Please help. Fuel gauge/sender unit

[firiepete]

:hello2: I'm new to B Bodies. I'm in Melbourne Australia. My Mopar is 1968 Dodge Coronet R/T 440 which I love. A question if I may.

Having problems with my fuel gauge/sender unit. When tank is full gauge reads 1/4 - 1/2.

I have removed tank from car and checked sender unit for OHMS resistance being 10 - 75 ohms, which I understand is within the limits. Also I bent the float arm. Worked out that the float arm was too long and hitting the top of the tank.

Have checked ohms with tank full. Reads 35 ohms. Could the problem be as simple as a faulty new sender unit??

So, still no luck and at my wits end. :headbang:

Could the resistor on the dash panel be faulty.

Thanks. Regards, Pete.

p.s. I will post a pic of my Mopar when I work out how to do.

 

[eric383]

Welcome Pete. Here is some reading for you about our gauges. It is for 1966 but it should apply to you. Also is it possible that the float is saturated and not allowing it to properly move the arm to the top when full? If you take the lead off the tank and ground it for a second or two your gauge should read full. have an assistant look at the gauge while you ground out the lead. Just do it for a few seconds so you don't harm the gauge or get a 10 ohm resistor and use that for the test. Good luck.

 

[firiepete]

Thanks Eric. I have checked the gauge the way you explained. Gauge works fine. I have come to the conclusion I need to replace the sende unit even though it is only 2yrs old. Where can I buy a quality piece??
Regards,, Pete

 

[slepr1]

I just installed a new fuel sender in my 77. It was from ebay and cost $40. I was skeptical before buying it because comparable ones range from $80-$140. I researched on this forum if anyone else tried cheaper ebay senders which came up positive and for $40 with free delivery I took the chance. I've only had one cruise in it so far since the install and the gauge seemed a bit inaccurate at times. At start up the gauge read just over half full. During my cruise the gauge dipped down to just above 1/4 full and was occasionally showing between 1/2 and 1/4. When I parked the car it read just below half which seemed correct. Why the movement is beyond me.

 

[eric383]

I have not had to replace mine so I can't comment on where to buy a quality sending unit. Try posting a question in the electrical sub forum. Good luck.

 

[Budnicks]

welcome to FBBO
maybe post your questions in the general discussion forum,
or somewhere other than the welcome wagon,
you'll get more opinions & help probably...

If you park on a hill up or down it will read differently also, changes the float level...
You may have to try to bend the metal rod with the float some too,
to get the correct ohm readings, at the proper level...

good luck

 

[firiepete]

Thxs Budnicks. I have tried bending metal rod etc. My next job is to replaced resistor on the printed circuit. It may be faulty. Pete.

 

[furyus]

Before you do that, do you have the ground strap on the fuel line? Sending unit must be grounded.

 

[firiepete]

Hi Furyus. I found the proper earth strap from a dealer. Will buy ($22.00 AUS) and try that. Thxs. Pete