fuel gauge problem

[oldsnofear]

HI I GOT A NEW SENDER AND JUST HAD AUTO INSTRUMENTS RESTORE THE CLUSTER WHEN I UNPLUG THE WIRE AT THE UNIT IT GOES TO  E WHEN I GROUND IT IT GOES TO FULL. THE GAUGE READS ONLY 1/4 TANK AND ITS GOT 17 GALS OF FUEL IN IT.  THE SENDER IS READING 19.1 OHMS. SHOULD I HAVE 5 VOLTS ON THE SENDER WIRE UNPLUGGED?? HELP THANKS

[Topher]

Yes, you should.

[maxwellwedge]

Where did you buy it?

See this post.

http://www.dodgecharger.com/forum/index.php/topic,54263.msg604278.html#msg604278

[oldsnofear]

year one about a year ago.from what i make out of the manual 10 ohms is full and 75 ohms is empty. my sender shows 19 ohms on the fluke meter which should read over 3/4 right?? the gauge only reads 1/4 and if i ground out the wire it goes to full???

[y3chargerrt]

You have the ground strap on the sending unit?

[tachman]

tachman here:
sounds like the gauge needs calibrated or you need my 5 volt solid state limiter, check out www.tachman.com/mopar and www.tachman.com and click on troubleshot and and see how to check out your gauges.
tachman

[tachman]

sorry mates:
the correct url to my my mopar page is www.tachman.com/mopar.htm its late and time to get some sleep
tachman
1-800-327-8716 m-f 9-6 e.s.t

[oldsnofear]

Sending unit and fuel tank are grounded properly......Thanks

[69chargerR/T]

HI I GOT A NEW SENDER AND JUST HAD AUTO INSTRUMENTS RESTORE THE CLUSTER WHEN I UNPLUG THE WIRE AT THE UNIT IT GOES TO  E WHEN I GROUND IT IT GOES TO FULL. THE GAUGE READS ONLY 1/4 TANK AND ITS GOT 17 GALS OF FUEL IN IT.  THE SENDER IS READING 19.1 OHMS. SHOULD I HAVE 5 VOLTS ON THE SENDER WIRE UNPLUGGED?? HELP THANKS

I just spent a week trying to fix my fuel gauge, this is what I found out.

Some after market fuel senders will not read right, some fuel senders utilize a linear movement, are original fuel senders utilize a non-linear movement. here is how you tell. remove your fuel sender from the tank, hook up your ohm meter, if its a non-linear sender this is what it should read.

full 10 ohms
half 25 ohms
empty 50 ohms
pointer width below E 73 ohms

A linear sender will read this

full 10 ohms
half 41 ohms
empty 73 ohms

The key is to make sure the sender you have reads 25 ohms when you have the float arm half way between the stops.

I had got an after market sender from an auto parts store that I deal with and it would not read right. Because it read 41 ohms when the float arm was at half.  I hear some guys bend the float arm, but theres no way you can bend the float arm that much to make it read 25 ohms when the tank is half full.

If your sender reads 25 ohms at half then it should read right.  What you have to check is to make sure the filter on the end of the sender is on the bottom of the tank. Mine was not, so I had to bend the tube above the sender so the its on the bottom of the tank.   


If your sender does read 25 ohms at the half way point, put 10 gallons  of gas in the tank and it should read half on the gauge. If it  reads less than half, then the filter or pick-tube is not on the bottom of the tank. Then you will have to bend the tube like I said above.  Alan




PS: this is what I did with my fuel sender, and after all this it now reads perfect.

[oldsnofear]

THANKS FOR THE INFO. I HAVE TO BURN SOME FUEL OUT TO PULL THE SENDER,, BUT IF I HAVE A 19 OHM READING AT THE SENDING UNIT (WITH 17 GALS OF FUEL I JUST PUT IN A 19 GALLON TANK) MY GAUGE SHOULD STILL READS 1/4 TANK  19 OHMS=7/8 TANK ??     10 OHMS FULL AND 75 EMPTY RIGHT? 

[Dodge Don]

HI I GOT A NEW SENDER AND JUST HAD AUTO INSTRUMENTS RESTORE THE CLUSTER WHEN I UNPLUG THE WIRE AT THE UNIT IT GOES TO  E WHEN I GROUND IT IT GOES TO FULL. THE GAUGE READS ONLY 1/4 TANK AND ITS GOT 17 GALS OF FUEL IN IT.  THE SENDER IS READING 19.1 OHMS. SHOULD I HAVE 5 VOLTS ON THE SENDER WIRE UNPLUGGED?? HELP THANKS

I just spent a week trying to fix my fuel gauge, this is what I found out.

Some after market fuel senders will not read right, some fuel senders utilize a linear movement, are original fuel senders utilize a non-linear movement. here is how you tell. remove your fuel sender from the tank, hook up your ohm meter, if its a non-linear sender this is what it should read.

full 10 ohms
half 25 ohms
empty 50 ohms
pointer width below E 73 ohms

A linear sender will read this

full 10 ohms
half 41 ohms
empty 73 ohms

The key is to make sure the sender you have reads 25 ohms when you have the float arm half way between the stops.

I had got an after market sender from an auto parts store that I deal with and it would not read right. Because it read 41 ohms when the float arm was at half.  I hear some guys bend the float arm, but theres no way you can bend the float arm that much to make it read 25 ohms when the tank is half full.

If your sender reads 25 ohms at half then it should read right.  What you have to check is to make sure the filter on the end of the sender is on the bottom of the tank. Mine was not, so I had to bend the tube above the sender so the its on the bottom of the tank.   


If your sender does read 25 ohms at the half way point, put 10 gallons  of gas in the tank and it should read half on the gauge. If it  reads less than half, then the filter or pick-tube is not on the bottom of the tank. Then you will have to bend the tube like I said above.  Alan




PS: this is what I did with my fuel sender, and after all this it now reads perfect.

The service manual says the sending unit should read 73 ohms (+/- 12 ohms) at the empty position and 9.6 ohms (+/- 1 ohm) at full position. I just tested a new sending unit with these same results as specified in the service manual.

[69chargerR/T]

THANKS FOR THE INFO. I HAVE TO BURN SOME FUEL OUT TO PULL THE SENDER,, BUT IF I HAVE A 19 OHM READING AT THE SENDING UNIT (WITH 17 GALS OF FUEL I JUST PUT IN A 19 GALLON TANK) MY GAUGE SHOULD STILL READS 1/4 TANK  19 OHMS=7/8 TANK ??     10 OHMS FULL AND 75 EMPTY RIGHT? 

Did you disconect the wires from the sending unit when you got that 19 ohm reading. You have to disconect the two wires to get a correct ohm reading.

[69chargerR/T]

Dodgedon, what does the sender you have read with the float arm half way between the stops. It needs to read around 25 ohms to work right. The after market sender I had read right at full and empty but not at the half way mark. I sent that sender back and used the one that was in the car, because that one read right. From what I found out all the sendars will read right at full and empty, but will not read right at half ( 25 ohms ).

[oldsnofear]

it was 19 ohms with no wires hooked up. i have to wait for the michigan weather to break so i can burn up some fuel thanks shawn

[Dodge Don]

Dodgedon, what does the sender you have read with the float arm half way between the stops. It needs to read around 25 ohms to work right. The after market sender I had read right at full and empty but not at the half way mark. I sent that sender back and used the one that was in the car, because that one read right. From what I found out all the sendars will read right at full and empty, but will not read right at half ( 25 ohms ).

I pulled the sending unit out again and re-tested. Approximately 10 ohms at full stop position and approximately 70 ohms at empty stop position. Putting the float at half way between both stops gave me a reading of just over 30 ohms. The readings were smooth as I transitioned from full to empty. I think I'm good.

[69chargerR/T]

it was 19 ohms with no wires hooked up. i have to wait for the michigan weather to break so i can burn up some fuel thanks shawn

If you have 19 ohms and 17 gallons in the tank your gauge should read around 3/4 or more   You'll have to run some gas out of it, or siphon some out.  When you have around 8 or 10 gallons in it you can take the fuel sender out with out any gas spilling out.

When you get the sender out hook a long jumper wire to the fuel gauge sender wire so have the sender in the car so you can watch the gauge. hook another long jumper wire to the - battery terminal to ground the sender. This is what I did so I could move the float arm and watch what the gauge reads when I moved the float arm.  You need to move the float arm to full and see if your gauge will read full. When the float arm is at empty the gauge should read below E.  Good luck, Alan

[69chargerR/T]

Dodgedon, what does the sender you have read with the float arm half way between the stops. It needs to read around 25 ohms to work right. The after market sender I had read right at full and empty but not at the half way mark. I sent that sender back and used the one that was in the car, because that one read right. From what I found out all the sendars will read right at full and empty, but will not read right at half ( 25 ohms ).

I pulled the sending unit out again and re-tested. Approximately 10 ohms at full stop position and approximately 70 ohms at empty stop position. Putting the float at half way between both stops gave me a reading of just over 30 ohms. The readings were smooth as I transitioned from full to empty. I think I'm good.

Dodge Don, you should be good   Put around 8 to 10 gallons of gas in and you gauge should read half or close to it. If it reads less than half ( mine read 1/4 ) then the sending unit is not on the bottom of the tank. Take the sender back out and bend the senders tube down ( make sure you bend the tube above the float ) put the sender back in and see where your gauge reads now. That what I had to do with my sender

[tachman]

Yes, you should.

tachman here:
all mopar fuel, temp and oil gauges have the following values: 10 ohms is low side, 80 ohms is high side of gauge markings. want your gauges calibrated correctly check out my test equipment at www.tachman.com. other restoration shops do not print the part numbers on the speedo, tach and gauges. if you want the best in authenticity for you charger cluster restorations have a look at www.tachman.com/mopar.htm and see for your self. any questions about your charger instruments just email me at tachman@bellsouth.net or call toll free 800 327 8716 m-f 9-6 est. be glad to help.
tachman :

[Corellian Corvette]

OK now I'm confused. 

My current sending unit (a Stainless 3/8 unit from a source I don't recall), I can't tell if it reads right or not. I fidgeted with it, it now reads F when the tank is full, and if I fill up the tank on "E", I have to add about 14-15 gallons. I did not do a resistence test on this unit. It appears like this unit reads slower as the tank empties. It also looks like E = E, as letting the guage get right to "E" I could hear my fuel pump struggling to get fuel. 

SO I just got a sending unit from Roger Gibson Auto restorations, which according to this post, is supposed to read right

http://www.dodgecharger.com/forum/index.php/topic,54263.0.html

I did the resistance test on that unit tonight, and these are the readings I get with the float arm at 1/4 distances from HIGH to LOW.

OHM - Arm Position
.09 = HIGH
.19 = 3/4
.35 = 1/2
.55 = 1/4
.77 = LOW

I also hooked it up to the wire in the car, grounded the unit, and tested it against against the real guage. Here's where the Guage reads relative to the position of the arm.

Arm - Fuel Guage Reading
LOW = slightly below E
1/4 = slightly above E
1/2 = about 1/4 tank
3/4 = Slightly above 1/2 tank
HIGH = F

As you can see, placing the arm 1/2 way in the middle of travel does NOT get you 1/2 tank. 1/2 tank has the arm a little more than 1/4 the way off the top.

Is this going to work right? Meaning - what position should the ARM be on the sending unit relative to the GUAGE reading? I'm sure 1/2 tank is NOT 1/2 arm position given the shape of the tank. My readings are not super conclusive as they are not exactly like the "linear" and "non-linear" results 69chargerR/T lists.

 

[69chargerR/T]

corellian corvette, put around 8 to 10 gallons of gas in the tank and see what your gauge reads. It should read around half a tank.

[Paul w]

  Hi guy's and happy Easter   I had the same issue when I fitted a new sender, what I did was too empty the gas tank then refill it with three gallons of gas, then pull the sender and adjust the float level by bending the float arm until the gauge read 1/4 tank. Then I put another three gallons of gas in and the gauge read 1/2 a tank. This means you will not run out of gas as you will always have a little in the tank.
PLEASE DON'T FORGET THAT THIS IS BRITISH GALLONS and NOT US. and the Charger gas tanks only take 15 British gallons and not 19 US.

[oldsnofear]

OK I PULLED THE SENDER OUT OF THE TANK IT IS GOOD 9.8 OHMS FULL AND 74.8 ON EMPTY. I WENT TO RADIO SHACK AND GOT A 10 OHM RESISTOR AND HOOKED IT UP AT THE DRIVERS SIDE KICKPANEL CONNECTOR AND IT READS 3/4 TANK THE GAUGE MUST BE OUT OF CAL LATER SHAWN PS THANKS FOR ALL THE INFO