Vegetable Oil SVO WVO waste cooking oil as biofuel

[SunWizard]

On my vehicle the diesel fuel return line is routed through the diesel filter. So if I use your fuel routing diagram I will have reroute the return line to bypass the filter and plug the filter housing where those lines enter? is this correct?

Yes, thats what I did on my dodge which is that way.

Also where do the 3/4 to 1/2' reducing T's that you list in your parts list go in your diagram?

Sorry I don't remember it was >5 years ago.

[compostbrain]

So I got everything hooked up on my Sprinter and bled the lines by pressurizing the tanks and disconnecting the fuel line as it exits the mechanical fuel pump. For some reason after getting all the bubbles out and trying to start I get bubbles that seem to be pulled backwards into the fuel line from the fuel pump. Does anyone have any idea why this would happen? I can't figure out why there would be a leak from that direction since all the plumbing I did is the other direction.

[SunWizard]

Sounds like the filter or connection under vacuum making an air leak, a very common problem.

[compostbrain]

If I'm pushing the fuel through the lines by using compressed air to pressurize the tank, shouldn't the leak be obvious? And why are the bubbles appearing to come out of the fuel pump heading backwards of the direction the fuel usually travels? Does this mean the leak is in the return line?

[SunWizard]

I can't understand your system without a diagram or much more detailed description.

[compostbrain]

Finished the conversion using Sunwizard diagram. I had two leaks. The first was at the stem of one of the boat valves. I think I must have tweeked it when I was screwing it to the van underside. I used a spacer to prevent messing up the angle but apparently didn't succeed. Luckily I had another valve on hand and switched it out relatively quickly. The other leak was from a brand new pushloc fitting. Not sure if it was faulty or whether a metal burr got squished on the sealing surface. At first I thought it was coming from the barbed fitting but after putting a hose clamp on I realized it was coming from the screw-on end. So far I have driven about 1200 miles with the system and things seem to be working well. Some issues I am having:

1. Couple hard starting episodes. I think my purges must not be long enough or correct. I have been doing about a minute for each valve. Is there a way to calculate proper timing?

2. My temps stay around 150-160 most of the time. I am using a 30 plate FPHE before my temp guage and IP. Ways to get this up? What have people found to be the best insulation? I already insulated a couple lines and put cardboard in front of the radiator.

3. Plugged a filter after only about 500 miles. I am hoping it was just some junk in the new lines and tank and that my next filter will last longer. I am using a centrifuge for my oil so that shouldn't be the cause. By the way I get my filters here: http://www.filterbarn.com/ they have a nice cross reference feature and are very cheap. I payed about $4 per filter from them.

I will post pics soon.

[SunWizard]

1. Couple hard starting episodes. I think my purges must not be long enough or correct. I have been doing about a minute for each valve. Is there a way to calculate proper timing?

Install a clear inline filter just before the return valve. Use dark WVO or add some dye. When the purge is done you can see the color change in the fuel. Too short and you get some WVO in your diesel tank, too long and you get some diesel in your WVO tank.
How long you run after purging determines whether there is any residual WVO in the lines or IP (30 seconds on mine.)
Hard starts are usually due to air getting in connections while it sat, and the fuel ran back to your tank, not that your purge was a few seconds short. A clear inline filter will also tell you if its air.

2. My temps stay around 150-160 most of the time. I am using a 30 plate FPHE before my temp guage and IP. Ways to get this up? What have people found to be the best insulation? I already insulated a couple lines and put cardboard in front of the radiator.

Pipe wrap insulation that is high density foam.

3. Plugged a filter after only about 500 miles. I am hoping it was just some junk in the new lines and tank and that my next filter will last longer. I am using a centrifuge for my oil so that shouldn't be the cause.

Usually its a water problem to plug one that quick. Do you hot pan test each batch and get no bubbles?

[compostbrain]

thanks for the quick response.
I don't think it is an air leak because I have a clear length of fuel line right before the mechanical assist pump at the engine and there aren't bubbles there. Also the last time it happened after only having the engine off for less than an hour after several hours driving, while that same morning it started right up with no hesitation after sitting over night. The hard start came after a recent purge where as the morning start had been after extended d2 run time the day before. I tried my standard air purging method and that didn't work so I had to use some starter fluid to get it going.

Install a clear inline filter just before the return valve

Would you install this permanently or just temporary to test the purge time? Any specific filter recommendations? It would be under the van and kind of a pain to view but I guess it would be the most accurate way to tell. Also has there been any discussion about how different throttle or driving speeds effect the purge times?

[SunWizard]

I don't think it is an air leak because I have a clear length of fuel line right before the mechanical assist pump at the engine and there aren't bubbles there.

That isn't the spot. You need to watch for bubbles in the return line while someone else hits the starter and right after it starts.

Would you install this permanently or just temporary to test the purge time? Any specific filter recommendations?

Temp. Available at any auto parts store.

Also has there been any discussion about how different throttle or driving speeds effect the purge times?

Yes, it depends on your lift pump. If its mechanical like mine, double the RPM, double the flow, half the purge time.

[compostbrain]

i

That isn't the spot. You need to watch for bubbles in the return line while someone else hits the starter and right after it starts.

ok, but what about the other circumstances. Would the air bubbles only prevent starting shortly after shut down? If it is air getting into the line in the veggie plumbing it seems like they would be purged during the purge process. If they are somewhere in the shared plumbing then the problem would occur when only running d2 also? These factors lead me to believe it is improper purging.

Usually its a water problem to plug one that quick. Do you hot pan test each batch and get no bubbles?

I haven't done this in a while. I will double check it when I have a chance...

[SunWizard]

Would the air bubbles only prevent starting shortly after shut down?

No it could be anytime. Its not just air leaks during running making bubbles, other air leaks on the pressure side of the lift pump are a problem when it sits and slowly sucks air into the lines that are higher than your tank.

If it is air getting into the line in the veggie plumbing it seems like they would be purged during the purge process.

Air builds up in high spots with large area like filters, thats why many filters have a bleeder on top. Purge doesn't always clear those areas of all air. Especially since during purge the flow is going through the D2 filter and not the WVO filter.

[coachgeo]

So, I am converting my 03 Sprinter ...

An update coming soon??

Let us know how it going for you.

On the VW TDI's with computer's in the same era as your Sprinter a resister was put into the system to "if I rememember right" fool the system into thinking it was colder outside than it realy was. This made the computer do a longer "after glow" of the glow plugs, improving ignition when still cold and prevented a good bit of coking of the engine. A search for VW TDI veg systems may give ya ideas.

Looking forward to your responce.

[compostbrain]

Everything is working good. I seemed to have gotten rid of the hard start problem I had a couple times by timing my purges more accurately and doing 1 min for each valve switch. I am surprised so many people have said the Sprinter is a hard vehicle to convert. I noticed GC is selling a kit now for $2000. I haven't had any computer issues using sunwizard plumbing diagram and didn't add a pump. My plugged filter on the Sprinter was probably due to water in the veg. I normally test but hadn't on this one batch(feeling like an idiot!), so I am reprocessing now to get rid of the water. Hopefully no damage to engine. About to take a long trip with the Sprinter, so hoping I have everything in order now. Still planning on posting some photos when I get a chance.

I have put approximately 90,000 miles on the TDI. I bought it with 140,000 on od, immediately cleaned my intake and installed the greasecar kit, but never did a egr delete. I would say about 1/2 the miles since then have been veggie, mostly long distance trips. I had to remove the tank and clean some sludge recently but other than that haven't done anything to the veg system, (plenty of maintenance on the rest) since the original install. It is probably due for another cleaning. I change oil about every 3-4000 miles. The odometer is now 230,000 and I hope to run for another 100,000....Planning to add a fphe and some valves on the coolant loop when I get a chance.