fuel gauge does not read correctly

[Cratos]

having same problems I have two sending units both ohm close to spec but the gauge is ways off with 19 gal in it reads 1/4 with 5 it reads empty cant get it to read full in the tank if I use a 12 v battery to power it it reads fine in all positions????

[Mopar5]

Be careful with 12 volts on the guages wouldnt do it very long more than a second or two.

[Cratos]

could it be the voltage limiter when i put a meter on the blue wire to the sender it jumps all over the place???

[Scooter]

thanks, all good info, I just ordered a meter match , we'll see how that works

Ok.. it's been a month... what gives!

Didya get it installed?

[chargerdon]

Problem is one of    things:
1) Sending unit not giving correct OHMS.   To check, take the sender wire off of the fuel gauge and measure its ohms...   Empty tank should read about 73 Ohms, 1/2 tank 22 ohms, and full tank 9.6 ohms     (according to the info i got for gauges from http://www.66-67charger.com/sourceguide/ )   So if with a full tank your not getting around 9-10 ohms then:
a)  the problem is from the sender in the tank to the gauge.  Go right to the tank and measure the ohms right at the post for the fuel sender with its wire disconnected...   If good there then your wiring is suspect.   
b) Sending unit itself could be bad, but you said you tested it.   I assume out of the tank...   It could be that sending unit simply needs to be adjusted.   If might be that the float is not causing the arm to Not fully travel.   If this is the case  drain tank first, remove the float and bend the arm so that when in upright top position it causes the arm to fully travel. 


If Getting correct Ohms at the gauge then:

2) Low voltage into the gauge...  take off the positive wire and check with multimeter...it should be around 5-6 volt.   If low then the voltage regulator needs replaced...   it is located on the back of the gauge cluster.    If it is in the 5 to 6 volt range then:

3) Gauge itself might be bad...   simple test ...   remove the sending unit wire and put solid ground to it instead...   with key on it should swing to full....   if it doesn't gauge is bad.   

Has to be one of those problems...   

PS...the voltage regulator also feeds the temperature gauge...does your temperature gauge read correctly ??