How are the fuel gauges wired??

[Beyond A Wake]

I seem to have a continuing issue with fuel gauges. First they did not work after removing and putting batteries back. Turned out to be ground wires not connected at battery. Now they only show tank full and does not move as fuel is consumed. I see the flow rates and total used but not showing on gauge.
So I did reset all when batteries were reconnected and ground wires also connected, so all show full (I have only one tank).
I have a Raymarine Axiom and using the fuel manager on that one to follow usage. The Yamaha display shows the tank as FULL all the time, did not show any tank connected before I connected ground wire.
So perplexed how this set up is wired. I ASSUME the tank sender is connected to the Yamaha gateway? Or harness for display. AND that the Raymarine is getting info through the NEMA 2000 network and the Yamaha gateway. BUT how are the connections to these from Sender/Battery/to??????????

Trying to troubleshoot yet another gremlin and asking for help.

H

 

[DennisG01]

They shouldn't be connected directly to a battery. They are grounded, so yes, connected to the battery in the end, but not direct. It sounds like you have a short between the sender wire and ground. Look at your sender and the pink wire - see if it's shorted to ground at the tank.

 

[Hookup1]

The "fuel gauge" in the Axiom doesn't use the sending unit in the tank. It gets fuel burn info from the computer in the engine via the engine buss.

The Yamaha fuel gauge is getting info (resistance/voltage) from the sending unit inside the tank.

From what I can derive from your post things were working before (last year??) and this is a season startup problem (re-installing batteries). It's something you touched when you took it apart or put it back together. I'll attach some of my notes on sender troubleshooting. It is a simple circuit. Are you sure the sending unit wires are properly connected? Look at Sendtrouble_Page 2 for single tank.

 

[SkunkBoat]

You need to follow the pink wire from the tank and tell us where it is connected on both ends.
"Yamaha display"...is that a CL7(7"screen) or a gauge(which model)?

 

[Hookup1]

Now they only show tank full and does not move as fuel is consumed.

Stupid question: Is the tank full?

 

[seasick]

Pull the access plate over the tank sender area and look for the pink wire that connects to the tab on the sender. Pull it off and turn on the ignition. The fuel gauge should read empty. If it does, now ground the pink wire. The gauge should red full. It both those things happen, your guage and wiring to the hem is OK. If you connect the pink wire back on the sender and the gauge still reads empty then either your tank is empty , the sender is defective, or the sender is not grounded. That could mean that the tank itself if metal isn't grounded. To test run a wire from a good ground like the battery negative terminal and touch it to the sender flange or ground terminal. If the guage now works, you tank ground is bad.

 

[Beyond A Wake]

1. The tank was full when I reset it. Have used 20G since then which does show up as used in Axiom.
2. Yes it must be a connection issue and I start to suspect the 2 wires that were loose from the house battery (impossible to visually see back there) may be that one should be to + while the other to - . I did connect both to - minus ground.
I'm not at boat now so will follow up on this tomorrow pm.
good comments and will trace wires.

 

[Beyond A Wake]

Yamaha is a CL7

 

[wspitler]

Take a look at the CL7 installation instructions. It will show you you can connect up to six tanks to your device. It also shows wire colors to be connected to the level sensors in the tanks. You can troubleshoot those wires by disconnecting them from the CL7 and using an ohmmeter to test your senders.The CL7 must be configured via internal software to match the type and number of senders. See the CL7 manual for details. If you are lucky, it could be as simple as reprogramming your CL7.

 

[Hookup1]

Hey everyone...this is a classic FIT - Failure Induced by Technician. Whatever he did last year screwed it up. It's likely a simple fix IF we don't complicate it and he breaks more stuff. Likely mixed something up when he took the batteries out/back in. I know because I know better but do it all the time!

 

[Beyond A Wake]

I do agree it was all caused by me removing all batteries in order to get to the last one and check for water level and condition of it.
When reconnecting I first ended up with battery 3 minus bus cable getting disconnected upon reinstallation.
2nd when that one was resolved I found out that fuel gauge did not work.
3rd realized two gauge 16? wires were not connected at #4 battery. I connected them to Minus and the fuel gauge appeared and was found for CL7.
4th CL7 shows only FULL after I reset it when it appeared and tank was full.

That is where I am at, so by reasoning one of the wires to #4 is most likely no supposed to be connected to Minus but to Plus. That is what I have to research where they actually come from and then get them right. I do assume they are labeled but cannot get to them with batteries in place so that is a real headache and all because the previous owner/dealer installed cheap unsealed flooded batteries, which I now chose to use for another year As they are Only one year old and tested at 100%.

Thanks for all leads and I am starting with just seeking to correct what I may have displaced.

H

ps
I did have radar and autopilot added to boat and network updated with new switch as well but all was working after that work done by pros.

 

[wspitler]

The fuel tank sender is connected directly to the CL7, not via the Command Link network. Your Axiom may get fuel usage/quantity data via either NMEA2K or J1939. The CL7 had different settings for different sender types, USA , European, etc. I’d check those before tearing things apart.

 

[SkunkBoat]

First off, verify the sender by disconnect at sender and measuring between 33 ohms -240 ohms...thats all been said...

Follow the pink wire to the CL7 connection , whatever that may be. I don't have CL7. I have looked at the manuals and none of them show the physical connection of the fuel tank(s). My guess is they connect to the Command link plus network either through an adapter or a connection to the Yamaha engine cable. IDK.

Only the ground will end up at the battery. You say you fixed that and "RESET". Did you redo the setup after "Reset"?

The manual specifies the Tank setup. It says up to 6 but don't use 5 or 6, whatever that means. You need to varify your tank is connected to 1.
Check the settings of the CL7 for the sending unit type and sender number.




Its possible that the tank sender goes to a NMEA2k fuel sender adapter and connects through N2k. But I have never heard anyone on this site describe eir connection

 

[Beyond A Wake]

Update;
took off ground at battery (2 wires tied together) for fuel And cleaned and put back with checked good contact.
CL7 shows full or alternatively just lines. Tank is recognized and shows 88%, so as correct Ab 20G used from full.
My assumption now is that the calibration is such that it shows full for a while until reacting to some fuel used. On Raymarine I can see used Gallons and hours etc.
so I'm going to once more go through the procedure of setting tank as full after fill up and reset all Raymarine meters check that tank volume is correct and same on both CL7 and Raymarine. It was 260 while tank holds 293G, I guess it is a safety margin of 10% inserted or maybe tank holds 293 but only 260 can be used????
Anyway will let you know how it continues.

H

 

[seasick]

Depending on things like the tank angle at rest, the shape of the tank and the clearance between the bottom of the sender and the tank floor, the levels sensed wont match perfectly to the actual quantity of fuel in the tank.
The worst case is where the fuel sender sits lower than the actual fuel pickup tube. It's rare but can happen. In that case, the sender may think there is some gas left but the pickup is higher than the level.
One should keep in mind that the fuel level may be a best guess
On the display the remaining fuel reading may be based on the initial calibration less the fuel used ( based on engine data, not sender reading, so if you calibration was off, so will your remaining fuel estimate.