Remaining Fuel Always Zero


Furuno Fan
On my boat, the "%Full" display of fuel level shown by the TZT14s is correct but "Fuel Remaining" is always zero. An actual zero is displayed, not a dash, so the TZT14 thinks it is getting data. The Cummins/Mercury Vesselview display of %Full and Fuel Remaining is correct. My understanding of the setup is that the VesselView receives fuel level from the tanks sensors and forwards it to the TZT14's via a Cummins/Mercury "NMEA2000 Gateway". The fact that powering off the Vesselview causes the zero on the TZT14s to change to a dash seems to confirm that.

There is no way I could find to specify fuel tank size in the TZT14 setup, so the only way I can think of for %Full to be correct and for "Fuel Remaining" to be zero is for there to be separate NMEA sentences for each of those items (or perhaps just for tank size). It seems strange that one should pass through the interface correctly and the other not when they are really different display formats for the same underlying information. RPM, fuel flow and rudder angle are displayed correctly by the TZT14's, so quite a bit of data is getting through correctly.

A problem that may be related to the TZT14's thinking that Fuel Remaining is zero is that I get a "Fuel Capacity Alarm For Active Route" warning popup whenever I navigate to a point. I can't find that alarm in the list of alarms. I would like to disable it at least until the Fuel Remaining data gets across the interface correctly.

I realize that the Cummins/Mercury NMEA2000 Gateway is a likely suspect, and will ask them the same questions, but hopefully someone here has already solved the problem.

Have you setup your Fuel tanks and Tank Calculations under MENU - INITIAL SETUP?
What does your tank level display (Para 10.3.3) show? (can you post a screen capture?)
How about the engine info setup? Is that data in the setup also been configured?
I've attached a photo of the Tank level display (10.3.3). It shows the tanks as 64% full but zero gallons remaining. Vesselview shows 317 gallons remaining which is close to 64%.
The fuel setup page has number of tanks (2), tank nicknames (Port & Starboard) and UseForRangeCalculations (ON). The engine setup page has number of engines and "red zones" for rpm, temp, oil pressure, etc. I couldn't find any place to specify tank capacity.
Tank capacity is a setup parameter for the VesselView which is how it is able to display gallons remaining when the tank sensors report only level. The tank sensors are connected directly to the Vesselview system and don't put their information on a bus, so Vesselview probably forwards tank level information to the TZT14's via NMEA2000.

Other information such as engine rpm, temp, fuel flow and rudder angle are probably forwarded in the same way and all those are displayed correctly.
It appears that you are missing PGN # 127489 to the bus.
The Furuno TZtouch uses PGN 127505 to get your fluid type/level and tank capacity and you seem to have that working. What isn't working is the fuel calculations which requires PGN 127489. We use the Total Fuel (Flow) Rate by using a simple sum of the fuel flow of the engines. I think if you can get that PGN on the network with the TZtouch, it should work for you.
I should have mentioned that those photos were taken with the engines not running. When they are running, the TZT14 displays the correct fuel rate as well as RPM, temp, oil pressure, etc. PGN 127489 seems to be passed correctly.

PGN 127505 contains level and capacity. It does not explicitly contain remaining gallons. Does the TZT14 compute remaining gallons from level and capacity or does it require an additional PGN such as 127496 (Trip Parameters) which contains fuel remaining?

Perhaps the Vesselview is not passing PGN 127496.
127496 is not used by the TZtouch, only the two sentences I mentioned.
It uses these to determine its own fuel remaining and doesn't rely on another device to provide 127496. This way customers with just tank sensors and engine info can work without additional equipment. I am glad to hear your display does indeed work when your engines are running.
Just to be clear, "remaining fuel" is still displayed as zero by the TZT14 even when the engines are running.

If, as you say, the TZT14 uses only PGN 127505 to display "remaining fuel", it must compute it from tank level and tank capacity. Since tank level is displayed correctly by the TZT14, and since both tank level and tank capacity are displayed correctly by the VesselView, tank capacity information must be getting lost between the time it is sent by the VesselView and the time it is received by the TZT14. Note: the VesselView receives the raw tank level information from the tank level sensors and gets tank capacity from a user-supplied setup parameter.

It seems unlikely that a bus error would be corrupting the information in exactly the same way every time. On the other hand, if the VesselView is simply creating a PGN 127505 with correct level information but with capacity always zero, it seems unlikely that someone else wouldn't have already discovered the problem.
To clear this in my head; you have verified you have PGN 127505 from your VesselView and verified you have PGN 127489 from your engines?
The TZT14 correctly displays fuel rate, rpm, engine temp, oil pressure, etc. so PGN 127489 must be getting passed correctly. The TZT14 is able to display tank level from all 4 tank sensors (including water and waste), so at least the FluidLevel part of 127505 is getting passed correctly.

In my setup, the tank sensors provide only FluidLevel information and are connected directly to the VesselView system. TankCapacity for each tank is specified manually during VesselView setup. A Mercury "NMEA2000 Gateway" converts that internal VesselView information to NMEA2000 PGNs.

The most simple explanation is that the gateway creates a PGN 127505 with correct TankLevel but with TankCapacity=0. If that were true, surely others would have encountered this problem, even with other chartplotters, but my web research has turned up nothing.

I guess I'll have to get someone with a NMEA2000 sniffer to look at it.
Look at my post a couple down for "Engine Parameters". Perhaps you are experiencing a similar thing. I couldn't get PGN 127489 to display oil pressure on the TZT until I passed oil temp to the Furuno. It seems like there is an issue somewhere with this PGN and the TZT and you may need to pass some additional information even though you are not trying to display that information on the TZT. This link has some good detail on the PGN:
I seen the posting and agree that there might be something worth getting Japan to look closer at. Based on your case, it almost sounds like a PGN field is being left blank instead of having a proper place holder. I will pass your info and Noland's offer up the chain.

You are correct, that if the Vesselview is keeping the tank capacity for it's own use and not passing it on via the PGN it could explain the problem. I am not too surprise that other users haven't chimed in because I don't think that many customers take full advantage of all the features offered. It might also be something on the Furuno side of things. I will pass the info forward and maybe others will have more to add.

I thought the same thing you did but their claim is they haven't seen this with other displays so I thought I would pass it on in case it wasn't just a coincidence.

Sheakx, I couldn't find a way to enable additional PGNs in the VesselView NMEA2000 gateway. The manual states that both TankLevel and TankCapacity from PGN 127505 are passed. The manual for the VesselView itself doesn't say anything about enabling output information. The TZT14 doesn't seem to have a way to enable or disable input PGNs. It must use whatever is available from the bus. It does allow particular tanks to be excluded from fuel calculations.

I haven't been able to get much information from Cummins/Vesselview on exactly what is exported.

It looks like a NMEA2000 sniffer is the next step. Does anyone have experience with these?

In my case, I didn't need to send additional PGN's. My case was for PGN 127489 only. I needed to send the value for Oil Temp in order for the TZT to see the value for Oil Pressure. It did recognize Engine Temp without sending the Oil Temp Value. If you can control what is sent for PGN 127489, I would try sending everything possible to see if that helps. The reason my case seemed strange to me is for PGN 127489, Oil Pressure is field 2, Oil Temp is field 3, and Engine Temp is field 4.
the Mercury gateway documentation lists the TankLevel and TankCapacity fields of PGN 127505 separately, but I couldn't find any way to control them separately. I've asked Mercury and Cummins about this but haven't gotten a reply yet.

I've been studying the TZT14 setup screens trying to figure out how information is transferred from the VesselView to the TZT14's. The "Data Source" screen shows "Gateway CAN-P Multi" as the source of "Rudder Angle" which is displayed correctly by the TZT14's. On the other hand, engine RPM, temp, fuel flow and TankLevel are also displayed correctly, but they do not show up in "Data Sources" or "Sensors". The "Sensors" screen shows a single "CAN-P Multi". It seems unlikely that Rudder Angle would have a separate line while engine information, fuel flow rate and tank level would not.

The "Sensors" screen shows 3 different lines for "IF-NMEA2K2". The first two say version=1.03:01.01 and the third says 1.04:01.01. My understanding is that the only purpose of the IF- NMEA2K2 in my setup is to convert heading information from the PG-500 which uses NMEA0183 to the NMA2000 used by the TZT14's. Could the multiple instances of the IF-NMEA2K2 be confusing things?
It sounds like you have three IFNMEA2k2 converters. Two with 1.03 software and one with 1.04 software. They should all be given different instance numbers so they don't have communication problems. You can assign the instance using your TZT. Japan as been asked to read these threads and look into the engine data sentences. I will let you know if I hear anything back on our side of things.
You are right. There are three physical IF-NMEA2K2's in my boat. One for the heading sensor, one to send GPS position info to the VHF and one that connects to the NMEA0183 port of the Mercury VesselView. I gave all three of them different instance IDs but that didn't help. I also tried disconnecting the one that goes to the VesselView since there is also a Mercury NMEA2000 gateway between the NMEA2000 bus and the VesselView. Having 2 converters doing essentially the same thing seemed like a possibility for trouble but disconnecting one didn't solve the problem either.
I put an ActiSense sniffer on my NMEA 2000 bus. It showed that the PGN 127505 has tank capacity = zero. The VesselView could be setting it to zero instead of using the information it got during setup or else the SmartCraft gateway is not converting it correctly.

I wish the TZT14 had the option to specify tank capacity to handle the case where the producer of PGN 127505 did not insert the correct tank capacity.


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Thanks for the additional information. Japan has been looking into this so I will pass your additional findings. Overall, under current programming; the TZT requires PGN 127505 to have the data for the feature to work. I don't think they have any plans to allow tank capacity to be manually input.
It would be a very good idea to revise the software so that the fuel level could be manually input instead of taking it off a tank level sensor. This is how Garmin and others handle the fuel remaining and fuel level data fields and for several very good reasons:

-- Tank sensors are notoriously inaccurate in operation on the water because the running attitude of the boat is changing constantly and the fuel is sloshing around even with a baffled tank;

-- Many boats (such as mine!) have a main tank and auxiliary tanks from which fuel can be transferred to the main tank but not supplied directly to the engines, which means the range would be overstated if you have three tank sensors until you actually transfer the fuel;

-- The fuel rate date is extremely precise from electronically controlled engines, which makes 0.1/gallon accuracy possible if you can input fuel directly instead of using a tank level sender.

This is a very useful feature that should be available on the TZT displays. A dumb little Garmin GMI-20 instrument can do this, why not a TZT14 that costs 15X as much? In fact, I went out and bought a GMI-20 just to have the fuel functions because I make very long runs out to the canyons to fish and need to know precisely how much fuel I have remaining. Fuel economy can drop a lot in rough seas and no one wants to come home on fumes.