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Ridding air bubbles from fuel lines after changing vegoil filter
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I changed the Racor filter in my Vormax vegoil 2-tank system and can't seem to rid the fuel lines of air bubbles. In the past, switching back and forth from vegoil to diesel does the trick. However, this time the engine continues to die in vegoil mode. Also, I've driven at least 30 miles solely in diesel and can still sense a hiccup when I quickly accelerate. Does this mean that my diesel fuel filter needs changing? Any ideas on removing the air bubbles? Thanks in advance for the help.


2004 Jetta TDI SVO (converted by PlantDrive)
Formerly 1987 Mercedes Benz 300D - B100
 
Location: California | Registered: July 09, 2006Reply With QuoteReport This Post
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Gina

Tell me more about your system. Do you have a looped purge? I always fill my new filters with oil or diesel, which ever is the case to limit air. And you could run the purge cycle until it fills you veg filter and blows all the air back into the tank, which you could listen or watch for bubbles to subside..


Merk
03 Jetta TDI 12 gal marine tank in trunk w/copper heat exchanger no intank connections, coolant heated copper coiled fuel filter, HIH, 10 plate FPHE & two 3 port wvodesign fuel valves. Timer/relay purge.
 
Location: Etna, NH | Registered: January 19, 2006Reply With QuoteReport This Post
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Hi Merk
Thanks for your response. I have a looped system but not (I think) a purge option. After changing the filter, I switched from "loop" mode to "180" mode. After several days I'm still in this mode, switching between diesel and vegoil every 10 seconds but still have air in the system.
Recently I had some water in the vegoil which got into the fuel lines. That's why I changed the vegoil filter. I thoroughly drained the water from the diesel fuel filter. Should I also change the fuel filter?
Thanks in advance for any help you can provide.


2004 Jetta TDI SVO (converted by PlantDrive)
Formerly 1987 Mercedes Benz 300D - B100
 
Location: California | Registered: July 09, 2006Reply With QuoteReport This Post
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Update: I changed the diesel fuel filter, but am still having the aforementioned problems. I realize that my mistake was not fully saturating the new vegoil filter. Should I just be patient, konking while driving, until the air bubbles get out of the system? Does anyone know how to purge the fuel lines of air with a PlantDrive 2-tank system? Thanks in advance!


2004 Jetta TDI SVO (converted by PlantDrive)
Formerly 1987 Mercedes Benz 300D - B100
 
Location: California | Registered: July 09, 2006Reply With QuoteReport This Post
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Hopefully you've solved this by now but I hate to see you left hanging.

Did you change the filter because the engine start sputtering/ dying before the filter change or was it just time (or power loss?)?

If any of these symptoms before the change, you probably have air getting into the veg line, and a tiny air leak can cause exactly what your describing. The reason your regular diesel tank has a return line that goes back to the tank and does not loop is because any air in the system is purged this way, so we've got to be much more airtight, which is made even more difficult by the fact that your veg line and all its connections are constantly being heated when in use, and cooling when not in use.

This being said, you should be able to get the air out just by cranking, as the air injected into your cylinders then out the exhaust. (though filling the replacement filter w/ diesel will help). This is why I think you've got an air leak somewhere in your line. Some people attach a little ball pump to the line just before the injection pump and prime their line that way to avoid cranking (in any case - take breaks while cranking to avoid frying your starter)

It sounds like "180" mode is a purge option, further convincing me that you've got an air leak, since you've already been purging. Another way to surely purge would be to put a clear line - cheap 1/4 inch line from hardware store - just for testing - on the "out" bolt of your injection pump (and into a bucket or something) then watch it while someone cranks. I think they still put the "out" on top of the injection pump. Look for air. if you see less and less air, just keep cranking and you should be good. If the air keeps coming, I would recommend working your way down your veg line, including the looped return line, checking and tightening the connections. If you have hose clamps tighten them, but not so tight they eat into the line. Tighten the connectors that screw into the filter and the FPHE. Apply removable "thread lock" to these connectors if its not already there.

You could, of course, skip the whole clear line step and just tighten up your veg line. which is what I do when it feels like I've got air causing sputtering or engine failure. this has happened to me 4 or 5 times and a fairly quick shoring up of my veg line has cured it every time. You could have some other problem but I think this is the most likely and the right place to start.


greg lousy
81 vw pick up
white as old snow
 
Location: Rhode Island | Registered: August 17, 2010Reply With QuoteReport This Post
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Gina
I installed a "T" and 3/8" ball valve on the output hose of the VO filter that when opened, it will bleed off the air in the filter. A 24" x 3/8" hose is connected to the ball valve. The other end of the hose is placed into a clear 1 liter soda bottle is placed under the chassis. When no bubbles comes out of the hose, I know the VO filter is completely filled with VO oil. I change the VO filter with no spilled oil in the engine compartment. It works well for me.
 
Registered: October 30, 2005Reply With QuoteReport This Post



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Dragonfly has the right idea with the T (upside down and on pressure side of pump) , but i would use a shrader valve rather than a ball valve .


David Norwood

2001 F350 7.3 DI purchased new by me and it is the first DI experimented with and talked about on this forum.

Updated 1/2011 Alternative Fuel User Since 2003-vo is always in my fuel. Only one fuel tank. GPI/CIM-TEK spin on filterhead and 10 micron filter. Superchip. Hutch and Harpoon mods 2010. Diesel inline filter between tank and Airtex E2236 fuel pump (rated to 110 psi).Fuel pressure gauge. HOH for fuel line heat from tank to 12v lift pump. Two 12v 36" heaters, one before add on filter and one before OEM filter.

Cool weather mixes updated 2010. 100% vo to 70°. 66% to 35°. 50% to 10°.
 
Location: Upstate South Carolina , USA | Registered: December 28, 2003Reply With QuoteReport This Post
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DN
By using a Shrader Valve (tire air valve) to release the air, it would also allow a small amount of VO to squirt out the valve, thus a mess. By using the ball valve and connecting it to a 3/8" hose then into a plastic soda bottle, there is no oil mess anywhere. I've used this arrangement for over 8 yrs on my 3 conversions.
 
Registered: October 30, 2005Reply With QuoteReport This Post
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Dragonfly
If you hold a rag over the valve while doing the purge, there will be no mess.
I do understand your point of view though.

The "tire valve" is an undesireable and perhaps a misleading example (too hard to visualize how to install).

A schrader valve for a well water system is a better example because it is threaded (and available at most hardware stores). It is easy to understand how to install.

(This is similar to the early 90's OEM design for the ford diesel truck.It was part of the fuel filter subassembly.)


David Norwood

2001 F350 7.3 DI purchased new by me and it is the first DI experimented with and talked about on this forum.

Updated 1/2011 Alternative Fuel User Since 2003-vo is always in my fuel. Only one fuel tank. GPI/CIM-TEK spin on filterhead and 10 micron filter. Superchip. Hutch and Harpoon mods 2010. Diesel inline filter between tank and Airtex E2236 fuel pump (rated to 110 psi).Fuel pressure gauge. HOH for fuel line heat from tank to 12v lift pump. Two 12v 36" heaters, one before add on filter and one before OEM filter.

Cool weather mixes updated 2010. 100% vo to 70°. 66% to 35°. 50% to 10°.
 
Location: Upstate South Carolina , USA | Registered: December 28, 2003Reply With QuoteReport This Post
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DN
Good point. I did find a better Shrader valve that fits our purpose on eBay. Still not sure about catching the oil in a rag. It still seems to be a little messy, IMHO.
 
Registered: October 30, 2005Reply With QuoteReport This Post
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Thanks all of you for your helpful comments. I really appreciate it! I don't know anything about cars - just a lot about vegoil and biodiesel, so I will try to do what I can and hire an expert if needed. Last week I took the car to a mechanic and they found that there was no signal from the crank sensor and a broken EGR (exhaust gas) control flap valve and cracked cooler. These problems were fixed but the car still hiccups nearing 3,000 rpms. I will tighten the vegoil fuel lines and see if it helps. Thanks again.


2004 Jetta TDI SVO (converted by PlantDrive)
Formerly 1987 Mercedes Benz 300D - B100
 
Location: California | Registered: July 09, 2006Reply With QuoteReport This Post
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All the vegoil lines that I know of were already tight. It ran really well in diesel the other day, so I thought I'd switch to vegoil. It sputtered after running for several miles, switching every 10 seconds from vegoil to diesel and back. I switched back to diesel. The next day, running in diesel, the car konked when accelerating to merge onto the freeway. After several tries, couldn't get it to start. Taking the car back to the mechanic.


2004 Jetta TDI SVO (converted by PlantDrive)
Formerly 1987 Mercedes Benz 300D - B100
 
Location: California | Registered: July 09, 2006Reply With QuoteReport This Post



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GN
I have been replacing a few solenoid valves to HydroForce valves. I experienced bubbles in the fuel line to the IP even while running D2. Found the air leak in the HydroForce 4 valve solenoid coming from the VO input port. Cleaned piston and replaced the rubber "O" ring. No air bubbles in the sight glass to the IP.
 
Registered: October 30, 2005Reply With QuoteReport This Post
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Are there any vegoil mechanics in the Redding, CA area?


2004 Jetta TDI SVO (converted by PlantDrive)
Formerly 1987 Mercedes Benz 300D - B100
 
Location: California | Registered: July 09, 2006Reply With QuoteReport This Post
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Thank you all for your help. Sorry for the delayed response. I've been out of commission. The problem was due to a failed vegoil fuel pump. The ONE AND ONLY vegoil mechanic here in Redding had some time freed up and he fixed it. Yay!!


2004 Jetta TDI SVO (converted by PlantDrive)
Formerly 1987 Mercedes Benz 300D - B100
 
Location: California | Registered: July 09, 2006Reply With QuoteReport This Post
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