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Producing my own diesel

August 08, 2011, 02:56:45 pm

Last week, Jennifer and I left for a trip to our cabin in Telluride.  Since we now have three dogs, I thought it would be nice to take the motorhome so that we would all have more room.  When we left our house the fuel tank read 3/4 full.  To my surprise, when we arrived in Telluride, some 420 miles later, the full tank read full.    One of two things is possible.  1) I have some type of diesel fuel production facility on-board that I do not know about.  or  2) I need a new fuel sending rod.  I'm leaning towards number two.

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Re: Producing my own diesel

Reply #1 – August 08, 2011, 03:35:08 pm

Brian,
I'd lean to #2 if I were you. 
You might want to check the following thread:  Fuel gauge accuracy?
Make sure you get the new DIGITAL sender.  Should be much more reliable than the old syle.  I'm still carrying mine as a spare, so I'm still not sure.
Neal
 
 
 
 
 
 

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Re: Producing my own diesel

Reply #2 – August 08, 2011, 04:09:47 pm

EZ to make a measure stick/wire. Just dip the tank and measure and you have a super accurate reading (assuming the rig is level). You can do the math (L x W x H remembering there are 231 cubic inches in a gallon) or fill five gallons and mark the stick and then repeat it until full. Can also put an adhesive tape on the outside of the tank with the gallons printed on it to put the stick against after you stick it. Never a question then. You can also use this to calibrate your dash gauge so, for example, when you reach 1/4 tank you will have X gallons left.

Either way, you can figure the gallons per vertical inch on the outside (and inside) of the tank.

Have had an algae buildup on the sending unit give bad readings several times on diesel cars. If you pull the sender and it has black stuff on it...

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Re: Producing my own diesel

Reply #3 – August 08, 2011, 05:24:27 pm

Fuel measuring is a needed subject, why I use and trust the VMSpc setup, have used it enough to trust it.  Both the fuel used, fuel remaining and fuel mileage have always been closer than I can figure.  But as in all important issues, one needs to keep your head clear and scan what is going on.  It is easy to forget important things, so why I go with what works for me.
My fuel gauge started acting up, showing half a tank when full, as it burns off some, the gauge starts to become more accurate. But like most I run in the upper half generally.  Most have ever needed to fill was 108 gal, the VMSpc claimed I used 106 gal, I figure the 2 gal difference was running the generator a few hours.

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Re: Producing my own diesel

Reply #4 – August 09, 2011, 03:07:08 pm

Another advantage of using the stick method is you can tell if and how much water you have in the bottom of the tank.  It's done regularly when sticking bulk tanks.  Get some water finder paste Kolor-Kut for instance.  Put it on the bottom couple of inches of the stick.  It changes color in the presence of water.  Best if done with tank level and fuel well settled.

Keith

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Re: Producing my own diesel

Reply #5 – August 09, 2011, 03:45:27 pm

If I were to check for water in bottom of fuel tank, I would lean the coach to one side slightly, let sit for awhile, then do the paste on stick test on low side.  Have never had any sign of water in the fuel tank YET. 
We do carry the paste on the service trucks for checking for water in generator tanks, mainly the buried tanks, as they seem to have more of a problem, but both base and day tanks can also get a little water.
Good point Keith.

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Re: Producing my own diesel

Reply #6 – August 09, 2011, 05:18:10 pm

Good word YET. I can remember checking my aircraft fuel tanks with the little plastic tester. Most of the time it showed no water but occasionally it would take a couple of samples to get rid of all the water. Suspect it came from partially full trucks with water condensing inside but could have come from the ground tanks since we had high humidity next to the ocean.

Checking the drain on the plastic bowl at the bottom of the primary fuel filter on a regular basis is a good idea. Any water there means water in the tank and water in the tank with diesel is a potential source of algae. Any black in the bowl means algae in the main tank.

We blew off the tip of an injector in an almost new 8V-71. Factory guy said water had turned to steam blowing off the tip. We emptied both filters into a bowl but no water. The factory rep convinced our mechanic it was water that did it and sold him on it. Naturally, that meant that the FD had to pay for the service call not Detroit Diesel.

Good idea about leaning the rig before trying to sample.

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Reply #7 – August 09, 2011, 11:58:16 pm

I am constantly amazed at you guys around here!!  The idea that you know what Kolor-Kut is and what it is used for.

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Reply #8 – August 15, 2011, 03:25:50 pm

I made a foot long aluminum flat bar with gallon markings and a heavy string. Drop it in the tank and let it go down until I hear it hit the bottom. Provides very accurate fuel available info for less then quarter tank. With low fuel, I dip the tank to be sure how much fuel is left.

I cleaned the three contacts and wire ends attached to the fuel gauge sender.  My fuel gauge has been consistent ever since.  Others on this forum have reported eratic fuel gauge even after cleaning these wires.

I removed the fuel gauge sender and found it was very clean.

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Re: Producing my own diesel

Reply #9 – August 15, 2011, 04:05:26 pm

My bet is that the erratic performance is due to a bad ground if the contact points are clean.

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