Faulty Fuel Guage Diagnosis?

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nowmopardave

nowmopardave

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Good morning,
Fuel guage not working on Deb's Duster. Shop manual shows how to diagnose with Mopar test tool/ My question is how to test guage & sending unit with regular tools to determine where the problem lies. Any suggestions would be appreciated.

Thanks,

Dave
 

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Take the wire off the sender and ground it. With the key turned to run, the gauge should goto full. If not, then the trouble is on the gauge side. If it does, then the trouble is either the jumper strap between the steel fuel line over the rubber hose to the sender (most common failure point) or the sender. Test the sender with a voltage ohm meter. Should get readings somewhere between 85 to 10 ohms or thereabouts.
 
Do a search on this forum, there are tons of threads about gauge problems


The Mopar test box is basically a resistor substitution box. You can buy some resistors at Radio Shack and hook them in place of the sender. Both temp, fuel (and oil in some cars) are the same resistance, so one set of three resistors can check all three gauges.

Full is about 10-11 ohms, 1/2 is 23-25 ohms, and empty is about 73 ohms

For example, for the 1/2 scale, buy a pack of four - 100 ohm, 1/2 watt resistors at radio shack. Wire all 4 in parallel, which will then be a 25 ohm, 2 watt resistor, in effect. Buy a bag of clip leads while you are there. Cut three of them in half, and solder "a half" a clip lead to each of your resistors.

Hook one resistor at a time from the sender wire connection to ground. You can try this with the temp, first, as it's easy to get to. Check with engine running, and give it "a minute" for the gauge to fully stabilize.
 
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