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Sort of a Blog by tim c cook describing blend results in a 92 B350 dodge cummins
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Well we finished the install yesterday and it turned out well. We did break a rusted brake line in the process so the truck is in the shop right now having that fixed. Once it is done I can do the official test drive. We did get it running on both diesel and VO, but no out on the roads as we have no brakes.

We ended up using SunWizard's fuel plumbing design with the FPHE before the VO filter(Goldenrod with coolant wrap). On the ip fuel inlet we ended up taking the steel line off and cutting it carefully with a sharp tubing cutter, and then using the original inlet fitting and pipe stub with 3/8 fuel line and 2 hose clamps over the stub. I may replace this in the future, but for now it seems to be ok.

We added a new diesel filter using a salvaged filter head and new cartridge so the stock filter is ho longer in play fortunately. Both the diesel and VO filter are easy to get to.

I will post some photos this week and report back after the shakedown cruise.


98 Jetta TDI with aluminim tank HotFox fuel pickup, HOH, FPHE, Coolant Heated VW Oil Cooler Filter,VegTherm, Injector Line Heaters, 6 port Pollak, and 3 port Pollak for Backflushing veg. filter
100,000 grease miles
B100 - B20 Main Tank Fuel depending on outdoor temps. SOLD

81 Benz 240D 3 Gallon purge fuel tank, Heated Pickup Stock Tank, 12V pump, HOH, Coolant Heated Filter, 16 Plate FPHE, Injector Line Heaters, 2 Greasecar Valves, Looped on Veg., Return to tank diesel.and Injector overflow return to veg. tank

91 Dodge Cummins

2010 VW TDI Sportwagon
 
Location: Vergennes, VT USA | Registered: May 16, 2003Reply With QuoteReport This Post
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I did get the truck out for a test drive today and it seems to be running well on grease. Same power as on diesel though it idles at lower rpms on VO. It also appears to surge a little bit, but it does not stall. If I switch to VO while idling, there is a very abrupt change to a lower idle, and then it packs back up when I switch back to D2. I am thinking I will start by checking for any airleaks on the vo side of the system as the D2 side appears to be working well.

Any thoughts?


98 Jetta TDI with aluminim tank HotFox fuel pickup, HOH, FPHE, Coolant Heated VW Oil Cooler Filter,VegTherm, Injector Line Heaters, 6 port Pollak, and 3 port Pollak for Backflushing veg. filter
100,000 grease miles
B100 - B20 Main Tank Fuel depending on outdoor temps. SOLD

81 Benz 240D 3 Gallon purge fuel tank, Heated Pickup Stock Tank, 12V pump, HOH, Coolant Heated Filter, 16 Plate FPHE, Injector Line Heaters, 2 Greasecar Valves, Looped on Veg., Return to tank diesel.and Injector overflow return to veg. tank

91 Dodge Cummins

2010 VW TDI Sportwagon
 
Location: Vergennes, VT USA | Registered: May 16, 2003Reply With QuoteReport This Post
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Slow idle and surging - These problems have always been associated with too-thick fuel, usually due to cold weather. I had these problems when I was using the small stock fuel lines and pickup in the stock fuel tank, once I upgraded to a 3.8 ID fuel system these problems largely went away even when running on cold blends. Do you have a pressure and/or temp guage at the input to the IP? I would expect the pressure into the IP when on veg is far lower than the pressure on diesel, all associated with thick fuel. It would seem that your flat plate heater is not adding enough heat unless the fuel is being restricted INTO the heater, but a restriction should show up as fuel starvation at road speeds?

From past testing I find that any temp above 80 deg f (100 F or higher preferred) into the IP works fine as long as the pressure is up to at least 7-8 pounds, I don't experiance any change in idle speed as long as these minimum pressures/temps are met. After an hour of driving my veg temps into the IP get up to about 130-140 deg f summer or winter using just the H-O-H heated fuel supply and return lines. During winter temps down below freezing I have to run for at least 15 minuits before switching to veg or I experiance a bit of fuel starvation. I do not yet have the final heat exchanger installed, not sure if I really need it.

I would say your veg is just not getting hot enough for normal idle speed, if it was some version of a physical restriction I would expect you to have fuel starvation problems (poor power and acceleration, surging, limited max speed, white smoke) at normal highway speeds?

It may be that you will just have to wait a bit longer before switching to veg. You indicate that the veg filter is AFTER the flat plate heater and is warmed with a small diameter hot water tube wrap, I have never tried the wrap technique but I suspected it would take some time for the small hot water tube to actually add enough heat to all the cold veg inside the filter to get it above 80 deg f. The filter holds at leat a pint, probably more like a quart, of ambient temp fuel so you will have to run long enough to burn at leeast half that volume before you start burning warmed fuel on a cold startup, this will only take a few minutes at speed but at idle it will take something like many minutes due to the small amount of fuel being burned and the fuel return amount at idle is only drops/min (no circulation through filter).

I don't know just how the fuel metering is handled in the Bosh VE pump but it seems that the idle speed when the accelerator is NOT pushed is controlled seperatly than when you push the accelerator, don't understand this as the idle speed adjust screw simple sets the stop point on the same control shaft that the accelerator moves?

This last winter I got caught with a thick cold 50/50 mix in my stock diesel tank when it got cold, the engine started but ran at a very slow idle, I used a stick against the seat to hold the accelerator down for a few minutes til I got enough heat in the engine to thin the blend.


Stock fuel line fitting into IP - How were you able to get a wrench on the tube nut, I never could find enough room around the fitting to be able to get room to turn the wrench? Did the nut turn around the steel line, mine was frozen to the steel line?
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post
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For the stock ip inlet we used an open ended crescent wrench (not sure of the technical name for this tool but the opening allowed us to get the wrench past the hard line then around the nut). It took some time to loosen it as there isn't mush range of motion but it came loose. The outer not spun free around the hard line. I took the whole line off and then cut it with a sharp tubing cutter.

I have not used the truck enough yet to really test the idle issue, but generally I have been switching to VO much sooner that I probably normally will. I do have a temp. gauge and pressure gauge installed but neither are working right now. They are salvaged parts out of previous SVO cars now at the graveyard, so I may need to invest in some new gauges.

I also think that the truck may need a new thermostat as it seems to be running cool. At what temp. on the dash gauge does your engine temp. usually run? What fuel pressure readings are normal for this truck?

I will take the truck out for a longer drive soon as I need to pick up some lumber for a project and see what happens when things are better heated. This truck is a farm truck and does not get a great deal of use as it is not a daily driver.

I have never had much luck with putting a flatplate after the filter and prior to the ip as when using partially hydro oils, the filter clogs quickly. Having the flatplate prior to the filter seems to solve that problem effectively.

I will do more examining of this issue this week and report back. Thanks for all the help Tim!


98 Jetta TDI with aluminim tank HotFox fuel pickup, HOH, FPHE, Coolant Heated VW Oil Cooler Filter,VegTherm, Injector Line Heaters, 6 port Pollak, and 3 port Pollak for Backflushing veg. filter
100,000 grease miles
B100 - B20 Main Tank Fuel depending on outdoor temps. SOLD

81 Benz 240D 3 Gallon purge fuel tank, Heated Pickup Stock Tank, 12V pump, HOH, Coolant Heated Filter, 16 Plate FPHE, Injector Line Heaters, 2 Greasecar Valves, Looped on Veg., Return to tank diesel.and Injector overflow return to veg. tank

91 Dodge Cummins

2010 VW TDI Sportwagon
 
Location: Vergennes, VT USA | Registered: May 16, 2003Reply With QuoteReport This Post
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Engine temperature - The stock temp guage is not marked with actual temperatures, it just shows marks at "C" and at "H" and has 4 marks in between these marks, any time this temp guage gets up to at least the first mark above "C" the veg system is warm enough to switch over (My home water filter veg filter and electric fuel pump are inside a heated ammo can that gets fed with the hottest water before it goes into the big 100 gallon veg tank internal heated fuel pickup/tank heater. The return veg water temp is usually at least 100 deg f even when everything is cold.).

The dash temp guage is showing the temp of the radiator rather than the actual block temp so it only reacts AFTER the thermostat opens. I have my veg hot water connected to the cab heater tubes that are fed with engine block water so they get hot much quicker than the radiator guage shows. In summer I can switch to veg after about 3 miles of highway speed even though it takes about 8 miles for the dash guage to get to the first mark, during cold winter temps it may take a few miles more before switching. The temp guage I have on the steel cab heater feed line usually shows between 150 - 160 deg f unless I am working the truck hard hauling upwards of 25,000 pounds gross and pulling long hills in hot weather. The fan has a viscus clutch that locks up tighter when the radiator gets hot but this only happens when the dash temp guage reaches about the 3rd center mark, you will know when it happens due to the roar from the fan, it usually only lasts a minute or two as the extra fan speed drops the radiator temp quickly even in i20 deg f Arizona/New Mexico summer temps.

Any time the temp guage on the IP inlet fuel line shows at least 80 deg f I can run on veg just fine.

I don't know what temp thermostat is in the engine, it is the original factory one and seems to do a fine job, the engine never actually overheats and by connecting to the cab heater water lines the temp of this water seems to stay pretty consistant between the 150-160 deg f point after just a few minutes of road speed driving. The hottest I have ever seen this water was around 195 deg f when the fan was locked up.

Injector pump inlet pressure - The factory book says it should be about 10 pounds. When running on diesel or cold low veg blends this is about what I see but when switching to cool veg or high blends the temp can drop down as low as 2-3 pounds, this will cause the slow idle, surging, and limit top end speed. Once the veg is heated it will also show about 10 pounds and will run fine (runs ok even at 7-8 pounds). I have run the pressure as high as 12 pounds with no problem but I would not go much higher as you run the risk of pushing the IP front shaft seal out of its seat and creating a big leak.

The Bosh "VE" IP has an internal centrifugal vane fuel feed pump directly connected to the fuel inlet, this pump creates some higher pressure to feed fuel to the metering section of the IP. The 4 cylinder version of this IP used on the older VW diesel engines does not even use an additional lift pump, the fuel is pulled from the tank using this internal pump only, same is true for some of the heavy equipment these engines are used in. My worn IP will actually pull a but of suction if I forget to turn on the electric fuel pump. It pulls enough fuel through the electric pump to idle on but the engine stalls as soon as I try to accelerate unless the electric pump is switched on (makes a nice security feature).
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post
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I have not seen the dash temp. gauge go above the first mark. It gets close when climbing the local mountain passes, but even when towing a 4,000 lb. sap tank and trailer the gauge did not hit the first mark. I suspect the truck hardly even noticed that load. This thing has some serious balls!

I got the truck out for a good drive yesterday and switched to VO after a few miles at 40-45 mph. No drop in idle or surging. I think I was just switching too soon previously. I took it for a spin on some country roads and it seems to have the same power on VO. No major difference in performance but the engine idles more quietly and the exhaust smells different of course. I shut it down on VO a couple times to do some errands and it fired right up on VO no problem. It seems like the system is working well. Now I just need to fix the temp. and pressure gauges, and finish the box in the bed around the tank.

I will post some pics soon. What a sweet truck!


98 Jetta TDI with aluminim tank HotFox fuel pickup, HOH, FPHE, Coolant Heated VW Oil Cooler Filter,VegTherm, Injector Line Heaters, 6 port Pollak, and 3 port Pollak for Backflushing veg. filter
100,000 grease miles
B100 - B20 Main Tank Fuel depending on outdoor temps. SOLD

81 Benz 240D 3 Gallon purge fuel tank, Heated Pickup Stock Tank, 12V pump, HOH, Coolant Heated Filter, 16 Plate FPHE, Injector Line Heaters, 2 Greasecar Valves, Looped on Veg., Return to tank diesel.and Injector overflow return to veg. tank

91 Dodge Cummins

2010 VW TDI Sportwagon
 
Location: Vergennes, VT USA | Registered: May 16, 2003Reply With QuoteReport This Post



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Stock temp gauge - The needle on my gauge normally sets about 1/3 of the way up between the first and second center marks unless I am really working it, it then may go to 2/3 up between the first and second center marks (unless I am REALLY working it in HOT weather, mine has a non-lockup overdrive auto trans so that adds a LOT of heat under load). May just be the difference in gauges or you may actually have a cooler thermostat, or maybe the auto trans makes that much difference? The factory gauges are likely not all that calibrated to begin with?

During the summer I start on veg once the engine is warm if I am out shopping or whatever, no problems.

After running on veg for several years now I do notice a bit less power during accelerating, not really less power, I just notice that I have to push the accelerator pedal down a bit farther til I get up to speed, I almost never mash the accelerator pedal to the floor unless I am hauling a really heavy load on hills. Also the auto trans does some weird slam shifting if I floor it from a standing start no matter the load, never have been able to get the shift adjustment points set to correct this under full throttle conditions, I have it set to shift nicely with part throttle under load but this causes it to shift at low rpms when empty, if I soft pedal it it can go into high gear at about 10 MPH 50 ft after starting to role.
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post
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Tim,

What's your blend evolved to these days, or is it about the same? Do you still do the same wash/evap WVO processing? How many miles to boast at this point?

I keep getting bogged down in hardware searches and seeing new methods emerge, so I like the relatively low-tech one-tank method that blending might offer for my warm climate - from what I see in your posts, no heat at all would be needed here, since the temps are seldom less than 70F. But I'd still want to be sure I filtered my WVO well first...yeah, there's a dusty centrifuge in my collection of still-unused hardware...

--Dave
 
Location: Honolulu | Registered: April 15, 2005Reply With QuoteReport This Post
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After several hundred miles, it now appears as though the stock lift pump is failing. It will sometimes put out 5 psi but then other times nothing. New filters and still fuel starvation symptoms with low to 0 fuel pressure. Is it common for these pumps to fail in their old age? Should I replace it with a rebuild or new pump or just throw in an electric lift pump. This is a farm truck that gets minimal use but we would like it to be dependable.

The truck will idle fine once I purge the air out, but once I step on the accelerator it loses power.


98 Jetta TDI with aluminim tank HotFox fuel pickup, HOH, FPHE, Coolant Heated VW Oil Cooler Filter,VegTherm, Injector Line Heaters, 6 port Pollak, and 3 port Pollak for Backflushing veg. filter
100,000 grease miles
B100 - B20 Main Tank Fuel depending on outdoor temps. SOLD

81 Benz 240D 3 Gallon purge fuel tank, Heated Pickup Stock Tank, 12V pump, HOH, Coolant Heated Filter, 16 Plate FPHE, Injector Line Heaters, 2 Greasecar Valves, Looped on Veg., Return to tank diesel.and Injector overflow return to veg. tank

91 Dodge Cummins

2010 VW TDI Sportwagon
 
Location: Vergennes, VT USA | Registered: May 16, 2003Reply With QuoteReport This Post
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DS - I have added a second heated fuel system that I mainly run on now, the blend there is 90% veg/5% RUG/5% diesel, this blend will stay pumpable even at below freezing temps so allows emergency cold starting on it if I have a failure on the diesel fuel side. I had to do this last winter when the filter in the cold fuel side got plugged with a high cold veg blend during a surprise cold snap.

I do run cold blends in the coldfuel side for startup and around town before total warm-up, this blend depends on weather temps, 10% "top of barrel" "will stay liquid even when cold" veg during the winter, up to a 50-60% veg blend during warm summertime temps.

I was regulary runnig on a 75% veg/15% RUG/10% diesel cold blend in summer temps just fine before adding the heated system, anything similar should work in your climate - BUT - a few days one winter that I spent in Honolulu back in the 70's got down to around freezing so you might get stranded in temps that cold.

Veg cleaning setup is still the same, water or water/baking soda wash, warm settle for a week, circulate 100 deg f warm oil through whole house water filters at least 30 times (continuously runs unattended for 2-3 days), evaporative drying while filtering by forcibly injecting the oil from the outlet of the last filter through the air and into the top of the hot oil in the filter barrel so the rising air bubbles carry off the water as vapor.

Stock lift pump - I used the original lift pump for several years before it began giving me trouble, I only noticed it because the rubber veg fuel hose I was using began "throbbing", that is, it pulsated with engine rpm. Turned out that the inlet check valve in the pump was not closing completely so fuel was first pulled into the pump from the tank and then some portion was being pushed out both to the injection pump and back to the tank. I did not then have a pressure guage on the truck but it would seem likely that the pressure into the IP was reduced. The stock Bosh VE injection pump was designed to operate without an additional pump feeding it as it has a centrifugal vane pump built into it's input (the 4-cylinder VE version on older Volkswagons does not use an additional lift pump, it pulls directly from the fuel tank, as do most of these engines used on off-road and heavy equipment), if there are minimul restrictions or distance between the fuel tank and the iP it works fine without the additional lift pump. I now use electric fuel pumps for both veg and diesel, if I forget to turn these on the engine will start and idle just fine but stalls when I try to accelerate, just as you describe, makes a fine security option.

I would go with an electric lift pump, I have had good success using Mallory gerotor pumps, a 70 G/H 4070 model for diesel and a 110 G/H 4110 for veg, the thicker fuel needs the larger flow rate pump to move enough veg for full throttle heavy pulling. I "T" the outputs of both pumps together through two steel in-line low-crack pressure (2-3 pounds) 3/8 pipe thread hydraulic check valves screwed directly into the outlet opening of the pumps, this eliminates the need for a selector valve on the input to the IP. The check valves are needeed as the pump that is not turned on will actually turn backwards and allow a reverse fuel flow due to the pressure from the running pump. The electric motors on these run a bit hot if wired directly to the vehicle 12 volts, my truck charging system actually puts 14.7 volts all the time, I run a 1 ohm or 1.5 ohm 50 watt aluminum cased power resister (about 5 bucks from Digikey.com or other electonics retailers) in-line with the 12 volt lead, this drops the volts to the motor down to between 10 to 12 volts and reduces the heating, the pump still has plenty of torque to run even at below freezing temps thick fuel (the resistor will get HOT).

If you want to go with a new stock mechanical lift pump they are usually available on Ebay for around $15-20 bucks if you search using "Cummins 6bt" or something like it rather than using "Dodge cummins" as the search term, these same first gen engines are used in all sorts of off-road and heavy equipment and they use the same lift pump as the truck, I bought two that way, one lasted a few months before leaking but it was a manufacturing defect, the input fitting mount was not thoroughly brazed ionto the main pump body, the second pump that I had bought at the same time as a backup is still on the engine as I have not yet gotten around to making up a cover plate for the pump opening in the engine block.
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post
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Thanks Tim. I have an electric fuel pump, relay and wiring anyway so i am going to install that for now so I can at least get it moving. I prefer mechanical pumps, so i will replace that when I get a new one. I figure I can leave the electric pump in there for back up.

Nothing against your setup or ideas regarding electric pumps. You seem to have a good system going. I just want to put as little as possible into this truck and would rather stick with what I got. Good quality electric fuel pumps that will handle unfiltered, heated VO aren't cheap(less than the cost of a mechanical pump for this truck) to buy or build.

It is interesting though how this fuel pump has failed. Last fall is started to act up. Additionally the shut off solenoid also was acting up so trouble shooting the two issues was interesting. Oh and the fuel pressure gauge was leaking as well. Then this spring, after sitting all winter, the truck fired right up and then went 200+ miles hauling heavy loads without issue. The last trip it started losing power and today it will start, idle, but if I try to move it it loses power and dies. Seems like classic lift pump failure. But why did it work this spring?


98 Jetta TDI with aluminim tank HotFox fuel pickup, HOH, FPHE, Coolant Heated VW Oil Cooler Filter,VegTherm, Injector Line Heaters, 6 port Pollak, and 3 port Pollak for Backflushing veg. filter
100,000 grease miles
B100 - B20 Main Tank Fuel depending on outdoor temps. SOLD

81 Benz 240D 3 Gallon purge fuel tank, Heated Pickup Stock Tank, 12V pump, HOH, Coolant Heated Filter, 16 Plate FPHE, Injector Line Heaters, 2 Greasecar Valves, Looped on Veg., Return to tank diesel.and Injector overflow return to veg. tank

91 Dodge Cummins

2010 VW TDI Sportwagon
 
Location: Vergennes, VT USA | Registered: May 16, 2003Reply With QuoteReport This Post
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I should have mentioned that the check valve failure in my stock mechanical pump was also intermittant, it would work fine some days and others the hose would pulse? Since these pumps are sealed there is no way to get to the internal check vslves, if there was they could probably just be cleaned of gunk and work just fine again. the pump never did actually totally fail but I replaced it just becsuse.

Electric pumps - Even NEW Mallory pumps sometimes sell for well under $100.00 on Ebay, I picked up a NEW 110 G/H amd a NEW marine 140 G/H Mallory pump for $50.00 each a few months back.
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post



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I put in the electric fuel pump today and...exact same symptoms continue. Will idle but loses power when in gear and moving slowly. If I step on the accelerator it will go and then die. Crank it over and it will start and idle.

The new pump is definitely pumping fuel, but when I threw on a temporary vac/pressure gauge prior to the ip it is reading low vacuum, so now I'm thinking it's just the fuel filter? But the filter only has a few hundred miles on it. Next I will change it and see what happens. If not the fuel filter then must be a mystery air leak or maybe ip?

This message has been edited. Last edited by: generalstark,


98 Jetta TDI with aluminim tank HotFox fuel pickup, HOH, FPHE, Coolant Heated VW Oil Cooler Filter,VegTherm, Injector Line Heaters, 6 port Pollak, and 3 port Pollak for Backflushing veg. filter
100,000 grease miles
B100 - B20 Main Tank Fuel depending on outdoor temps. SOLD

81 Benz 240D 3 Gallon purge fuel tank, Heated Pickup Stock Tank, 12V pump, HOH, Coolant Heated Filter, 16 Plate FPHE, Injector Line Heaters, 2 Greasecar Valves, Looped on Veg., Return to tank diesel.and Injector overflow return to veg. tank

91 Dodge Cummins

2010 VW TDI Sportwagon
 
Location: Vergennes, VT USA | Registered: May 16, 2003Reply With QuoteReport This Post
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Your in-tank intake screen is plugged partway, would be my guess. Easy check might be to blow compressed air back through the fuel line - no crazy pressure, but maybe 50psi, and with your filler cap off. Might cure it for a day, or a month, but should at least eliminate that possibility.

--Dave
 
Location: Honolulu | Registered: April 15, 2005Reply With QuoteReport This Post
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Plugging of the fuel tank intake screen was a common problem with my truck in cold [<40°F] temperatures before I started cold filtering the fuel mix before it went into the tank. The barrel of fuel mix is in the unheated fuel shed, and as temperatures drop the high melt point components drop to the bottom of the barrel. The barrel pump intake is about 6" off the bottom so I'm pushing clear mix through the 5µ filter into the tank. The Toyota LC tank has a convenient drain plug, so now I drain the tank in October to purge any 'summer mix' before cold weather operating. Adopting those two procedures eliminated the screen clogging problem, and I'm just coming out of the 2nd winter of trouble-free operation.



 
Location: coldest N.America | Registered: May 03, 2005Reply With QuoteReport This Post
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Tank screen - This screen is VERY fine, more of a plastic fabric than an actual screen, it is molded into the plastic of the snap-on section on the very bottom of the fuel tank canister. After having to drop the fuel tank twice to clean the fats off of this screen I cut it away and inserted a oiece of window screen inside the snap-on plastic unit that the screen is part of.

There is also a very restrictive plastic section in the canister, it replaces the in-tank electric fuel pump used on gas vehicles. the opening in this plastic piece is only about 1/8 inch in diameter and won't flow thick fuel at all well. I replaced it with a piece of modern fuel hose. This mod and the screen replacement are detailed (with pics) earlier in this discussion.
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post
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Thanks for the tip regarding the fuel tank screen. I just don't understand why diesel fuel systems would include this, but must just be a product of using the same components from gas fuel systems.
Just to clarify, the stock diesel tank on this truck is only being used for diesel. That said, it is possible for some VO to return to the diesel tank when switching fuel sources, and this could have partially clogged the in tank screen.

Many years ago when troubleshooting a fuel restriction in my 98TDI I put together a piece of 3/8" fuel line with an inner tube valve stem on one end. I can couple this with fuel lines to apply back pressure using a bike pump to remove restrictions when they occur. It has been very useful through the years. Well I tried backflushing the stock diesel fuel line from where it goes to steel in the engine compartment back to the tank and I did get flow and could hear bubbling in the tank but it did seem somewhat constricted. Hard to know for sure, but air was flowing. Then I hooked up my mighty vac to the same fuel line and pulled fuel through and it is moving. The vacuum would go as high as 5" before dropping as the fuel flowed through. Then, hooked it back up and the same symptoms continue. With my 3 valve fuel plumbing, it is possible to run either fuel through either filter. To try to determine if the d2 fuel filter is the issue, I switched to the VO filter while running on the d2 tank. Same symptoms.

So, either the tank screen is restricted, the fuel filters are both rectricted, or there is some other mystery issue. I am still working on tracking down a working vac/pressure gauge so I can see what is going on at the ip, but I am quite certain there is vac between the ip and fuel filters. If I open the fuel line at the filter I hear a vaccum hiss after shutting down, and the questionable gauge I do have has been showing a minor vac.

I'll keep you posted on the progress. I may just hook up a temporary 5 gallon fuel jug as a tank to confirm if the tank is the issue. Not looking forward to dropping the tank if that is necessary.


98 Jetta TDI with aluminim tank HotFox fuel pickup, HOH, FPHE, Coolant Heated VW Oil Cooler Filter,VegTherm, Injector Line Heaters, 6 port Pollak, and 3 port Pollak for Backflushing veg. filter
100,000 grease miles
B100 - B20 Main Tank Fuel depending on outdoor temps. SOLD

81 Benz 240D 3 Gallon purge fuel tank, Heated Pickup Stock Tank, 12V pump, HOH, Coolant Heated Filter, 16 Plate FPHE, Injector Line Heaters, 2 Greasecar Valves, Looped on Veg., Return to tank diesel.and Injector overflow return to veg. tank

91 Dodge Cummins

2010 VW TDI Sportwagon
 
Location: Vergennes, VT USA | Registered: May 16, 2003Reply With QuoteReport This Post
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Well it turns out that my assumption that the fuel selector valve was working was incorrect. The Greasecar valve we installed in the truck appears to no longer be working after about 400 miles. I think I am going to go manual valves on this truck. Anyway the truck is running on the VO tank and VO fuel filter with a 50/50 d2/VO blend in the tank. So, the problem was either a clogged diesel filter or the diesel tank screen is restricted. Ordered a diesel filter so we'll see if that does it.


98 Jetta TDI with aluminim tank HotFox fuel pickup, HOH, FPHE, Coolant Heated VW Oil Cooler Filter,VegTherm, Injector Line Heaters, 6 port Pollak, and 3 port Pollak for Backflushing veg. filter
100,000 grease miles
B100 - B20 Main Tank Fuel depending on outdoor temps. SOLD

81 Benz 240D 3 Gallon purge fuel tank, Heated Pickup Stock Tank, 12V pump, HOH, Coolant Heated Filter, 16 Plate FPHE, Injector Line Heaters, 2 Greasecar Valves, Looped on Veg., Return to tank diesel.and Injector overflow return to veg. tank

91 Dodge Cummins

2010 VW TDI Sportwagon
 
Location: Vergennes, VT USA | Registered: May 16, 2003Reply With QuoteReport This Post



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