[kris_maier]

hey folks.
i finished my wvo conversion on my bj60 about a week ago. its been up and running fine up until about yesterday. i'll be driving along fine and out of nowhere i lose power and the engine dies. i gotta scramble to get the engine back on and switch to diesel immediately. sometimes I can pump the gas pedal and the rpms will go back up but it mostly just dies. this has happened about 5 times in the last 2 days.
I bought a dieselcraft centrifuge for filtering and have been doing hot pan tests (but i have read the centrifuge takes care of any water in the wvo anyways...) so I dont think it is a problem with the wvo itself. probably something going on in the fuel lines?
anyways. just wondering if this sounds familiar to anyone out there!
thanks.

[John Galt]

Sounds like an air leak in the VO fuel circuit.

[MrMoMo]

What are you using for an onboard filter? If the oil is not getting hot enough before the filter, you could be clogging your wvo filter with the "waxies" How are you heating the oil?

[veggieguy]

I'll say it sounds familiar! I've found there's 2 main reasons: An air leak (fuel pump sucks air instead of fuel) or a restriction (ie. WVO too cold, or a plugged filter). The hard part is figuring out which one!

When I had trouble with my WVO side of the fuel supply, I put a temporary jug of WVO in the engine bay and used that as my WVO tank. That helped me to diagnose where the problems were, and it kept me driving on WVO (8 L lasted my about 50Km).

Check all your hose connections. Replace your filter. It could be the stock filter. I assume the WVO flows through yours like it does on my HJ60. Is your WVO getting hot enough? I installed a vacuum gauge in my WVO supply line so I can monitor how well the WVO is (or isn't) flowing while I drive. Very helpful.

Good luck, but know you aren't alone with your problems!

[kris_maier]

well, after some trouble shooting i have figured it is air in the lines. drove around last night and everytime the car sputtered and i lost power i pulled over real quick and bled the lines. every time i found air in the lines.
i replaced all filters (stock and wvo specific filter) last week so i feel confident their not causing any problems. I am running HIH to a heated filter and then to a FPHE. DIRECTLY after the heat exchanger is my 3 way valve and then right to the lift pump. I am burning hot oil, so i feel sure it is only the air causing my problems.
I don't seem to be sucking air into the lines when at slower speeds, really only when I try to accelerate quickly or get up to highway speeds.
I have checked all my clamps and they seem to be sound. Tomorrow I will start taking the wvo lines out and inspecting them! thanks for the replies.

[veggieguy]

Sounds like we have the same problem. I've been driving on WVO for 1000's of km and I still sometimes have trouble with air entering the system randomly and with no warning on WVO, even when my filters have been changed. Once in a while the engine will completely stall and I'll need to bleed the air, then no problem and away I go on WVO. Mostly though, the engine will stumble and lose power and I'll ease off on the accelerator and "work out the air" until it's fine. Never a problem on idle, because with a looped fuel system it draws very little fuel from the tank. I've figured that one out already!

I am still looking for solutions as well, and I beginning to wonder if it is a weakness of a looped fuel system, because there's no place for the air to be released. The end result is that the fuel pump gradually "loses its prime". I never have this problem on my Benz which has a return to tank.

I'd like to create some kind of built-in air bleed into the return line, but I haven't figured that out yet. I'd be interested to hear if you can find a problem.

[John Galt]

I'd like to create some kind of built-in air bleed into the return line

What if one had a manual valve so that some of the flow [and air] could return to the tank while most of the fuel looped back to the pump?

[MrMoMo]

I'm fearing my upcoming filter change. I found it hard to get the air out of the system the first time. I don't like using the manual primer pump (and it's hard to reach with where I mounted my VO filter). The worst part of my filter is it is mounted with the filter upside down, so I can't install a full filter. This means that I WILL have air in the system that I WILL have to bleed out. I wonder about installing a "primer ball" on the downstream side of the filter (like on an outboard motor). This would allow one to push the air through to the bleed nipple on the main filter, but not need to use the primer on the fuel pump. These primer balls work really well on outboard motors, and they should work equally well with VO no? I have seen them used like this to prime spin on filters in boats...


What about putting a small bleed/check valve on the downstream side of the primer ball, to let air out while priming? This then wouldn't allow air in, but would let air out.

[veggieguy]

Originally Posted by John Galt

What if one had a manual valve so that some of the flow [and air] could return to the tank while most of the fuel looped back to the pump?

A partial loop system with a return to tank works well to bleed air out of the system. The return line would need to be at a high point so the air goes back to the tank and not back to the pump. That's how MBZ does it. There's no reason why you couldn't make that work on a Cruiser, but then you need a 6-port switch valve (other wise you will return diesel fuel to the WVO tank when you run on diesel- not a good idea or you may overflow your WVO tank!!) It also means that when you purge WVO, a small amount goes into the diesel tank. That's how my Benz works. Not a big problem, but some people don't want the diesel to be "contaminated" with WVO.

Only problem with my Cruiser is that my WVO tank is the stock tank, and there's no easy way to put a return line into the stock tank. My idea is to put in a clear inline filter in the return line to the pump, and angle it so that the fuel flows on the lower side of it to the pump and the air bleeds out a small hole I would drill in the top of the filter. I do this exact thing on my Benz (without the hole) to monitor the purge fuel, and it works no problem. When I find some time, I figure it's worth a try.

[FrankJames]

I am a little confused, you said the filters are mounted upside down, but the picture shows them right side up? At any rate, could you fill them via the bleeder on the bottom of the filter? I am imagining something with some thin hose plugged onto the filter and a little funnel on the other? A MityVac would be perfect! I like to fill my filters with diesel or a diesel cleaner, just to give it a little treat on startup.

[MrMoMo]

Originally Posted by FrankJames

I am a little confused, you said the filters are mounted upside down, but the picture shows them right side up? At any rate, could you fill them via the bleeder on the bottom of the filter? I am imagining something with some thin hose plugged onto the filter and a little funnel on the other? A MityVac would be perfect! I like to fill my filters with diesel or a diesel cleaner, just to give it a little treat on startup.

You are confused because those are not my filters. As I said "I have seen it done like this to prime spin on filters on a boat" then showed a picture of it.

The issue I would have with pushing oil back in through the drain, is the drain is currently open to the environment, and likely has a lot of dirt & crap in it. I would prefer not to push that back into the filter - though I suppose I could rig a "clean" drain.

The filter on my truck is the other way up...
Mine:


And is this the way you would configure a 6 port valve? (it's in my WVO build up thread, listed in my signature)

[joshoisasleep]

Hey Kris just emailed you.
You know, maybe it's just that when my truck is working fine I always have air in the lines, but if not then I've discovered lately that it can look like you're bleeding out air even when you're not. Recently seeing little bubbles spitting out led me to chase an air in fuel problem that turned out not to be the problem. I have heard many people say that running SVO for the first time cleans out all the years of diesel muck from the system and clogs the first couple filters really fast. Could it be that?

[John Galt]

Originally Posted by veggieguy

A partial loop system with a return to tank works well to bleed air out of the system. The return line would need to be at a high point so the air goes back to the tank and not back to the pump.

I'm running a mixed fuel blend in the tank and there already is a return to the tank. Please explain more about what you mean by " return line would need to be at a high point".

[veggieguy]

Originally Posted by John Galt

I'm running a mixed fuel blend in the tank and there already is a return to the tank. Please explain more about what you mean by " return line would need to be at a high point".

It's really my theory, since I haven't changed the stock full-loop of the return line on my HJ60, but here goes:

Do you have full-flow or partial-loop fuel set-up?

Partial loop= some of your return fuel from the injectors loops back to the inlet side of the lift pump and the rest goes back to the tank (there would have to be a "T" in the return line)

Full-flow= all of the return fuel from the injectors goes back to the tank

If you have a full-flow, you don't need to worry about air because all the return fuel (and air) goes back to the tank and quickly gets bled. If you have a partial loop, depending how the "T" is installed, some of the air bubbles could find their way back to the inlet side of the lift pump and would take a long time to bleed. On my Mercedes, the "return-to-tank" port of the "T" is higher than the "return-to-liftpump" port. Since air will always sit on top of the fuel, it will stay on the "high side" so that it returns to the tank and not to the inlet side of the lift pump. I am suggesting that if you were to fabricate your own fuel lines, you would need to duplicate this effect that is based on the fact that "air rises to the top"! Do I make sense?!

[veggieguy]

Just wondering if you discovered your problem? What kind of tank system do you use? 1 or 2 tank? Do you blend fuel? Could it be that the flow from your vegoil tank is restricted? The original tank has a filter sock and mine plugged up when I first started with vegoil. Had to drop the tank, remove the filter sock etc. A royal PITA. I've found that if the truck runs for 15-20 min when you first switch over and then loses power, it's most likely a restriction at the tank. If you lose power within 5 km then its more likely a plugged filter. Just my experience.

[kris_maier]

In double checking all of my clamps for tightness I had never been checking the 2 clamps on the short rubber hose fuel return line from he injectors back to the IP (3B). In reading around on MUD I came across a diagram showing which fuel lines would cause a lose in prime in the event of an air leak. Duh. I checked the clamps and sure enough, the bottom one (the one you can't see, only feel) was not clamped properly. Problem solved. Well, mostly. I am still getting a bit of air in the lines from time to time (meaning about every 5 minutes of so) but when I lose power i just switch back to diesel, and then back to wvo. only takes about 5 seconds for the power to return and then Im good on Vo. Eventually I will replace the clamp on that fuel line, but its gonna be a pita. Filters are new, and vo is hot. I think i solved the problem!

[veggieguy]

Congrats! A feeling of satisfaction that we all hope to achieve at one time or another! I think I've solved my problems as well with more insulation on the WVO lines from the tank.

[kris_maier]

yeah...maybe not so much!
drove around all this weekend with a new clamp on the return line and still getting air in. definitely no where near as bad as before. could it be a temperature problem? I have a heated filter and a FPHE. Directly after the heat exchanger is my valve and then about 10 inches of fuel hose to the lift pump. My thermometer is mounted in the same place as Mrmomo's, on the fuel line to the furthest injector and I switch when it gets to about 20 degrees. To cold? The lines are not insulated. I think that may be in order. Anyways, more searching and trouble shooting ahead...

[veggieguy]

Although the presence of air suggests a loose clamp, leak etc., I have found that is not the only reason. IME if there is any restriction in the WVO line (plugged filter, oil too thick, plugged tank pickup) then the result is air in the lines between the lift pump (LP) and the IP. I have a vacuum gauge on my supply line of WVO and if the vacuum goes too high (over 5HG) then air enters the lines after the LP. As long as vacuum stays low (ie. no restrictions and the LP can easily pull the WVO) then air will not enter. The only thing I can figure out is that it's a problem with a full loop fuel setup, where no fuel returns to the tank. I still plan to modify an air bleed in the return line to help reduce the potential for this problem, but I haven't got around to it.

My guess is your problem is caused by the WVO not flowing easily from the tank. Are the lines insulated all the way? If you drive in cold winter temps, that can have a drastic cooling effect on the temp of the WVO, especially when you're cruising down the highway. What about thinning the WVO with gasoline? I've added 10% gas and this can help, especially in cold winter temps. How cold is it where you live? I live in S. Ontario and for the last week it's been -20 C overnight and I've been driving on pure WVO (after warm-up of course) with no problem.

[kris_maier]

I definitly agree that it is the wvo not flowing easily from the tank which kinda puzzles me. The lines from the tank in the rear of the vehicle up to the engine bay are HIH and insulated. All the VO lines in the engine bay are insulated as well. The VO then hits a heated filter (heated from hot coolant) and then a FPHE. The hot coolant hits the FPHE first, then the Filter, and then gets sent back to the tank. In this way the hottest coolant hits the FPHE, the last form of heat for the VO before the LP and IP. The heated fuel filter is simply a copper coil wrapped around a fuel filter I bought for 5$ from an old greasecar kit The owner of which told me to use a fuel filter for an '82 Rabbit. Could this be causing a restriction to the amount of fuel the 3B engine needs?
Is the 6 port valve configuration seen above in one of Mrmomo's posts what you mean as opposed to the "full loops fuel setup" i am running?
I will try thinning the wvo with gasoline and looking into a different filter. I really want to get to the bottom of this. If other people can get this to work without a problem than I can too. at least thats how i like to think...

[veggieguy]

[Is the 6 port valve configuration seen above in one of Mrmomo's posts what you mean as opposed to the "full loops fuel setup" i am running?]

Not really. In his pic, there is no return to tank when it's running on either fuel.

[I will try thinning the wvo with gasoline and looking into a different filter. I really want to get to the bottom of this. If other people can get this to work without a problem than I can too. at least thats how i like to think...[/quote]

I suspect the '82 Rabbit filter is the problem. Those filters have a much lower micron filtering rating than a typical VO filter. I use a hydraulic filter rated at 30 micron and it works fine. The stock spin-on filter does the final filtering but this is AFTER the LP which is a big difference. The LP can push (under pressure) fuel much better than it can pull it (sucking by vacuum).

Whenever I have fuel troubles, I diagnose the problem area by drawing VO from a temporary 10L bottle with a hose stuck into it. (Fits easily in the engine compartment on the pass side of my HJ60). This is my makeshift fuel tank which can be connected into the fuel lines at any point to diagnose by process of elimination. You can drive around like this to see if the problem recurs, as long as there's enough fuel in the bottle. Be sure to carry extra fuel with you!

If you connect the hose from the fuel bottle into the fuel filter and the problem continues, it's obviously not the tank or the lines from the tank. If the problem is solved, it must be in the tank or lines from the tank.

Just keep trying, that's how we've all solved our problems!

[MrMoMo]

Originally Posted by veggieguy

[Is the 6 port valve configuration seen above in one of Mrmomo's posts what you mean as opposed to the "full loops fuel setup" i am running?]

Not really. In his pic, there is no return to tank when it's running on either fuel.

Not true - look at it again. The upper picture is running on Veggie - there is no return for the veggie at that point, nor the diesel - as neither one needs it.

Lower picture - running on diesel. No return for the diesel as it doesn't need it. Veggie is returned to the veggie tank. (to prevent a cold spot, or to purge)

[veggieguy]

Originally Posted by MrMoMo

Not true - look at it again. The upper picture is running on Veggie - there is no return for the veggie at that point, nor the diesel - as neither one needs it.

Lower picture - running on diesel. No return for the diesel as it doesn't need it. Veggie is returned to the veggie tank. (to prevent a cold spot, or to purge)

Ok, I stand corrected, but then you must have some kind of pump (electric?) to keep the vegoil circulating when its running on diesel. Cause the vegoil won't flow all by itself!

[MrMoMo]

Hypothetically yes - reality no- because I didn't use a 6 port valve in the end. That was just a thought side track. I had thought of installing an electric VO pump in order to circuilate VO when not running on it - but I ended up not doing it. I just use a 3 port valve.

[veggieguy]

I also use a 3-port valve. I've read discussions of people who have trouble with electric pumps burning out due to times when the vegoil is too thick. Doesn't seem worth it to me.

[kris_maier]

Finally burning VO! Drove out to Kelowna and back this weekend on VO with only slight problems: the snow, and what I suspect to be the VO cleaning out 25 years of diesel sludge caked into the IP. Hopefully it'll get cleaned out soon. Already switched out 3 fuel filters in the last week!

[joshoisasleep]

Originally Posted by MrMoMo

Not true - look at it again. The upper picture is running on Veggie - there is no return for the veggie at that point, nor the diesel - as neither one needs it.

Lower picture - running on diesel. No return for the diesel as it doesn't need it. Veggie is returned to the veggie tank. (to prevent a cold spot, or to purge)

Are cold spots an issue? I have no return lines...

[veggieguy]

Originally Posted by joshoisasleep

Are cold spots an issue? I have no return lines...

You'l notice in a later post that MrMoMo didn't use the return line setup. Most of us keep things stock and don't bother with a return line. Cold spots could be an issue, but if you let things warm up well before switching over, then there shouldn't be a problem.

[MrMoMo]

I havn't had any issues with cold spots - As stated above I never bothered with it. It was just thinking out loud as to how it could be done (if you had a seperate VO pump - As I do in my Ford)

I only ever switch over once the engine is up to full operating temp - so there has been plenty of time for everything to heat up.

[joshoisasleep]

On that note, I wonder if anyone has tried driving an unmodified 3b on straight veggie as people apparently do with old Mercedes? I suppose this deserves a separate thread... what are the similarities between them?