Trouble shooting gas gauge

[banhtrang]

Hello,

I took my boat out for the first time...Everything works but the gas gauge, would you experts show me how to trouble shoot this please

thank you

 

[Bt Doctur]

Re: Trouble shooting gas gauge

12v at the gauge itself, ground the sender lead, gauge goes full scale
At the tank sender, using a remote ground wire from the battery, ground the pink lead, gauge should go full scale
Test tank ground by using the remote ground wire,
Remove sender and test manually

 

[Silvertip]

Re: Trouble shooting gas gauge

Ground the gauge BRIEFLY or you can toast it. If you know how to use an ohm meter then disconnect the pink wire on the SEND (S) terminal on the gauge. Measure resistance from the pink wire to ground. If you have an idea how much fuel is in the tank, the ohm meter should read 240 ohms empty, 109 ohms 1/2 full, or 33 ohms full. Readings may obviously vary depening on the amount of fuel but you are after an approximate number here. If you get no reading (open circuit) them make the same test at the fuel sender (threaded post to ground). If you still have no reading the sender is toast. If the numbers now correspond with those just given, the sender wire is open. Make sure the metal shell (flange) of the sender has a good ground. If that is not present the system will not work. Here is a diagarm of the system -- again!

 

[banhtrang]

Re: Trouble shooting gas gauge

Thank you all for your superb support! I will do some test using your instructions

 

[banhtrang]

Re: Trouble shooting gas gauge

Hello,
Attach is the picture of the fuel gauge, I dont know why the black wire and the pink appear to be connected. Would you tell me if this is correct?

thanks

 

[banhtrang]

Re: Trouble shooting gas gauge

This is the picture of the back of the gas gauge, please help me identify them.

I Assume, the "A" is the connection to the sender "Pink"
the "C" is the common from the negative the Blue "B" and "D" is power to the led?

thank you

 

[Silvertip]

Re: Trouble shooting gas gauge

Your gauge doesn't work right because the only wire thaet should be attached to the threaded sender post is the pink wire. The flange with the screws that secure the sender to the tank is at ground so the sender is grounded. Remove that wire and connect the flange end of the wire to ground, not the sender terminal. The gauge terminals are normally marked with a + sign, - sign or ground symbol and the sender terminal is marked with an "S". Since the wiring on the sender is wrong, do not assume it is correct on the gauge.

 

[NYBo]

Re: Trouble shooting gas gauge

It's hard to tell where that black wire is connected near the sending unit (first pic). Is it connected to the Phillips screw opposite the one that's showing? If so, it is connected to the proper spot.

 

[Silvertip]

Re: Trouble shooting gas gauge

Tjere should not be a black (ground) wire connected to the same terminal as the pink wire. If the upper end of that black wire is NOT connected to the same point as the pink wire, then it is likely ok. It would appear that the small phillips screw at the 6 o-clock position should be the sender ground. All of this is really no real value unless you get an ohm meter and start doing some testing.

 

[NYBo]

Re: Trouble shooting gas gauge

I think there is probably another Phillips screw at 12 o'clock.

 

[banhtrang]

Re: Trouble shooting gas gauge

Here's another angle. I think they are very close but not touch I am not sure, do you think it's safe to do the continuity test on those two posts? the black wire for sure is looped down to the base of the sender

 

[banhtrang]

Re: Trouble shooting gas gauge

I check the gauge and it goes full scale so my gauge is good. I did the the resistant test, but get fluctuated result. Next step I will unplug all the connection at the sender and re connect to see if it's just bad connections. For now i have to stop and bring the boat to the storage or I will get a letter from HOA

 

[Silvertip]

Re: Trouble shooting gas gauge

When doing resistance checks you need to eliminate any other circuitry from the one you are trying to measure. So yes, disconnect the pink and black wire from the sender. Then measure from the terminal the pink wire is connected to and a "known" good ground. The bottom end of the black wire would be a logical place.