WVO fuel issue

[wal1809]

Alright fella and fello busnuts I have a problem I am trying to work out.  It deals with my waste veg oil fuel system.  Hold on before you stop reading.  Some of yall on here know fuel systems front and backwards so your thoughts could solve the problem, whether yall believe in WVO as a fuel or not.

Here is the problem.  I have replicated the original fuel system in the bus.  I am running 50% bio diesel and 50% store bought diesel in the main tank (no problems).  In the WVO tank I am running the same fuel 50%/50% so I know it is not a fuel issue.  I have installed two 3 way valves.  The first has main tank fuel to one port and the other has wvo tank fuel coming to it.  When the valve is turned off the motor is running off of the main tank.  When the valve is activated it is running off of WVO tank (Remember same fuel in both tanks for now).

I can take off and run like normal when on the main tank.  When I switch I feel a power loss.  Te bus will get to 60 mph max and takes a long time to get there.  When I switch back to the main tank it clears up in about 5 seconds and all is back to normal.

There are 4 components between the wvo tank and the motor which are 2 heat exchangers, 1 spin on filter and the 3 way valve. The fuel line is larger than the original fuel line.  I don't believe that is a factor.  The filter is brand new with only about 2 or 3 gallons of fuel through it.

I bypassed 1 heat exchanger and it is still doing it.  I don't believe the other heat exchanger is the problem.  When it was out I blew air through it and it was an easier flow than the other heat exchanger.

One person I spoke with believes it could be an air bubble issue.  I can't get my head around that.  When I put this together I used yellow tape and I cranked the bs out of the fittings paying particular attention to getting that part right.  I have ordered a vacuum gauge but it is not here yet.  I intend to put a gauge on it after each component to see if on is particularly higher than any of the rest.

Any thoughts?

[Van]

Return pressure? maybe blocked vent ? I'm curious. Good luck.

  Van

[wal1809]

Hold on there van!! This did not cross my mind.  Talk to me about return pressure. 

Where is the check valve located on a 6v92? 

I tapped into the return line where two lines were connected end to end by a compression fitting and the line was headed back to the main tank. 

The fitting was on the return fuel line to the left side of the motor.  I hope I didn't pull a stupid.  Is there 1 or 2 return fuel lines?

I used the same fuel line for return that I did for the the main fuel line.  I just assumed I was on the downwind side of the check valve.  If I have missed the check valve then the return fuel to the WVO tank will be wide open and no pressure building up.

Is the check valve on top of the motor right in front of the blower where the fuel lines are connected to.  I assumed it was in there as I can see the original return fuel line is not interrupted as far back in there as I can see.

Tell me some more while I go poke my head under there.

[jackhartjr]

Rut Row!
A friend bought a sailboat...did not trust that the diesel fuel was good...so he moved the fuel line to a 5 gallon can and took off in Charleston Harbor.  Got back to the dock and wondered why there was a large fuel sheen around the boat.  I asked him if he had run the fuel return line to the 5 gallon tank too?  He asked if that was important.  (He had been filling up the fuel tank on the boat!)
I say all that to ask this question; When you switch fuel tanks does that also switch the return lines to the tank you are drawing from?
Jack

[wal1809]

Yes there are two 3 way valves.  1 valve selects fuel from wither tank and the second valve allows it to go to either the main tank or the WVO tank.  It is up to the driver to decide.  In other words I can leave the second valve on if I want to send regular diesel to the WVO tank to aid in diluting the fuel, purge that tank of WVO and up the esters of the WVO.

I used the original fuel return line to the valve and added new where it was needed to complete hooking up the system.

[Len Silva]

Is the second tank properly vented?  Try leaving the fill cap loose if there is any question about that.

Try leaving the return line switched to the main tank while you supply from the second tank to eliminate the return circuit. (Make sure you have enough room in the main tank for the return fuel).

Other than that, I can only see a suction leak or restriction in the second supply line.

[wal1809]

I have tried the fuel return in both directions.  I tried main tank to WVO tank and no problems. 

The problem only happens when I switch on the WVO tank fuel to motor.

It is going to be a pain in the hind end but I am going to get a 6 foot piece of fuel line and go straight from the tank to the motor and start back tracking behind every component until I find it.

I got a feeling it is the filter.  I bought a 1 inch port fuel spin on fuel filter housing from tractor supply.  I figured it would be ok as I would be replacing the cheap spin on filters quite often.  The 1 inch ports are necked down to 1/2 hose barb fittings.  I am wondering if there is not a bubble of air trapped in the top of that housing.

[NeoplanAN440]

you will be searching for ever , without a vacuum gauge and fuel pressure gauge !!!

first the orrifice for the return from the engine , should be after the t where both return lines from l and r head come together !!!   a fuel pressure gauge will show you if its there, or if you maybe have it only when return valve is switched to diesel. without the orifice , you will have almost no fuel pressure , and related to it no power.

on the other hand , the vacuum gauge will show if the issue is maybe  the valve size (restricted ) or maybe a bad flowing filter.  some diesel filter will not work well with wvo. and flow horrible. even with my large heated racor fh 500 i see some restriction.
also i think you mentioned you use the omar valves. i think from how the seals are working, that they wont flow the same on both ports!!!


just my cents

[wal1809]

Winner winner chicken dinner Neoplan!  I went out and hooked a 6 foot piece of fuel line straight from the tank to the valve, bypassing all of the components with the exception of the valve.  Same thing happened.  I did not run it long as there was no filter.  I now suspect the the 3 way valve has 2 different flow rates.  In the off (diesel position) the flow rate has to be higher.  The restriction is right there in the valve.

I will order the others and use these valves for my Excursion when I gain the juevos to tackle that project.

NEoplan what is you thoughts on the sv200 valves?

[Van]

Sounds like you got a handle on it Wayne, Lol I just threw that out there. My check valve( 89-15) is where the line comes in thru the bulk head.

[norules]

can't find info on SV200

can they handle a 6v92ta spill rate (return fuel) of 62 GPH at 50-70 psi  (full load/max rpms for a 6v92ta)

[luvrbus]

Sure glad you got it solved Wayne I was going to return your call Sun and tell you to switch to McDonalds   


good luck

[robertglines1]

good positive outcome! let us know for sure.

[artvonne]

Sure glad you got it solved Wayne I was going to return your call Sun and tell you to switch to McDonalds   


good luck

  lol

[wal1809]

Hello Luvrbus,  I am going fishing tomorrow because the white bass are going ballistic at Somerville.  I will be on the road to the airport after 5 pm to pick up my wife.  I'll have my telephone with me.