Fuel gauge not working, but all other are true...See 2 pics...

[gwizzar]

Just wondering if any one with some background sees anything that stand out as an obvious issue and needs addressed. Do the connectors look like they should be replaced..corrosion or poorly crimped? Thank you for your time.

 

[tpenfield]

Re: Fuel gauge not working, but all other are true...See 2 pics...

Looks OK . . . the fuel gauge is not part of the schematic wiring, but it looks like the pink wire leading from the gauge is what goes to the sender.

The issue may be at the sender, not at the gauge. Make sure the wiring is in good shape and complete at the sender.

Caution is the word, since you are dealing with fuel.

 

[gwizzar]

Re: Fuel gauge not working, but all other are true...See 2 pics...

Looks OK . . . the fuel gauge is not part of the schematic wiring, but it looks like the pink wire leading from the gauge is what goes to the sender.

The issue may be at the sender, not at the gauge. Make sure the wiring is in good shape and complete at the sender.

Caution is the word, since you are dealing with fuel.

Yes, pink goes to the sender. I am not going to mess with the sender since it is NOT accessible in the least bit. How might I check the fuel gauge for functionality/continuity? I guess where would I place the reads on the meter is what I am asking. Thanks!

 

[CraigBarnard]

Re: Fuel gauge not working, but all other are true...See 2 pics...

If a marine fuel guage works the same as an automotive unit then the test is fairly simple.
If you ground the wire that leads to the sending unit the guage should slowly move towards the empty reading.
If the wire to the sending unit is "open" unattached to anything it should move towards full.
Or visa versa of my description.
Either way if you see two opposing actions of the needle depending on which way its hooked up then you know the guage is funtioning and the problem is most likely in the sending unit.
They can be tested too but you need to remove it from the tank to do so.

 

[gwizzar]

Re: Fuel gauge not working, but all other are true...See 2 pics...

If a marine fuel guage works the same as an automotive unit then the test is fairly simple.
If you ground the wire that leads to the sending unit the guage should slowly move towards the empty reading.
If the wire to the sending unit is "open" unattached to anything it should move towards full.
Or visa versa of my description.
Either way if you see two opposing actions of the needle depending on which way its hooked up then you know the guage is funtioning and the problem is most likely in the sending unit.
They can be tested too but you need to remove it from the tank to do so.

Sweet! Going to test it in a bit. Thanks for the reply (info), Craig!

 

[NYBo]

Re: Fuel gauge not working, but all other are true...See 2 pics...

It's actually the reverse. Grounding (well, you are really connecting it to the battery negative side) the sender terminal will peg the gauge to the full side. Do this only long enough to verify the needle does this or you can burn out the gauge.

 

[gwizzar]

Re: Fuel gauge not working, but all other are true...See 2 pics...

It's actually the reverse. Grounding (well, you are really connecting it to the battery negative side) the sender terminal will peg the gauge to the full side. Do this only long enough to verify the needle does this or you can burn out the gauge.

geez, great... I have the battery disconnected since I'm re-routing a cluster@uck of wires:facepalm:

 

[gwizzar]

Re: Fuel gauge not working, but all other are true...See 2 pics...

It's actually the reverse. Grounding (well, you are really connecting it to the battery negative side) the sender terminal will peg the gauge to the full side. Do this only long enough to verify the needle does this or you can burn out the gauge.

So I can just take the pink (sender) wire of the gauge and touch it to... geez, i have the starter, alternator out:facepalm: Can I do this if the battery isn't hooked up....confused.. thx

 

[Silvertip]

Re: Fuel gauge not working, but all other are true...See 2 pics...

If a marine fuel guage works the same as an automotive unit then the test is fairly simple.
If you ground the wire that leads to the sending unit the guage should slowly move towards the empty reading.
If the wire to the sending unit is "open" unattached to anything it should move towards full.
Or visa versa of my description.
Either way if you see two opposing actions of the needle depending on which way its hooked up then you know the guage is funtioning and the problem is most likely in the sending unit.
They can be tested too but you need to remove it from the tank to do so.

NO! The gauge does not work that way. Grounding the send lead represents 0 ohms to the gauge and it reads FULL and it will do so QUICKLY so this should be quick touch to ground. Prolonged grounding can trash the gauge. Fuel senders for marine use are 33 ohms full, 109 ohms (roughly) at 1/2 full, and 240 ohms at empty. Disconnect the pink wire and measure resistance from it to ground. If you know roughly how much fuel is in the tank you should be able to tell from the resistance reading if the sender is ok. If you get no reading, then the pink wire is suspect or the sender is bad or its ground at the tank has come undone.

 

[gwizzar]

Re: Fuel gauge not working, but all other are true...See 2 pics...

NO! The gauge does not work that way. Grounding the send lead represents 0 ohms to the gauge and it reads FULL and it will do so QUICKLY so this should be quick touch to ground. Prolonged grounding can trash the gauge. Fuel senders for marine use are 33 ohms full, 109 ohms (roughly) at 1/2 full, and 240 ohms at empty. Disconnect the pink wire and measure resistance from it to ground. If you know roughly how much fuel is in the tank you should be able to tell from the resistance reading if the sender is ok. If you get no reading, then the pink wire is suspect or the sender is bad or its ground at the tank has come undone.

1) You posted, "Disconnect the pink wire and measure resistance from it to ground." I should remove the pink sending wire and do what exactly with my tester? A pic of my tester is attached. Thx! 2) I have the wires going to and from the fuel gauge to the sender unit attached. However, nothing is on either the positive or negative battery terminals since I am re-routing with a new engine harness. Can I place the battery back in the boat and hook up only my ground wires to the negative battery terminal to try this? Side-note: the tank is nearly full so I should be looking for around 30 or so ohms, right? Thank you for your time.

Got it! Only need to know about hooking up the battery. Thanks!
1. Plug the RED test lead into the "W" jack of the multimeter;
plug the BLACK test lead into the "COM" jack.
2. Set the meter’s Function/Range Selector Switch to the "W"
range function (see Controls and Indicators, Item 3).
NOTE: To obtain accurate readings, disconnect at least one
side of the item under test from the circuit or circuit board before
measuring resistance.
3. Place the RED test lead onto one side of the item being tested
and the BLACK test lead onto the other side of the item.
(Polarity does not matter when checking resistance).
4. Read the results on the display.

**I copied & pasted, so the "W" is actually the symbol for ohms.

 

[Silvertip]

Re: Fuel gauge not working, but all other are true...See 2 pics...

Without a battery you obviously will not have a ground connection anywhere. YES -- the battery must be installed. You do NOT apply power to any circuit on which you intend to measure resistance. It doesn't matter if the gauge wires are disconnected but the pink wire MUST be disconnected at the gauge. Set the meter to read resistance (whatever range allows reading up to 500 ohms or so.). Touch the red lead to the pink wire and the black lead to a KNOWN GOOD GROUND. Yes -- you should read something a little more than 30 or so.

 

[gwizzar]

Re: Fuel gauge not working, but all other are true...See 2 pics...

Without a battery you obviously will not have a ground connection anywhere. YES -- the battery must be installed. You do NOT apply power to any circuit on which you intend to measure resistance. It doesn't matter if the gauge wires are disconnected but the pink wire MUST be disconnected at the gauge. Set the meter to read resistance (whatever range allows reading up to 500 ohms or so.). Touch the red lead to the pink wire and the black lead to a KNOWN GOOD GROUND. Yes -- you should read something a little more than 30 or so.

Thought so... Thank you very much ST!!!

 

[CraigBarnard]

Re: Fuel gauge not working, but all other are true...See 2 pics...

It's actually the reverse. Grounding (well, you are really connecting it to the battery negative side) the sender terminal will peg the gauge to the full side. Do this only long enough to verify the needle does this or you can burn out the gauge.

Right it is the reverse. Thats why i covered my *** by adding "or visa versa" couldnt remember. But either way you will see a change if the guage is actually working. Its a quick and simple check.

 

[gwizzar]

Re: Fuel gauge not working, but all other are true...See 2 pics...

Without a battery you obviously will not have a ground connection anywhere. YES -- the battery must be installed. You do NOT apply power to any circuit on which you intend to measure resistance. It doesn't matter if the gauge wires are disconnected but the pink wire MUST be disconnected at the gauge. Set the meter to read resistance (whatever range allows reading up to 500 ohms or so.). Touch the red lead to the pink wire and the black lead to a KNOWN GOOD GROUND. Yes -- you should read something a little more than 30 or so.

Please refer to the embedded pic... Can I take the pink wire (red arrow) of its terminal, place the red tester post to it while placing the black tester post on the terminal indicated with the green arrow to read resistance as long as the battery negative cables are secured to the NEG post? Thx!

 

[Silvertip]

Re: Fuel gauge not working, but all other are true...See 2 pics...

It's a piece of wire that for all practical purposes IS indeed the same as putting the red test lead on the sender. The only issue with doing that is if the pink wire is broken or disconnected/corroded at the sender, what conclusion can you draw. If your answer is the sender is bad that would be the wrong conclusion. Performing the test at the sender eliminates the pink wire as the problem. So the answer to your question is Yes. But with the conditions just mentioned. If you get a correct resistance reading you then know the wire and the sender is ok. If you get no reading or an incorrect reading you have no choice but to go to the sender to perform the test.

 

[gwizzar]

Re: Fuel gauge not working, but all other are true...See 2 pics...

It's a piece of wire that for all practical purposes IS indeed the same as putting the red test lead on the sender. The only issue with doing that is if the pink wire is broken or disconnected/corroded at the sender, what conclusion can you draw. If your answer is the sender is bad that would be the wrong conclusion. Performing the test at the sender eliminates the pink wire as the problem. So the answer to your question is Yes. But with the conditions just mentioned. If you get a correct resistance reading you then know the wire and the sender is ok. If you get no reading or an incorrect reading you have no choice but to go to the sender to perform the test.

Reading didn't register.. zip, zilch... going to follow the pink sender wire and do what if i can even reach the sender? I don't even know if the sender is accessible. Grrreat.

 

[gwizzar]

Re: Fuel gauge not working, but all other are true...See 2 pics...

Good deal!! Bad sender. New one works perfectly!!! Balls getting to it, but well worth the time and effort. I have it set about 2 inches from the bottom of the tank, so even though the gauge will read "E" I still have some cushion...not that I'll ever let it get below 1/4 tank