Stalling on both Purge and Grease
December 6, 2012 - 10:15pm
Hi All,
This is a F250, 6.9L diesel with about 50K of veggie miles. Driving on veggie started to get less and less power lately, which usually in my case just means it is time for a new veg filter. I have a vacuum gauge installed, and usually it will show around 15 when it is time to change the filter. This time it was showing only about 5-10, and stalling after a few miles of driving on veg, stalling sooner and sooner, which was the first unusual thing to see.
Nevertheless, i changed the filter, just so that is ruled out as an obstruction. After filter change, exact same symptoms at the same times, so filter has nothing to do with this issue. (It is not unusual for the truck to stall once after switching filters with ATF in it, but usually I can get the air out after a bit of freeway driving, and switching from diesel to veg in increasingly large increments of time, until it is driving without stuttering after a while.)
It stalls when switching over to veg, after about a minute. I then have to switch directly over to diesel and start a few times. When I click the purge now, even if it has been driving on diesel, it will stall after about 30-40 seconds on purge. I then have to switch over to diesel, and then start a bunch of times, after it finally slowly runs, until it is all diesel. I've also noticed on hills that even on diesel it is not quite as powerful as it used to be.
So the big difference this time is that it stalls when i purge after about 30 seconds. What is the likelyhood that this has anything to do with a liftpump not working well anymore, or is there an obstruction somewhere in the veg fuel line, say in one of the solenoids, or perhaps in the intake? I filled the 40 gallon tank all the way, thinking that perhaps the pressure of the 40 gallons would push whatever obstruction might be in the lines out, that did not change the results either.
Any ideas where to look?
Thanks,
December 8, 2012 - 12:46am
#2
Thanks for the ideas. I can rule out the filter, will get the lift pump checked next.
December 8, 2012 - 9:55am
#3
rule out the filter
Diesel filter?
Make sure the diesel side has no problem first.
December 27, 2012 - 1:35pm
#4
thanks again for the advice. I did end up getting an oil and filter change, including the diesel filter to get that out of the way. The lube place replaced the diesel filter and then was unable to bleed the air out. It has taken me at one time about 20 minutes of cranking to get that air out as well, but i never used the schraeder valve. The lube place did use that valve to try to bleed the air out. However, because the installers of my system changed the location of the lift pump to be after the diesel filter, it makes using the schraeder valve suck air into the fuel system, rather than bleed it out. I did not install my own system, so I was oblivious to that. Since we couldn't get it started, I towed it to a nearby mechanic, who then replaced the lift pump, since the pump was bad at this point. Unfortunately, the mechanic disconnected the veg system, in order to focus on the diesel system. Then they maintained that the lift pump has to be before the diesel filter and the veg system (due to the sucking air into the diesel filter issue), rather than after, so they cut the veg system out, and piped it back to the original.
Is this diagram the same as for an F250? In other words, is the consensus to have the liftpump sit right before the IP, afte the supply valve?
http://s105.beta.photobucket.com/user/FossilFool/media/GreaseCarsystem.j...
thanks!
December 27, 2012 - 8:18pm
#5
replaced the lift pump, since the pump was bad
So your diesel and veggie shared the same mechanical lift pump.
A defective lift pump would give you problem on BOTH diesel and veggie.
I would say they fixed your problem.
Then they maintained that the lift pump has to be before the diesel filter and the veg system (due to the sucking air into the diesel filter issue), rather than after, so they cut the veg system out, and piped it back to the original.
This is the original and better set up since the lift pump is before the filter you don't have to worry the air in the filter.
The lift pump would push the air out easily.
Since the diesel and veggie share the same lift pump, the lift pump has to be in the common path of diesel and veggie.
So the lift pump has to be installed between valve "A" and the injection pump.
Now your lift pump sit at the most remote location from your fuel tank.
Most of your fuel supply lines before the lift pump would be under suction/vacuum, easy to have air leak-in problem
and hard to bleed.
Fill up the diesel filter bowl/veggie filter with diesel/veggie after filter replacement would help to bleed the system.
Is this diagram the same as for an F250?
I would say YES. This is the set up for the diesel and veggie to share the same lift pump.
is the consensus to have the liftpump sit right before the IP, afte the supply valve?
YES since the diesel and veggie share the same lift pump.
You have to restore to your greasecar set up to run veggie.
Suggest to install a fuel presure guage inside the cab to monitor the fuel pressure after the lift pump.
You can tell the performance of your fuel supply system, both diesel and veggie.
January 5, 2013 - 5:36pm
#6
Thanks again Veggpwr, this has been very helpful so far. Just one more question before i start putting it back.
I also have a Vegtherm (mega) electric heating tube right before the IP. Is the lift pump better off, before or after this Vegtherm? If after, then the veg can cool off a bit again before injection, I would think, since it is another 4 or so feet.
replaced the lift pump, since the pump was bad
So your diesel and veggie shared the same mechanical lift pump.
Yes.
A defective lift pump would give you problem on BOTH diesel and veggie.
I would say they fixed your problem.
YEs, I hope that's all it is at this point.
Then they maintained that the lift pump has to be before the diesel filter and the veg system (due to the sucking air into the diesel filter issue), rather than after, so they cut the veg system out, and piped it back to the original.
This is the original and better set up since the lift pump is before the filter you don't have to worry the air in the filter.
The lift pump would push the air out easily.
Since the diesel and veggie share the same lift pump, the lift pump has to be in the common path of diesel and veggie.
So the lift pump has to be installed between valve "A" and the injection pump.
Now your lift pump sit at the most remote location from your fuel tank. Most of your fuel supply lines before the lift pump would be under suction/vacuum, easy to have air leak-in problem and hard to bleed. Fill up the diesel filter bowl/veggie filter with diesel/veggie after filter replacement would help to bleed the system.
That makes sense, since it is a screw from the bottom, so there would just be a little air above the filter left. Will do that, or ask the lube place to put diesel in the filter bowl next time.
You have to restore to your greasecar set up to run veggie.
Suggest to install a fuel presure guage inside the cab to monitor the fuel pressure after the lift pump.
You can tell the performance of your fuel supply system, both diesel and veggie.
I have a fuel pressure gauge under the hood now, but yes, extending it into the cab would definitely be a better setup. Thanks
January 5, 2013 - 6:51pm
#7
I also have a Vegtherm (mega) electric heating tube right before the IP. Is the lift pump better off, before or after this Vegtherm? If after, then the veg can cool off a bit again before injection, I would think, since it is another 4 or so feet.
It depends on your switchover coolant temp.
If the switchover coolant temp is high, the veggie temp before the lift pump is warm enough for the lift pump to work without stress,leave the heater after the lift pump to boost up the veggie temp before the IP.
If the switchover coolant is low, leave the heater before the lift pump and put insulation on the fuel line between the lift pump
and injection pump.
Remember you don't want to heat up your diesel fuel going to the IP with your heater.
Don't forget to switch it with your manual cutout switch when you are have no intention to run on veggie for some reasons.
January 5, 2013 - 8:06pm
#8
THanks,
Yes, just put the connections all together, and have been cranking, looks like the batteries will need a charge overnight, as they're about done. I put as much diesel in the pieces of fuel line as I could, so there shouldn't be too many air pockets. I have no idea what the switchover coolant temp is, I'm assuming the temp gauge inside the vegfilter is a good indication. So for now have put the lift pump before the vegtherm. I don't turn the vegtherm on until i'm ready to switch to veg from diesel, then i usually turn off the vegtherm, once the veg inside the coolant heated veg filter is showing above 100 degrees. So usually after about 5 minutes of driving on Veg, I turn the vegtherm off.
I have the vaccum gauge T'd into the fuel line after the liftpump as well, or should it be before the liftpump? I can't read the gauge while I'm cranking but it appears to be at least plus 15 psi, as I see it receding back to zero when I get back under the hood.
Sorry for all the questions, i'm just now forced to figure out the plumbing after 5 + years of driving on Veg!
January 5, 2013 - 9:34pm
#9
vaccum gauge T'd into the fuel line after the liftpump as well, or should it be before the liftpump?
The pressure after the lift pump should be positive psi. A vacuum gauge reads negative psi.
You needs a gauge that reads positive psi. Unless your gauge reads both positive and negative psi.
it appears to be at least plus 15 psi,
That 's a good sign. Was it jumping up and down or steady? The engine should start with a steady reading.
A jumping reading indicates air in the system.
as I see it receding back to zero when I get back under the hood.
Install this gauge inside the cab. Study the normal psi reading while driving.
This would be your monitoring and diagnostic tool for your diesel /veggie fuel system.
January 5, 2013 - 11:31pm
#10
I'll try and see if i have enough hose to put it in the cab, it does appear to be reading both positive and negative. It looks like the positive is limited to 10 psi, if i'm not mistaken, so I may have been wrong about the 15 psi, maybe it was just 5, see image below.
January 6, 2013 - 2:52pm
#11
The guage shows around plus 5 when cranking. after about 1,5 hour of periodic cranking, finally I decided to take the hose after final valve, and vegtherm off, and see if any fuel was actually coming out, nothing. Now i'm not sure what the obstruction is, perhaps the valve is not passing the diesel side through. back to drawing board.
January 6, 2013 - 5:07pm
#12
Current setup, hope this makes sense. I was able to poor 3 cups of diesl into the hose that goes to the diesel tank #3 below. Diesel tank is topped off by the way. I routed the biod capable hose from the supply valve to where it says 1 or IN below. Then the number 2 leads traditionally to the diesel fuel filter, but instead goes directly to the vegtherm and injection. What am i missing?
Fuel pump connections:
Diesel fuel filter connections
Veg filter and Diesel supply and vegtherm to injection:
Valves and supply:
January 6, 2013 - 5:39pm
#13
According to the route diagram:
Diesel tank-- diesel filter-- noValveAcom -- lift pump -- IP. Is this correct???
Fully charge up battey.
Fill up the diesel filter with diesel.
Disconnect fuel hose at IP. Crank until diesel come out from hose.
OR use a vacuum pump at the hose end to pump until diesel come out from the hose.
Connect the hose back to the IP.
Crank until it start.
January 6, 2013 - 5:38pm
#14
Is the lift pump electric or mechanical? I am assuming it's mechanical.
Hard to follow from the pics.
Can you gave me the exact routing info from diesel tank to ip?
January 6, 2013 - 5:40pm
#15
Which route diagram are you referring to, and what does novalveAcom stand for?
I did have the diesel filter filled up with diesel, and disconnected the hose right before IP, put that in a clean clear wine bottle, but nothing came out. I can fill the bottle with diesel to see if it either draws down, or results in bubbles to make sure there is correct flow, or any flow at all .
Is any vaccuum pump going to do, or a special pump needed? I'll have to ask around to see if anyone has one.
Thanks again!
January 6, 2013 - 6:00pm
#16
I filled a bottle 3 quarters of the way with diesel and do see large airbubbles, about one large airbubble per second while cranking. so at least the direction appears to be correct, just no diesel being drawn.
Is the lift pump electric or mechanical? I am assuming it's mechanical.
Correct, mechanical liftpump
Hard to follow from the pics.
Can you gave me the exact routing info from diesel tank to ip?
Diesel tank is #3 which (was connected by a couple inches of hose to the "IN" port of the mechanical liftpump). Now I have #3 going directly to the diesel filter #4, then out of the diesel filter #5 (which in diesel setup goes directly to IP) it now goes directly into the #8 diesel and veg supply valve underneath. on the top of the valve, you have the #9 veg fuel coming from the Veg filter, and then 11, going to the IN port of the mechanical lift pump. The pump then goes to #2, through the hard hose directly to 12, 13, 14, and finally connection #6 to the injection. That is where I have the wine bottle currently showing bubbles.
January 6, 2013 - 8:51pm
#17
""Diesel tank is #3 which (was connected by a couple inches of hose to the "IN" port of the mechanical liftpump). Now I have #3 going directly to the diesel filter #4, then out of the diesel filter #5 (which in diesel setup goes directly to IP) it now goes directly into the #8 diesel and veg supply valve underneath. ((This is the Normal Open port of valve A.))
on the top of the valve,((This is the Normal Close port of valve A. The one located all the way to the top)) you have the #9 veg fuel coming from the Veg filter,
and then 11,((This is the Common port of valve A,)). going to the IN port of the mechanical lift pump. The pump then goes to #2, through the hard hose directly to 12, 13, 14, and finally connection #6 to the injection. That is where I have the wine bottle currently showing bubbles.""((pumping air))
I am referring to the routing diagram from your pic link which is for Mercedes and you have the same setup as that diagram.
Check to make sure the connections to the ports ( NO/NC/COM) of valve are correct.
Whatever you post above is correct if the connections to ports of supply valve A are correct.
You have to prime the fuel lines from IP then lift pump and back to the diesel tank with diesel then your lift pump can start to pump.
A vacuum pump would do the prime.
Was it running with diesel before you try to restore it back to run veggie?
Do you know whether you have a check valve somewhere in between your diesel tank and your diesel filter?
A check valve would help to prevent the loss of the prime.
January 6, 2013 - 8:04pm
#18
Is any vaccuum pump going to do, or a special pump needed?
Any vacuum pump that is used by auto mechanic to check for vacuum or to bleed the brake system.
January 6, 2013 - 8:50pm
#19
Will have to read that a few times to understand. Yes, it was running great with diesel, all power was back. I made sure to run around on just the diesel setup with the new liftpump for at least a week, before hooking up the veg system again. So I know for sure the previous setup,
diesel tank->liftpump->diesel fuel filter->Injection
worked without problems.
Now that the pump is after the Diesel fuel filter and tied to the veg system i'm having problems. I'll call my friend to see if he has a vaccum pump that could assist with pulling the fuel out. Some on the Ford 6.9 L diesel forums say that some mechanical pumps don't like pulling as much as pushing fuel, i'm assuming that is why you're recommending temporarily hooking up a vaccum pump. No idea if there is an additional check valve between the D tank and the D filter.
thanks for all the help so far!
January 6, 2013 - 9:14pm
#20
Where is the lift pump located?
On the IP or somewhere on the engine block near the oil pan?
Not familiar with your truck.
If there is no check valve there, use an electric fuel pump to push diesel from the IP hose back to the diesel tank
would do the prime too.
January 6, 2013 - 11:12pm
#21
buy one of these... put it at your veggie tank and hook it up to a battery or battery charger and prime the lines with fuel. you can even leave it on to start the truck.
http://www.ebay.com/itm/Ford-7-3-diesil-fuel-pump-/160950025108?pt=Motors_Car_Truck_Parts_Accessories&hash=item25795e7b94&vxp=mtr
http://www.ebay.com/itm/NEW-FUEL-PUMP-INSTALLATION-KIT-FORD-PICKUP-VAN-7-3L-DIESEL-E2236-/170967326952?pt=Motors_Car_Truck_Parts_Accessories&hash=item27ce7260e8&vxp=mtr
http://www.ebay.com/itm/00-03-FORD-EXCURSION-V8-446-7-3L-ELECTRIC-FUEL-PUMP-BRAND-NEW-/150870142628?pt=Motors_Car_Truck_Parts_Accessories&hash=item23208faea4&vxp=mtr
January 6, 2013 - 11:59pm
#22
Thanks Brian.
I was just going through the grease parts box (several folks i know dumped their systems when the local Spokane greasecar installer left), and found this pump, would this work to get the fuel primed enough? Would you just leave it in the plumbing to turn on manually whenever needed? If so, it does not seem to create a constriction when not turned on, but it is one way, so would have to sit after the supply valve right?
January 7, 2013 - 7:17am
#23
The pump should work.
You can do it as Brian said to prime with veggie if you can hook up to the pex line inside the veggie tank.
I would permanently install the pump underneath the truck frame on the diesel supply line, close to the diesel tank,
and control it with a relay and a switch inside the cab.
Make sure there is no restriction when pump is not running. It should be that way.
So you can prime it whenever you want.
Just turn on the pump, crank to start the engine then turn off pump.
Now you have a dual pump system. I would also add a bypass ball valve across the mech pump.
Next time when your mech pump fails you can bypass it by manually open the valve and run the electric pump.
January 7, 2013 - 7:19am
#24
dont know if you can leave it on.. if your suppose to have 9 or 10 psi and that pump is 70 psi then no. or even visa versa
January 7, 2013 - 7:29am
#25
If it is 70 psi then you cannot run the engine with it. Forget the bypass part unless you add a pressure regulator.
So there are different options to do the prime.
January 7, 2013 - 11:31pm
#26
bummer. Looks like i'm going to have to buy one, this pump pictured above is not responding to 12 volts, going either direction. I'll get the one from the link Brian posted.
January 19, 2013 - 4:53pm
#27
If there is no check valve there, use an electric fuel pump to push diesel from the IP hose back to the diesel tank
would do the prime too.
Not sure I understand the thinking behind pushing fuel back towards the diesel tank with the electric pump. I'd want the pump to push or pull fuel out of the diesel tank into the whole fuel system to prime it right? Then crank, until the mechanical lift pump is working well, and then turn off the electric pump.
January 19, 2013 - 5:47pm
#28
yeppers
January 19, 2013 - 7:45pm
#29
Prime = fully fill up fuel lines, lift pump and filter from tank to IP with diesel (without air)
You can try to suck diesel out from the IP end until no air come out.
OR you can push diesel in from the IP end until no air come out from the remote end inside the tank.
Either way would do the job. It's your choice.
So disconnect fuel hose to IP low pressure side, hook it up to an electric pump and a container of diesel.
Run electric pump for a couple of minutes and the prime would be done.
Re-connect the hose back to the IP and try to crank to start.
January 19, 2013 - 7:56pm
#30
i would put the electric fuel pump as close to the fuel tank as possible. hook battery charger ( or some way to power pump) turn pump on. somewhere close to engine open a fuel line to bleed out air. then start truck. turn off electric pump and see if truck keep running
January 20, 2013 - 12:26am
#31
Thanks guys. I got the pump and first tested it. (pump from ebay, seller had rolled it in newspaper, then stuffed in an envelope and called it good, so one of the ends was bend, and end cap broken, but still worked luckily). Then I put the pump in various sections and started pumping, when it was pumping clear, repeating process, I moved on further down the lines, checking for hissing where clamps needed to be better tightened. After filling about 3 full bottles of what looked like half-decent table wine, then got to the final section between vegtherm, and IP, put some diesel in the last section, and hooked it all up, it started within 15-20 sections of cranking! Wow, who'd ever thought starting a diesel after messing with the fuel system could be so easy! Electric pumps rock! Will try veg system tomorrow after the truck thaws out on diesel a bit more (18 degrees here). will try and extend the vacuum gauge for in the cab reading.
January 20, 2013 - 9:50am
#32
Will try veg system tomorrow after the truck thaws out on diesel a bit more
Warm up engine with diesel, switch to PURGE mode for a couple of minutes to prime the veggie side.
Air on the veggie side would be pushed back into the veggie tank.
Then switch to veggie mode.
January 21, 2013 - 6:30pm
#33
Did warm up with diesel with half an hour or so of driving, and then purged for a couple of minutes like you say to clear out the veg lines. But it did stall this time on purging after about 15 minutes of driving. Yesterday it did not stall on purging, but it was a slightly warmer day, and I had done more driving. So it seems that the purge lines maybe are too exposed to the cold? we've been around 20 degrees daytime here with fog today. The veg mode seems to do OK as long as i've really warmed up the system. yesterday on the way back, was able to go 70 on veg, but still i detect a little hesitation in power. then i got home today, and just ran idle on diesel a bit, then purge, and it does not stall then. I can then run on veg. The mechanical pump sits against the engine block on the front between the block and the radiator fan. There is about three feet of biod capable thick hose going from the supply valve to the liftpump, and then through the metal hose back up to the vegtherm and injection. I'd say that is about 6 feet of exposed hose, with the pump being metal and probably transferring the cold coming from the radiator fan and driving. So perhaps i just need to do some insulating to keep that section and the purge lines warmer?
January 22, 2013 - 7:04am
#34
Looks like the veggie didn't get enough HEAT.
Switch over should be based on coolant temp.
What's your coolant temp when switch over? Recommended at least 150F.
Your engine operating temp would be 180-190F. Your veggie temp should be able to come up to at least 140-150F.
If not you may not have a good coolant circulation on the veggie coolant loop.
Also consider add insulations and a FPHE to boost up the veggie temp.
Edit: It was 23F outside here this morning. My coolant temp was 186-190F and veggie temp was 150-155F.
I have winter front cover mounted in front of radiator, insulation on coolant hoses from tank to engine bay,
Insulation on fuel hoses in engine bay and FPHE.
March 6, 2013 - 5:10am
#35
Hi OP, any luck fixing it? I might ask my cousin about this, he is quite a good mechanic. I was slightly sceptical myself initially about driving a veggie, but I have to say it didn’t feel too much different from driving other fuels when I test drove it around the neighbourhood. My cousin was skilful enough to set up the right auto parts by tapping into the hoses of his old Mercedes-Benz’s cooling and fuel systems and securely mounting the tank and valves. My guess is the same though, keep your veggie warm. Vegetable oil is usually in solid form when there’s not enough heat. Ensure that the engine coolant lines are also in contact with fuel lines.
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Stalling on both Purge and Grease.
My impression is you have fuel starvation on BOTH diesel and veggie side.
It takes diesel on purge mode and takes veggie on veggie mode.
Also you loss some power on hill when on diesel.
So lift pump, filter, fuel line restriction, air in system on both diesel and veggie side or
the part that's common to both diesel and veggie could be the problem.
I would like to fix/make sure there is no problem running on diesel FIRST.
Then worry about running on veggie.
__________________
'05 Cummins CTD 24V HPCR RAM 2500 QC SLT SB Black 4X4 48RE 325 hp 610 ft.lbs
GC Kit + 3rd Tank WVO(80%)/RUG(20%) + Co-Pilot
3-Tank Operation managed by Co-Pilot: Blending(warm up) / Veggie(hot run) / Diesel(purge for next start)
Smarty Jr 40/70/100 hp (Timing Map Modification)