wvo power problem

[don b]

I have a 85 300d, I have a 2 tank greasecar system installed. i was lacking power and felt like there was air in the lines. It runs perfect on diesel, and will rev up over 4k with no missing on veg. when i put it in gear and drive it down the road, it gets up around 3k and starts clugging out. I don't understand why it will rev up in park and have no loss of power, but when i'm going down the road it will lose power. I put a brand new vegi filter on, and no difference. could this be something with tranny not letting it get enough fuel? I could see air bubbles coming up out of the red line before the vegi filter. i don't understand how air could be coming out of that line, it runs directly from the vegi tank. thanks any help would be greatly appreciated, i'm st my wits end! >

[jt20]

under load, you have turbo boost. This enriches the fuel input more than no-load revving in neutral or park. Thus, a higher demand for fuel flow.

Recently, there was another member here with a very similar problem. Try searching.

His engine was not a turbo. He was able to improve his fuel supply by fitting a lift pump from a turbo engine onto his injection pump.

the turbo engines have a stronger piston spring in the lift pump. And, if I remember correctly, the Greasecar system uses a sucking force to pull the fuel through the filters...

...this is a poor design.

The lift pump should be PUSHING the fuel through the filters.

Depending on the spring to do all the pumping through the restrictions is weak. The camshaft of the Injection pump should carry this load and it only occurs on the pressure side of the lift pump.

Since you do not have the option of an upgrade to a stronger lift pump, you should consider re-evaluating every connection on your system and maybe re-arranging your bypass and control valves.


disclamer: I do not have a veg system, some terminology may be flawed

[don b]

should i try to get a fuel pump inbetween the tank and the filter? this way the fuel will be pushed through the filters not pulled? is this what you are saying?

[Biodiesel300TD]

An auxiliary fuel pump will reduce the work your lift pump and IP have to do. I have one right after my veg filter, this way the veg is being pulled through the filter, and the lift pump and IP don't have to to any more work than normal. I'd also check all the fuel connections just to ensure you don't have any air leaks. Also how's your heat situation? If you are laking enough heat your VO may not burn completely and cause starvation like issues at higher RPM.

[btrapr]

My 2cents

You posted____I could see air bubbles coming up out of the red line before the vegi filter.

***Revs to 3K on oil tells me that the air is causing a flow problem...limit the FUEL results in a LOSS of POWER/REVS/ETC...the pump is trying to pull the oil BUT the AIR coming in limits its sucking power! If your cure this I feel your troubles will go away_ IF you do not believe me take a drinking straw poke a needle straight thru it a couple of time, make sure the holes are on both sides and open...4 holes...place the straw in a glass of water with the holes in the open air___and try drinking and you will see what I am talking about.

If nothing else get enough hose to bypass your existing one from the tank forward, hook it up and see what happens

*You need to make sure your line does not have a hole in it, check the clamps, and look for any place where it is mounted to the vehicle or anything that could be rubbing...sucking air will limit the lift pumps ability to pull the oil to the engine where it needs to be. Is your tank vented? if it is sealed or the vent is plugged it could cause a vacuum which will pull the grease back towards the tank?

*Second what is your oil temp? it needs to be 100 coming forward so it is thin enough for the pump to get it moving...then 130-160 to the injectors...I designed and had some friends weld my system...I had a heating system at the tank that I could regulate "Ballpark" the oil temp before it went up front...My first long trip 150 miles in 30 degree weather---the oil was 154 coming forward...I cut it down going home

*Lift pump spring should be 26mm in length I think...do a search...I pulled mine and it was 24mm so I gave it a little pull and got it the 26mm...

*I agree with a second pump...
I am getting ready to do my 2nd WVO conv on a 300SD...sold my 300td...I am going to try a 1991 Chevy truck 6.2 diesel electric fuel pump I think they are around $45 from my local O'reily's, Auto Zone, or Advance

[Fattyman]

Another good reason to have an extra fuel pump (boost pump). You will be able to spot any leaks if the pump is pushing the fuel instead of pulling it. It will also make the pump work less and last longer. You have a fuel delivery issue on your vegi side. If you are running the Greasecar spare tire round tank you need the boost pump as that tank sits lower than the IP and your stock lift pump cannot deliver the fuel as needed. Get a pump and your problem will be solved. Have Fun.

[don b]

i think you're onto my problem, i replaced clear strong rubber lines with flemsy black fuel lines. i think when the turbo kicks in, the extra suction is collapsing the fuel line, and cutting off my fuel to the engine. thank goodness i'm so cheap that i kept the old lines and threw them in a bucket! I'm gonna try putting them back on tom. can anyone tell me how to install and extra fuel pump? do i just go to autozone and say hey i need any fuel pump? are there special ones that fit anything that you can get? can i gey one at a junkyard? How would i hook up the juice to it? Possibly find an ignition wire or to the fuse box? thanks!

[ah-kay]

Why you need extra fuel pump? It is one more point of failure to an already complicated 2 tanks system. The viscosity of the WVO will be similar to diesel when at temperature.

I would try to resolve the power issue in this manner.

1) Run the car up to temperature with diesel or WVO.
2) Hook up a gallon of WVO/SVO to the primary filter and put the return in the gallon container.
3) Run the car with the gallon WVO and see whether you have power.
4) This is similar to a diesel purge setup and take all your greasecar two tank setup out of the equation. I bet the car would run fine.
5) If you still don't have power then it is the filters, engine or IP.

I suspect you have a leak and is sucking air.

Good luck.

[tigerlxxv]

Seems to me, if you absolutely HAD to add an extra pump, a really smart way to do it would be to use a pump that works fine producing negative pressure. situate this pump AFTER the aux filters that were added for the veg fuel supply, and have it run into a small 1 or 2 quart accumulator tank. The accumulator could be placed up front in the area of the windshield washer fluid reservoir, with a fitting to run down to the primary filter and on to the IP. This means the lift pump has negligible backpressure to draw against, and has two other advantages. the accumulator tank could be fitted with a sediment/water purge valve at the bottom, AND could be used as a fuel preheat chamber, for those so inclined. This may be redundant, as it's been a while since I looked at the various WVO/SVO kits on the market. but there's another $0.02 on the heap. Good luck getting it all straight, and may your motoring be smooth.