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  #1  
Old 01-05-2010, 09:18 PM
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Overfilled! Amt of fuel through return line?

I run WVO in my 84 300SD and recently set up a fuel cell in the trunk
to start & stop the car on thinner fuel. I put in a 5-9 psi fuel pump to
help bring the fuel up front. I noticed my 2nd tank going down rather
quickly and figured it was getting returned to the original tank.

Well, tonight I noticed a fuel leak under the car and realized
it was because the main tank had overfilled! I had recently
topped off the main tank with WVO.

My question is: how much of the fuel gets returned to the tank
during normal operation?

Thanks,
Jeff

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  #2  
Old 01-05-2010, 11:33 PM
compress ignite's Avatar
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This is Kitchen "Fluid Transfer"

I "Think" I remember you actually use about 1/10 of the fuel that's Pushed Through the Hard Metal Injection lines to the Injectors.
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  #3  
Old 01-05-2010, 11:48 PM
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The amount depends on how good your lift pump & filters are. There is no set amount. If you have a booster pump, you will get a lot more. If you have 2 tanks & run on 1 with the return to the other you will empty one into the other. If everything is perfect, and standard, I believe compress is about right. If you want to find out how much yours is returning, disconnect the return & time it into a bottle.
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  #4  
Old 01-06-2010, 08:41 AM
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How do you switch tanks?
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  #5  
Old 01-06-2010, 09:48 AM
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"How do you switch tanks?"

I use a solenoid I bought from Greasecar.
I bought an RCI fuel cell off ebay and installed
a toggle switch and fuel level gauge where the ash tray used to be.

There is absolutely no change in performance when
I switch between the two.

Jeff
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  #6  
Old 01-06-2010, 09:58 AM
rrgrassi's Avatar
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Did you also incorporate a return to each tank, so that WVO will return to the WVO tank and diesel will return to the fuel cell?
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  #7  
Old 01-06-2010, 11:01 AM
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I have the same valves in my 240. Make sure the ground wire is attached and has good a good connection for both valves, and that they are working. You should be able to hear and feel is switch when you give it 12 volts, you might have gotten a bad valve. I once left the ground for the supply valve off when doing some work, and it filled my veggie tank when I switched to veggie because is was still pulling from the diesel tank but returning to the veggie tank.

Is it plumbed correctly? The single port on the top of the valve is where the return fuel should come into the valve, then the normally open side should be the diesel and the normally closed side should be the VO.
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  #8  
Old 01-06-2010, 11:09 AM
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Quote:
Originally Posted by compress ignite View Post
I "Think" I remember you actually use about 1/10 of the fuel that's Pushed Through the Hard Metal Injection lines to the Injectors.
if your injectors leak that much its long past time for new ones!!!
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  #9  
Old 01-06-2010, 04:17 PM
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Yes, the solenoid is working correctly.
I do not have a return line going back to the
newly installed tank. I intentionally did it that way
so that the WVO could be thinned out a bit by the
diesel/biodiesel fuel.

I just didn't know it would return so much!

I live in Northern California and I don't need to run
the thinner fuel for very long before I switch to the WVO.

My soulution now will be to simply keep the main tank only 3/4 full
when I am running both tanks. I have run WVO on a single tank
for the last two years with no problems. In the past, I simply
added diesel/biodiesel to the WVO in the wintertime to thin out the fuel.

Jeff
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  #10  
Old 01-06-2010, 05:15 PM
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I don't think that will work. You'll pump a quarter tank of fuel in less than an hour thru the return line if my experience is any indication.
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  #11  
Old 01-06-2010, 05:54 PM
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Quote:
Originally Posted by kerry View Post
I don't think that will work. You'll pump a quarter tank of fuel in less than an hour thru the return line if my experience is any indication.
I agree you're gonna drain your diesel tank really quick. The engine is supplied with much more fuel than it needs. I've hooked up a quart ATF bottle to the supply and left the return stock and it sucked up all the ATF in just a few minutes. You either need to loop the return, which causes air issues, or put in a return line to the veg tank.
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  #12  
Old 01-06-2010, 07:14 PM
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That was my original question--how much fuel gets returned?
Seems like a fair amount.
I only need to have the engine running for 5-10 min before I switch
over, but there might be too much fuel getting returned for even that
small amount of time.

I'll see how it goes this week and if I'm losing too much fuel out of that
start-up tank, I'll just plumb in a return line.

Too bad though, for a second there, I'd thought I'd discovered the
Eternal Fountain of Fuel!!

Jeff
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  #13  
Old 01-06-2010, 07:25 PM
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Lots of people are probably thinking it, so I'll just write it. It's not worth plumbing in the extra return line because since you're running on WVO, the engine won't last long enough to make it worthwhile.
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  #14  
Old 01-06-2010, 07:25 PM
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Add another return line. Or be nice to your engine and stop running WVO.
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  #15  
Old 01-08-2010, 10:55 AM
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Quote:
Originally Posted by kerry View Post
Lots of people are probably thinking it, so I'll just write it. It's not worth plumbing in the extra return line because since you're running on WVO, the engine won't last long enough to make it worthwhile.
I truly do appreciate your concern for my engine, but, you see, after doing a lot of homework I specifically bought this car to run off of WVO.

Before converting over with a kit from GreaseKings, I took a compression
test of the engine--all of the cylinders had excellent compression.
Next time I take the injectors out, I'll do another compression test and
this forum will be the first to get the results.

I'm a complete agnostic as to whether on not the WVO will kill my IP and engine.
I can only speak from my experience. I have run WVO through this car for two years
and have had absolutely no problems whatsoever.
It's my daily driver and I love the car.

If there was a serious problem with the process you'd probably see a
Sticky on this forum labeled "WVO killed my IP and engine!" instead of
a WVO Biodiesel SVO Sticky.

Absolutely happy WVOer,
Jeff

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