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Old 12-13-2019, 09:00 PM
Loxley Loxley is offline
Join Date: May 2016
Location: wanderer
Posts: 49
Question Veggie Tank Not Emptying

OBS with BFT V4 & Azfuels/VeggieGarage e-fuel & stainless steel hoses. Have been running it on my vehicle successfully for 3 years. Thank so much Jay & Dave! You've been very helpful over the years. :-)

I know my veggie tank gauge is working because when I start the vehicle, the veggie tank needle rises from empty to half full. However, as of a few weeks ago the veggie tank needle does not go down towards empty when the OLED display system monitor reads "On". My diesel tank does seem to be emptying. Also, the green light is no longer lighting up on my switch when in “auto” mode; however, the green light does come on when it is switched to “manual” mode.

I put a new Donaldson filter on the V4, pulled out the pre-screen and installed a new one, pulled out the Manifold Check Valve in the V4 manifold and let it soak for a few hours in diesel fuel cleaner. In the BFT Preventative Maintenance Instructions it says that "over time, the check valve may stick open, allowing diesel fuel to enter your WVO fuel tank ... expected life for a manifold check valve (with annual cleaning) is about 2-3 years (shorter if no cleaning is done)." After changing the veggie fuel filter, pre-screen and Manifold Check Valve, my tank aux veggie tank appeared to be holding the same amount of fuel.

After that, I ordered the V4 Maintenance Pack & a Purge Solenoid. I have thus far replaced the pre-screen mesh, Manifold Check Valve, Purge Solenoid, Donaldson, the fuses in the SSB. I tried to replace the Electronics Module relays on the SSB but I could not pull them off the board & stopped tugging because I didn't want to break it. When I pulled the original Manifold Check Valve off the V4 I did the pen cap test & the valve did spring to life just fine, so I think the original is fine. I will keep the new one installed & keep the original in my garage in case the new one ever fails.

I'm still having the same issue though where the veggie tank needle does not go down towards empty when the system monitor reads "On". Yet my diesel tank is emptying. What might my next trouble shooting step be? Replace the pressure switch? I've found the V3 pressure switch part on the BFT website, but not the V4 pressure switch. Or should I change the 7.3L engine block SS Check Valves?

I’m attaching images including one that looks like a possibly poly clog on one of the veggie fuel lines.

Thank you all in advance for your help. :-)
Attached Images
File Type: jpg POLY_in_fuel_line_2019.12.13.jpg (87.9 KB, 6 views)
File Type: jpg POLY_in_fuel_line_close_2019.12.13.jpg (88.1 KB, 4 views)
File Type: jpg POLY_in_fuel_line_closer_2019.12.13.jpg (94.8 KB, 6 views)
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Old 12-14-2019, 08:25 PM
greaseguy's Avatar
greaseguy greaseguy is offline
Senior Vegistroker
Join Date: Jan 2014
Location: Gilpin County Colorado
Miles on Grease: 85,000
$ Estimated Saved: almost enough for repairs
MacGyver Rating: 3.8
Posts: 377
Default No green light in auto?

Basically your post says your system doesn’t turn on in auto mode, no green light? You get a green light in manual mode. I would check your pump. Pull or remove pump from v4, plug pump in and turn on v4 in manual mode. Pump should spin. My guess is your pump is not making pressure due to death or dying pump. Green light only comes on in auto mode once pump is up to pressure and diesel pump turns off. Poly on fuel lines shouldn’t effect anything unless fuel line is totally blocked. Do you have any blown fuses?
1999 early F250 EC, SB, ZF-6 Lariat V3 DFA
425,000 miles and counting
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Old 12-16-2019, 05:02 PM
Gettin Greasy
Join Date: Oct 2009
Posts: 744

Assuming that your problem is as described by Greaseguy and not knowing your location or ambient temps and I only having a V3, I will share some of what I have learned in over 200k on grease in northern Wisconsin.
Your pump Will run in manual even if your oil is not up to temp, but running on diesel. If your pump is worn it should draw some oil before the oil gets to warm and then shut off as oil gets hot. I have no luck at all running any oil with any amount of chicken fat with ambient temps below 70* F. I have spent hundreds of $ replacing valves, lines, filters etc, only to find out my oil was not hot enough to maintain light in auto. With temps often below 0*F my truck can maintain the oil temp but it is critical to start out with hot oil. 95% of my problems disappeared when I installed an electric preheater in my tank for winter use. My truck sits outside and it costs me about .25 per day to start out with hot oil as compared to hundreds of $ spent on diesel and the frustration of not being able get my unit up to temp. I have successfully run oil at -23*F all day without a flutter. Also if your pump is weak it is possible to determine by filling your tank to the top and/or applying a little air pressure to the tank with oil up to temp and auto on.
DESCLAIMER* don't apply much air pressure. JMO
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Old 12-30-2019, 06:39 PM
Fordnut74's Avatar
Fordnut74 Fordnut74 is offline
Mad scientist
Join Date: Aug 2008
Location: Good Question
Miles on Grease: 250,000
$ Estimated Saved: -45,000
MacGyver Rating: 8.5
Posts: 1,229


As the others have stated, sounds like a lack of pressure issue to me. I can't remember what the OLED reads when up to pressure, but ON just means the system is "Armed".

Did your system just stop working one day, or did you start having issues on occasion that progressively became worse to the point of not working at all?

Unless you pumped Pea-gravel in your tank filters will begin to plug up over time and you'll notice the system reverting to diesel under heavy acceleration, then slight acceleration, then constant flashing. This is regardless of engine temperature.

If it's the pump, you'll see similar to above, but it will be more dependent on engine temp than engine load. Stuff getting caught in the pickup in the tank will cause all kinds of chaos. Typically with a plugged inlet to the pump it will whine quite loudly. One way to check the tank supply is to remove the supply hose off the manifold and you should have a small but steady stream of fuel pouring out. This is best done after the truck(and tank) are warm.

Let us know if you've made any headway!
1999 F-350 Lariat 7.3 385,000 miles and counting
2000 VW Jetta 2.0
1966 Jeep J-300 with EFI 351W
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check valve, filter, pressure switch, purge solenoid, tank

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