Diesel fuel electronic monitor

[leehaefele]

I am considering buying an electronic fuel use monitor. Looking for recommendations. I have a Nauticat 33 with Ford Lehman 90 engine and 2) 80 gallon side tanks. The dash mount guages were replaced by PO with on tank float guages which are now broken. I would like to know instant fuel use to optimize economy. Another problem I have is that there is no selector valve on the return lines to the tanks, just a "T". The returned fuel then returns to the lower tank, which if I am not careful, overflows.

[delmarrey]

Just a thought that might work.
If your return fittings on each tank had a tube that extended down to within an inch or so from the bottom. Then when the fuel got to a certain level in one tank, that would create back pressure forcing the fuel thru the T into the other tank, considering the tanks are at the same level and the T is spaced half way between each tank with equally sized tubes and hose after the T.

If under sail while motoring, I'm not sure it would work due to heeling over may cause a false pressure. But motoring in a rough sea the pressure would be alternating back and forth averaging it out kind of like a siphon.

Whatca think?

[GordMay]

FloScan is the leader in ultrasonic fuel monitoring systems. Costing between $500 & $1,000, they are NOT cheap!
(url) www.floscan.com /(/url)

There are others ... just can't think of them ... help?

Tempo makes a manual diverter valve (#140050 - about $25), which would allow selection of which tank the fuel returns to.

I presume, you don't have a fuel transfer pump? Jabsco makes several models of Vane Pumps (45710 Series & SPO-60 series @ $150 - $300), suitable for fuel transfer.

Hope this helps.
Gord

[Pblais]

I have twin 30 gallon takns and near the tank selector I have a T junction for the retrun lines. Mine has a valve so you can divert the return to either tank. So long as you return to the same tank no probnlme but it can come in handy to use the valve as a fuel transfer pump if you want tbalance the load. The T valve should be easy enough to install if you just cut out the T junction and replace it. You just have to be sure to switch both the tank selector and the return valve at the same time. That should be an easy project to install.

I have float style level indicatiors and I can't say I like them much. They tend to read totally full for a long time then quickly drop. When they say empty you are sucking air. They work but it has taken some time getting used to them.

[DeepFrz]

This is one maker of capacative sender units. They should be quite reliable as there are no moving parts except needle on the meter. Of course tank shape and heeling will change the readings, as with any tank probe unit but they are a lot cheaper than the Flo-Scan units.

www.centroidproducts.com

[GordMay]

I don’t know what I was thinking, when I wrote my previous response. I should have specified that:
Fuel should only be returned to the tank from whence it came. This is very important!

I would never use “cross-returns” in lieu of a dedicated fuel transfer system. The potential for operator error is too great.

[Talbot]

Navman plotters have the facility for adding fuel flow metering for both diesel and petrol engines. Thus for the price of just the fuel meter, you can also have a darn good c-map plotter

Their latest version of the 5600 (IIRC 5605) will take the C-Map Max ctg

I have the slightly smaller 5500 and it is a nice piece of kit.

[Alan Wheeler]

The Navman fuel measuring system was developed with major testing being carried out by a very knowledgable and highly respected NZ Marine Deisel engineer. His name is spoken in "hushed tones" within the NZ boating community. Anyway's, Len is the sort of guy that if you ahve a lemon, will tell you in plain and simple terms, you have a Lemon. He has had many systems given him for trial over the years, but all have failed miserably. The issue is in the complexity of the fact the the supply fuel and the return fuel has to be measured and summed to get the amount used. But with Deisel, the hot return fuel has expanded considerably and it mucks up an accurate measurment in most systems. This means that to get a very accurate measuring device, equates to a lot of dollars and a very complex system. Navman solved that issue and have a highly accurate device available at an affordable price to most.

[Talbot]

When I bought my plotter, you could only get the kit for petrol engines, and I didnt bother. My fuel tank is a white plastic which is easy to view the amount of fuel in the tank, so its not a great additional facility for me. (thus I havent bothered).

[Saildude]

On this Navman thread, I've downloaded the manual for the Diesel 3200 model and it looks like it will not support a single engine twin tank configuration. Can anyone who has this system confirm that?

[Alan Wheeler]

Not sure what you mean by not supporting a "twin tank" arrangment. The fuel monitor goes in the main line, which there will (or should) be one of. Can you describe further so as I can understand the problem??

[Saildude]

I have a single engine and two fuel tanks. Each tank has a separate set of lines to the tanks, each with its own valve. In other words I have four valves - one supply and one return for each tank. I suppose one could put the sensors upstream from the valves, but then you wouldn't know how much you have in each tank.

Interstingly, I just got an email from the folks at BNT Marine stating that Navman does not offer a diesel fuel solution. That's interesting. So what is the "Diesel 3200" all about then?

[Alan Wheeler]

Firstly, you need to tell BNT to go read their info more thoroughly. Navman do indeed do a Diesel unit.

OK your issue is simple to solve with just a little simple plumbing. First of all, the return line does not actually need to go all the way back to a tank. This is a common way that systems are plumbed, but is totaly unnecessary. The return line can go back into the main line anywhere. Usually the best and simplest place is to return it back into the fuel filter.
But in the case of fitting the fuel monitor, there will be a sensor on the supply and return line to monitor the supply and the return fuel. The difference is what is calculated.
I presume that at some point, the supply line from each tank comes together at a Tee to make one main line, correct?? So the return needs to go into the supply line between the tee and the fuel supply sensor, with the return sensor in the return line of course. Don't worry about going all the way back to a tank with a return. It just complicates everything.
Did I do OK at making that understandable enough?? Please ask if I didn't.

[Saildude]

I agree that putting the sensor in after the tee is a solution, but how do I tell how much I have in each tank?

[Weyalan]

Originally Posted by leehaefele

Another problem I have is that there is no selector valve on the return lines to the tanks, just a "T". The returned fuel then returns to the lower tank, which if I am not careful, overflows.

An "L" 3-port ball valve will cost a few dollars. Fit it at the "T" in your return lines and you can then select which tank your fuel returns to.