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General Information => Troubleshooting => Topic started by: ORCoaster on May 27, 2012, 08:57:51 pm
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Blowing the little rubber return lines off the injectors and diesel or WVO is going everywhere. Not going to get better mileage doing that.
Does routing the outflow of the IP really introduce that much pressure back into the pump that there would be enough pressure to pop off the hoses? I replaced or cut the ends off those that were long enough and I think I have them tight but I am not sure that is going to work when the car is cruising along at 65. then the IP generates between 63 and 80 lbs. If I am popping the hoses off at idle I seriously doubt they will take those higher pressures.
Anyone running a closed loop return with success?
I may need new hose altogether. I found one broken fairly far down from the nipple. Might explain why I was seeing MPG drops. And occasional spots on the ground.
What I don't understand is why I haven't had a problem until I switched it to the closed loop system to purge the IP. I have had the car wrapped up on extended grades plenty and the IP pressure has touched 100 on the gauge just recently.
Let me know your thoughts. DAS
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Years ago, when I converted a Rabbit to WVO I ran a looped system with no trouble. If it's just looped back to your feed line form the tank there shouldn't be any way for it to build pressure. Sounds like you must have a restriction in your return line somewhere.
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^ this
I ran thousands of miles looped, on diesel and WVO.
If you close the purge line, and forget to open the loop return, the hoses blow off.
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Well, I thought I had it right and the solenoids were working as far as I know. Might be time to run some ATF as the WVO side and see what is going on with some clear lines and a recirculation can.
I did have to switch the solenoids around a bit to get alignment right for the in and out of the diesel. Maybe the fuel coming out the OUT banjo is hitting the wrong side of the valve body and is not flowing through but backing up instead.
I will keep hunting down the works.
DAS
Edit after searching and turning brain on or off? Why I had it in my mind that the return flow from the IP had to be after the main valve I don't know. Something about replacing the WVO with diesel through consumption rather than back flushing the WVO side for the few minutes it would take to get it out of the IP and get diesel in. Anyway I think if I go back to the way I had it, with a tee just before the main fuel selector side that will take care of my problems.
Then when I am in purge mode the diesel is coming into the pump and has no place to go but back down into the WVO lines and FPHE. That might mean I get a little diesel in the works but better that than sending the WVO to the main diesel tank. I just need to know about how long that flushing will take. My guess at idle I would move the contents of the IP and the lines in roughly a couple of minutes. So at 40 mph and in fourth gear less than a minute?
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When I try clear vinyl for air it broke to,but after I put real tube no problemo.When I drove on oil I mostly use loop all the time,I use my only one electric valve to bypass sometime to oil tank or air purge.
On idle if I do FULL purge I need ~ 2 min.
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2 minutes is about what I was thinking. Could set it up on a timer and have it kick off automatically if I wanted too.
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Well how much fluid can the pump hold? Quite a bit, IIRC something like one half liter or more. From previous tests of my own it took forever to idle through 100ml of fuel. And an eternity to run through my 1L fuel bottle that I was using for a controlled test fuel tank.
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Well how much fluid can the pump hold? Quite a bit, IIRC something like one half liter or more. From previous tests of my own it took forever to idle through 100ml of fuel. And an eternity to run through my 1L fuel bottle that I was using for a controlled test fuel tank.
But the return. Giles said something crazy like the return flows a .5L per minute or something on a healthy pump, that is when mine was giving me fits and I had a bottle hooked up and it wasn't returning near that much.
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Lol. my bad, yes it does return something stupid amount to the tank.. I forgets
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Well how much fluid can the pump hold? Quite a bit, IIRC something like one half liter or more. From previous tests of my own it took forever to idle through 100ml of fuel. And an eternity to run through my 1L fuel bottle that I was using for a controlled test fuel tank.
But the return. Giles said something crazy like the return flows a .5L per minute or something on a healthy pump, that is when mine was giving me fits and I had a bottle hooked up and it wasn't returning near that much.
the pump does something like 12-15gph...
so, not much!
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Well how much fluid can the pump hold? Quite a bit, IIRC something like one half liter or more. From previous tests of my own it took forever to idle through 100ml of fuel. And an eternity to run through my 1L fuel bottle that I was using for a controlled test fuel tank.
But the return. Giles said something crazy like the return flows a .5L per minute or something on a healthy pump, that is when mine was giving me fits and I had a bottle hooked up and it wasn't returning near that much.
the pump does something like 12-15gph...
so, not much!
.225gpm interesting.
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What were the late Hagar's specs on the outflow. He said if at idle it should crank out something like 600 ml in 90 Seconds? Wait let me go look, I had all his specs on a Word document and it might be on this laptop or the other computer up north.
Hagarisms:
Pressure in pump MUST be 43.5 Psig at 1000 RPM engine, and then this one
" If the IP flow is less than about 25 litres per hour at idle ---you will never get to really great Smileage."
14 US fluid ounces = 414.029414 ml per minute. 414ml/min X 1.5 min = 615 ml
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You forgot the use of EH
...and *editing my own comment before posting something about a dead guy*
other than that sounds like something he would have posted.
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I use one 3 port fuel select valve, a manual ball valve to open or close the return loop, and another manual ball valve I can open to purge into an oil bottle tucked behind the battery if I need to bleed.
Switch a mile or two from home, and never had issues.
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Well, I put it back the way it was and of course it still has issues. Once weak always weak is the lesson here.
The excessive pressure that was popping the injector return hoses off is no longer present but the fact that the nipples are lubed and the hoses weak cost me some fuel on the trip up. I think one went to leaking the last hour of my ride. I have several sustained grades to pull and the Bio Diesel I am running is not as peppy as the regular stuff so I have to drop a gear, or two, and wind it up. That gives me internal IP pressures near or slightly above the 100 PSI mark.
So perhaps the thicker fuel is going to cause me to reduce the IP pump pressure by tapping back down on the regualtor. It is also sending me to the store for new line as I hate the mess it is making all over my newly installed stuff. Dang it Jim!
Hoping to get this sorted out ASAP but time is short and patienace even less.
DAS
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This is an interesting read. I suppose the pump was designed to flow lots of fuel back to the tank just for the sake of maybe heating the fuel at least a little bit. If you have ever felt the diesel coming out of the return on a pump that has been running for some time its remarkably hot for what it is.
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From what Giles told me the hot fuel is flowing out of there to get cool fuel in and cool the pump
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Cooling the pump is why it flows so much back to the tank is what I understand as well. That injector sitting right in the block gets might warm and not all the fuel goes in. It actually helps with heating up the WVO to a desirable amount.
I have a very sensitive theromo gauge attached to the inlet line of the IP to monitor the temperature of the fuel going in and on diesel alone, not even heated it runs at about 110 because my inlet line is draped across the top of the timing belt cover and then sort of around the mix of hoses I have going now for the WVO system.
I am not sure what the temps will be once I start recycling the oil through the pump, and mixing it hot oil from the FPHE. The goal was 160 degrees. I had an air lock on that heater I resolved last weekend but have not switched the closed loop hose due to lack of time.
I will say that the car is running a lot quieter on the Bio Diesel I have been putting in to it lately and that the miles per gallon is better when I mix it 50/50 with Regualr Diesel. Still unknown what the WVO will do as I haven't run on it yet. Proving the system first with BioDiesel.
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Temp on return on Disel only, on 25c outside,on full temp motor is 60c (on my car) and that isn`t cloosed loop or heated before pump of corse,every vane/gear pump MUST give up temp.It`s easy to measure because my d tank is ~ 2 lit VW overflow jug.
ps.How old d like ours work so well in Sahara desert and Arabia,look like old d is better lube.
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I am converting an 81 rabbit for wvo right now, I heard that the closed loop can introduce air into the fuel lines. Is that true? Also, do you guys use an extra fuel pump for the wvo to reduce wear on main fuel pump?
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JD, Question #1 If you do not get all the fittings taped or tight or puttied air will get in. The Closed return can eventually produce enough air into the system that you only have a foam in the pump rather than fuel. I had that trouble yesterday and had to take it off veg oil back to diesel and then I could continue on my way. I tried it again after the car sat all day and I got 10 miles down the road and it was starting to power down, and sputter so I put it back to diesel and will source the air leak again this weekend. The triple whammy is once air gets in you are recirculating it with the closed loop rather than dumping the air back into your second tank. That is an option but it takes a third three way solenoid to do it. Or one of those 6 way valves that fall apart after a short while. I am using well built valves that have big openings and no flow restrictions.
Question #2 I do not use an extra pump. Why not? Did VW throw one on there in 1981? No it is a drawn to the pump system not a push to the pump system. The solenoids I use are not designed to have fuel pushed at them anyway. No how does deal with the thicker fuel being drawn to the pump? You have to heat it in the tank. Several ways to do that I am sure you are researching that. I purchased an aluminum tank, with baffles and an aluminum tube at the bottom for coolant. All professionally welded. Expensive compared to the five gallon plastic diesel jug I have seen some try to use but I think it is necessary.
My oil is heated to whatever number of degrees I want to let it go to but I can shut the heat off to the tank at any time. My heat system is split from the engine, it is separate by using a FPHE (Flat Plate Heat Exchanger, for the non WVO crowd) a 12 vdc oil pump and standard coolant lines. I did not go the hose in the hose route only because the guy I bought my tank from also sold me all the hoses he had that went with it. I think Pex tubing inside a 5/8 inch line would do well in a Rabbit. My son did copper tube inside the coolant line and fabricated the hose bib and compression fitting combination to make it work and not leak.
I heat the oil in the tank to 85 degrees, draw it through a 3/8ths inch diameter line to a 10 micron filter that has one of those VW oil coolers between the filter and the flange. I use it in reverse to heat the oil not take heat away. From there the warmed oil goes to a Racor 2mm filter with a water separator, dropping down to the FPHE that is just before the pump and solenoid valves.
I will run my tee from the return to tank or loop solenoid to the line just before the FPHE this weekend as I think there is to much vibration at the pump area and I am getting air in there. That will also increase the temperature of the incoming fuel and not blend it with what was just in the pump and cooled down.
If you need more information and pictures give me a PM and I will share. I should do a build thread but I need to rebuild the head, fix a washing machine and work on the house this weekend for starters.
later DAS
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I am converting an 81 rabbit for wvo right now, I heard that the closed loop can introduce air into the fuel lines. Is that true? Also, do you guys use an extra fuel pump for the wvo to reduce wear on main fuel pump?
Not more that open loop, but;
1- it willl pull air as your filter clogs if everything isn't tight.
I'd get a lot of air in the veg side supply when changing filter element. Get on the highway, and toggle the switch to diesel when it bogs... a dozen or some times, and air is purged.
2- extra pumps are another point for air to enter, I had one that would draw air internally. It's not needed, but Cummins uses them on the VE pump. I have one plumbed that I only activate if I want to prime, or need a bit of filtered diesel for something. It really helped before I resealed my pump.