NEED HELP. Trouble Shooting New Fuel Sending Unit.

GoneLoco99

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I am working on a 68 Crown Coupe Imperial.
•Ohm meter is reading 43.4 ohms @ sending unit when hooked up direct.
•I replaced gas tank with new factory tank from Mopar direct.
•Replaced sending unit with new sending unit from Mopar direct.
•Replaced fuel gauge with new AutoMeter 73/10 4319 fuel gauge.
•Ran new sending unit wires
•Ran new 10-12 gauge ground wire from sending unit to frame on car

AutoMeter gauge past FULL when powered up. I unhood sending wire, and ground it to the chassis, and gauge with read EMPTY.
Any insight would be great. Thank you
 

halifaxhops

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Where is it in the tank? Empt,y full etc? Mopar is 10-73 ohms.
 

Justin Plant

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The ohms resistance must be same between the sender and the gauge at both empty and full. Plug in the old sending unit, see if the problem persists. If it doesn't your new gauge doesn't like your new sending unit. The new ground wire could me messing you up too.
 

GoneLoco99

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The ohms resistance must be same between the sender and the gauge at both empty and full. Plug in the old sending unit, see if the problem persists. If it doesn't your new gauge doesn't like your new sending unit. The new ground wire could me messing you up too.
Without the “ground” wire, the results were the same. That’s why I added the ground wire.
 

GoneLoco99

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Where is it in the tank? Empt,y full etc? Mopar is 10-73 ohms.
Sending unit is currently in the tank. There is between 10-8 gallons of gas in the tank currently

C4272505-89D9-429D-89DE-63F3290EA0B5.jpeg
 

HWYCRZR

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Here is my gauge test tool.

Low or empty 74 ohms, medium or 1/2 23 ohms, high or full 10 ohms. This is what the gauge wants to see to read correctly. I will find a couple of threads that give some options, and rabbit holes I went down.
6F0A2029-2814-427B-9465-F59D50B0741A.jpeg
C3FAB1A1-2E58-44D6-9B8F-7DA703900462.jpeg
 

HWYCRZR

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Ok not using a standard Mopar gauge. Is the sending unit “stock” meaning it thinks it’s going to a Mopar gauge?
 

CBODY67

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New AutoMeter fuel gauge? What resistance does THAT gauge need to work correctly? Why not use the existing in-dash fuel level gauge?

Just curious,
CBODY67
 

GoneLoco99

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New AutoMeter fuel gauge? What resistance does THAT gauge need to work correctly? Why not use the existing in-dash fuel level gauge?

Just curious,
CBODY67
I updated all the gauges (volt, water temp, oil pressure, fuel level) with new AutoMeter gauges.

Gauge is for 73/10 ohm
 

65sporty

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I would pull the sender and test it with a meter. Ohm reading at empty and then sweep it watching the readings to full.
 

Gerald Morris

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My AutoMeter 880785 fuel gauge worked perfectly with a new sending unit. In truth, it works more accurately than the old gauge now in Gertrude, though Trudi's gauge works plenty well enough, once I allow for it hitting "E" when there may be between 5-8 gallons left in the tank. 5 gallons I don't mind, though 8 is a little excessive for a reserve. Mind you, my gauge is advertised specifically for old Mopars, and had a modest price (around $70) from Jegs. Here is the gauge, from Auto Meter:

2 Search for the 880785 by Auto Meter.

And here it is from Jegs:


Here is my posting on what a tits gauge it is:


Get one, and it should work with a good 73-10 sender. I got an OLD sender to even go the range on the gauge, after seeing how nice it played with what I had in Mathilda.
 
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