stalling engine while on wvo or while purging

[steepcreeker]

So the system is installed in the L400. I have two dedicated WVo tanks , a small Diesel tank and three three port valves to do direct return to deisel, to WVo during purge and to loop return while running WVo. I am using a vegtherm Max and the veg filter from Plantdrive.
My problem is that the engine stalls when I am idling in wvo or purge mode. It does not when I am in diesel only mode. It runs smooth above 800rpm through the upper spectrum. There is no lag at any running speed.
When starting up after a stall, it takes 2-3 times the normal crank and produces a cloud of black/grey smoke. Normal running produces no to just a tiny bit of smoke during heavy exceleration.

Any thoughts to help would be great.

Shayne

[mararmeisto]

Not knowing quite how you've configured your system, it almost sounds like your diesel line is not opening during the purge and you're actually purging with air (and not fuel). Just a thought...

[BCDelica]

Not knowing how your system is plumbed, would guess that you have a small air leak in the WVO side of the system.

[steepcreeker]

Today, tried putting clear tube between vegtherm and valve, where only WVO is when turned on. Kept vegtherm off and ran it to see if any bubbles where visible. None were. Some suction on hose though. WVO was at 48 C.

[mrdueck]

Where is your return line going? My friend had similar symptoms and had the return line going to the high presure side of his fuel pump. If you don't have a fuel pump inline on your system I don't think this will be the issue. The other thought I have is that your return line on the veggie side is restricted. Are you sure your valves are working correctly?

As already stated, pics and schematic would be helpful.

[after oil]

are any of your lines 1/4" ? wvo has a hard time passing through. perhaps there is a restriction in your return, perhaps the return valve or its electronic signals are reversed...

[Adam]

Have you tried adding an Aux. electric fuel pump on the WVO supply side. It eases any air leak problems by slightly pressurizing the supply (6 p.s.i.). I put two on my system which makes eliminating air locks a lot easier.

[steepcreeker]

I have cleared out the lines for the WVO side and have also increased my idle speed to about 500-600 RPM. The WVO does not stall out now at any time. It still starts very rough when I park a short while in wvo (engine Hot still). I am still getting a stall when I am in purge or just starting Diesel again. After about 1 min of running it no longer stalls. I will check the return valve connection tomorrow.

[jessef]

L400's idle best around 800

[shampoomotor]

I have cleared out the lines for the WVO side and have also increased my idle speed to about 500-600 RPM. The WVO does not stall out now at any time. It still starts very rough when I park a short while in wvo (engine Hot still). I am still getting a stall when I am in purge or just starting Diesel again. After about 1 min of running it no longer stalls. I will check the return valve connection tomorrow.

Was wondering if this was the final answer. I'm having similar problems. Surging and stalling while coasting or idling. I've spent the last five months trouble shooting and researching and all I come to is that my heat exchanger is not heating the wvo enough. The coolant exiting the exchanger is hotter than that going in. Is this correct? The coolant ceases to flow if I'm not on the accelerator, the engine surges as though there were air in the fuel when there is none. Should the coolant be circulating at all times? The exchanger is at times 50F cooler than the engine. shouldn't they be the same temp? Do I need a pump on the coolant lines? The exchanger is the highest point in the system, is this okay? The exchanger is installed upside down, is this okay? I really need some help with this, I've been over every clamp and hose, been stranded on the road more than once, been showered in coolant and oil at alternating times and I am deathly afraid that all the cold wvo (95F) is ruining my IP, injectors and pleasant disposition. The engine runs like a top on diesel.
"Help me Obi-Wan you're my only hope."
Thanx Delica forum!

[mrdueck]

Ditto on this issue. I just finished my conversion this week while in Kelowna and am wanting to get back to Wpg on WVO. I have identical symptoms to the first posting on this thread. This is my fourth system install but first on a Delica. The return is looped to the low pressure side of my lift pump. Lift pump is set at about 8 psi. I'm afraid to do more than this as I don't want to damage the IP. It is a two valve 3 port system. Going up the mountain this morning to BigWhite on WVO it worked good until I came to my first extended decline of about 15 seconds and the motor died. Put the switch on purge and it eventually started on diesel and worked fine. Drove back to Kelowna on diesel and it ran fine. I'm going to disconnect my return line tomorrow and see what is happening with it. We leave for the Peg Saturday and I'll go on diesel if I don't get this figured out by tomorrow night. Any thoughts would be of GREAT help. (not to mention saving me about $400+).
Rudy

[delicat]

Bizarre all you guys are getting similar symptoms. WVO set up is pretty basic and not trying to say you plumbed it the wrong way but is this how you guys have it? It might be very basic for some but might help newly interested members...

Two valves, supply & return (looped)

Supply: (WVO in, diesel in, WVO or diesel out as selected.)
WVO tank fuel line to input 3 way supply valve. Best to use 1/2" hose if possible but not a must.
Diesel tank fuel line to input 3 way supply valve
WVO or diesel as selected from output supply valve to IP (injection pump)

Think of the supply valve as a "Y" with two entry and one output.
The other way for the return, one entry and two exits...

Return:
When on WVO; oil goes in the valve input and exits to a "T" into the wvo line before the IP so it's looped and reuse hot oil instead of sending it back to tank.
When on diesel; fuel goes in the input and out to diesel tank (to get rid of any air in the system)
When purging; diesel goes in and loops again to the T before the IP to avoid returning WVO to diesel tank... Keep it in that selection for too long and your van will start running rough and eventually die (air in system can't escape, looped in

In my case I have my WVO fuel line coming from the tank going first to my heated filter then into the 3 way supply valve but I've seen it going to the valve before the filter which might be hard on the valve when oil is too cold?

As for heat exchanger (HE), the coolant coming out should be cooler than the one going in... Something wrong with original post. In my case I had to "T" before my HE so that the HE would get proper hot coolant flow all the time heater core valve design) but not sure about the Delica. If you could force all the coolant in line through the HE that's how you'd get the best heat for your oil but it might only work when you have the inboard heat on (passenger cab)... Food for thoughts.

Anyway, all these symptoms sounds like air in your system, nothing more, nothing less...

Cheers and sorry for the long post!
Mr. D

[jessef]

You guys may be experiencing what I did.

My problem ended up being air getting sucked through the diesel return line at the valve.

Running up a long hill on wvo, it would begin to lurch and eventually stall. Switching back to diesel after a hard start (lots of smoke/air) it would be fine. Switch back to wvo and repeat down the road.

[mrdueck]

Thanks for the comments. It's my 4th WVO install so I'm confident the plumbing is correct. I didn't have my garage with me in BC so I was limited with what I could do. I was able to determine that air was getting in the system when exiting the return on the returnline that was looped. All lines where tight so I decided to run a return to the tank so that the air would be dealt with there. Well this resulted in no change. I'll diagnose more when I get home. It ran on WVO over the mountains stalling 2x's when I was coasting or came to a stop. Restart on diesel and fogged out any living organism that happen to be in the air. The sollution was to flip to diesel everytime the load was going to be reduced or brake with my left foot and keep the idle up with the right foot.

I'm in Medicine Hat and now out of veggie so I'll diesel it the rest of the way home. My plan is to pull the valves and check for leaks. I'll keep you posted.

Rudy

[jessef]

Rudy

Sounds exactly what happened to me. Air was the culprit in mine.