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Hello all. I have a 1998 Honda Civic DX hatchback with 125,000 miles. Recently my gas gauge started rising steadily until it goes to the full mark. It does this intermittently. If I'm driving for a bit I will also notice that it will fall back to its correct position.

I figured the best place to start would be checking the fuel sending unit. That is what I am thinking but what do you guys think? Any other suggestions on what to check?

Either way, does anyone know where I can find the resistances for the fuel sending unit of a 98 civic. If I could find that, I could hook up a resistor and check to see where the corresponding gauge position is located. That should help me narrow it down. Thanks.

 
Rep Power: 518

Here's the info I found:

Locate sending unit wiring on top of the tank. (there is an access plate on floor)
Disconnect 3 p connector from sending unit.
Connect voltmeter to black and yel/blk wire, turn key on, reading should be 5-8 volts.



Sending unit specs: I see 2 different sets of specs. One for Japan built cars and another for US and Canadian built.

US/Can F = 3.5-5 ohm, 1/2 = 29.5-35.5 ohm, E = 105-108 ohm
Jap: F = 2-5 ohm, 1/2 = 25.5-39.5 ohm, E = 105-110 ohm
Yeah, that's what is printed in my book.


There's a big warning about shorting the wires at the sender connector during testing, apparently if you leave it shorted too long it can overheat and damage the gauge.
One of the tests is to use a jumper wire to short the 2 terminals, and turn the key on (briefly), see that the gauge is heading for the full mark, then shut the key off so you don't damage the gauge.


HTH

 
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Thanks man, I really appreciate the help. I was having trouble finding this. Also, that sounds like a handy book. Is it a service manual? I have been trying to find a good detailed service manual. Do you have one to recommend?

 
Rep Power: 518

Factory service info.