrosion or both.
Sometime P.O. hack jobs.;)
 
the new sending units sold by many auto repair places are JUNK
twice i have found the float ball to be full of gas! if it don't float
it don't work.

does anyone know of a GOOD aftermarket sending unit with a
solid float? (can't fill with gas)

corrosion can be dealt with dielectric grease. not cheap but
in wet environments can stave off corrosion.

radman
 
You can fix a leaky float...

First, dry it out inside.

Second, chill it (deep freeze) and immerse it in hot water. The air inside the float will expand, pressurize, and bubble out in the leaky spot, making the leaky spot easy to find. Mark the leaky spot, let the float cool off to room temperature (or a little cooler). Coat the leaky spot with a dab of silicone or epoxy. Once it's sealed, it's fine.

Or... just replace the float with any other material that's lightweight, nonporous, and not oil-soluble. That eliminates most (but not all) plastics. Anybody know if polyester is oil-soluble? If not, that'd be a good approach... inflate a small rubber balloon to about the size of the float, and coat it with fiberglass resin (without the actual fiberglass). That'd make a hollow polyester bubble, which can be attached to the float arm with more resin or epoxy. Ugly, but who's counting?
 
gonna give the float a freeze and heat.. sounds like a great idea!
but it seems that these floats are suspect (this is the second float
to fail!)

thanks.. radman
 
cjnewbie said:
I am trying to get my fuel guage working i put the new sender in the tank and still nothing it was kind of stupid but i never even looked at the back of the guage but now i have and there are no wires to it :mad: but moveing on i assume 1 post on the guage should be 12 volts the other should go to the sender is this correct? somebody please help thanks
Click to expand...
to CJNEWBIE from another newbie

I just put up some captured web pages about diagnostics of Jeep CJ gauges in the DOCS section. If, like me, you didn;t know this section was there, look at the top of the home page right under the orange CJ FORUM logo graphic.

I have the same problems with an '80 CJ7 , but by fixing my grounds, testing with an ohm meter, then methodically tracing the circuit end-to-end, I know I can fix them.

Of course, I'll likely wait until it is 100 degrees in the garage!

bonne chance
 
I may've missed something... or maybe I'm just not flashin' on how the "Docs" section works... but I don't see any attachments - just the description.
 
TDHofstetter said:
I may've missed something... or maybe I'm just not flashin' on how the "Docs" section works... but I don't see any attachments - just the description.
Click to expand...
Tim, I input 5, 4 PDF and 1 jpg. I waited until all five showed up on the message drafting panel, then pulled the trigger,

I can find John Strenk's article on my post, but not the other 4.

Not the first time this has happened. I'll go back and see if another input will get the four previous ones. Some of it is redundant, but one piece will shine a light into one dark place, the next piece, another different dark place.
 
Interesting - I can't see any of 'em there.

The Strenk articles are EXCELLENT. I've spoken with John a time or two to straighten out a couple of minor details in those articles (I'm a compulsive proofreader). He's really gone above & beyond to write 'em... and even I use 'em for reference now & then.
 
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