were these vegetable oil systems set up to avoid the two biggest dangers of running wvo ??

coking and cavitation

coking of the injectors and combustion chambers is caused by injecting straight vegetable oil at temperatures that are too low...
it is believed that the vegetable oil should be as hot as 160-180F before it hits the injectors in order to burn properly and cleanly...

cavitation in the injection pump is cause by using vegetable oil that has water suspended in it... (a rough description follows since i am not an expert on cavitation)
when the vegetable oil (and water) enter the high pressure environment inside the ip, the water is transformed to steam and creates a cavity into which the fuel rushes. the forces involved are similar to a small explosion and over time it causes erosion of the highly polished surfaces inside the injection pump. eventually the pump can be destroyed this way...
a water seperator type filter is not enough to remove water from vegetable oil, since it is suspended differently in this fuel than in diesel...
to avoid cavitation you must dewater your vegetable oil by letting it settle and then heating it at a low temperature (around 100F i believe) for several hours...

search (coking, cavitation, dewater) on the vegetable oil forums for more info regarding these problems...

and please follow up and let us know the final diagnosis so we can learn from your ordeal

the last post seems like it might be the answer. On the other hand is there anyway that vo would help clog up a catalytic converter or somehting else in the exhaust system. This sounds like a stupid question to me, but most other ideas seem to have been exhausted.

test your UCO (used cooking oil) for water. Try the fry pan test and see if you get bubbles. More details on the test can be found at the Maui Green infopop site.

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"If anyone knows other lessons I need to learn, please tell me. I'm tired of learning them the hard way".
by JerryBro

The Glow Plug Wait: This waiting period is a moment of silence to pay honor to Rudolph Diesel. The longer you own your diesel the more honor you will give him". by SD Blue

My normal daily life; either SNAFUed- Situation Normal... All Fouled Up, or FUBARed- Fouled Up Beyond All Repair

62 UNIMOG Camper w/617 Turbo, 85 300SD daily driver- both powered by blended UCO fuels

Could not have said it better myself....

Did you wait till the engine was at full operating temp before you switched to WVO? This is a common problem when you find out you can save money by running WVO, and also not purging long enough and still having WVO in the injector lines, then when you start up your putting cold VO in a cold cylinder = coking...

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1987 MB 300TD, 245,000 miles running great, converted to WVO.
1996 Ford F350 2WD,PSD,CC,DRW custom conversion, soon to run on WVO.
2003 Toyota Matrix,4WD (wifes)

I would check the glowplugs again. I see that you had a shop replace them all, but lon experience has shown that a new plug is about as likely to fail as an old one at any given time. All it takes is one out and with a rough running diesel already and a little cool weather it will not start.
Just pull the glow plugs and clamp them in a vice and then ground the vice and touch the end with 12v. Will either get red hot or will do nothing.

Well, I'll give it my shot. I'd be concerned about the hydrogenated oil, but I don't think there is any wax in it, unless you mixed it with diesel. Is the wvo returning to the diesel tank? That's where you may get wax.

I have run 7000 miles on completely unheated wvo with only minor injector coking issues. Injector coking is more likely to be from shutting down on wvo than starting on it as the oil polymerizes on the wet tip. Ring land coking is more likely to be caused by starting on cold wvo.

But, if you are not getting even a quiver from starting fluid, it would seem like either:
a) there is an obstruction in the intake somewhere
b) the valve timing is way off
c) there is no compression at all.

When cranking the engine, see if the exhaust is pulsing air out. Using starter fluid, you ought to be able to smell it at the exhaust if it doesn't get burned.

A compression test will likely point you in the right direction.

Good luck and keep us posted.

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1984 300Sd 210k

Former cars:
1984 300D 445k (!!) (Strider) Original (and not rebuilt) engine and transmission. Currently running on V80 ( 80% vegetable oil, 20% petroleum products). Actually not, taking a WVO break.
1993 300d 2.5 275k. Current 120/day commuter
1981 300SD 188k (Hans) Killed by a deer

Just wanted to say thanks again for all the ideas. I'll smell my exhaust and will get the compression test. It will take a couple of days since the local shop is pretty booked and I am not equipped to do this myself.

By the way, I took the air cleaner off to eliminate it as a source of failure. Right now the only thing left of the intake is the U-piece right in front of the turbo.

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84 300SD with Greasecar vegetable oil kit. Boston, MA

It almost has to be fuel flow blockage somewhere (Unless it's a complete and total IP failure). I'd fly it to an equatorial region where the high ambient temps would liquify even the most stubborn Wendy's pork grease. If the shipping costs are too high, find a really old lady in the neighborhood who keeps her thermostat up at 95 and park it in her living room for a day.

Seriously, if it's a blockage, you could take a container of fresh diesel with a little kero in it, and run it direct to the lift pump with a short length of fuel hose, bypassing your own tank and lines. Unhook your return line and see if you get anything. If not, start backwards, clogged return lines from injectors? Sounds like you would have pulled them to check injectors. Do you get fuel from injector lines themselves if loose from injector? I see you replaced the glow plugs. Do they get current for a while and heat up?

Obviously you might have timing issues, issues related to damage from VO, but I'm inclined to think you should still be able to get it to start, or make noise....
Ben

I would try to tow the car, hopefully you dont have automatic transmission.
If you first get it warm in a garage this would help a lot.

This summer I replaced the engine in my W110 and had a lot of trouble starting it, drained 3 batteries.
I also tried startgas but I got only one stroke with ignition.
Then I called a friend and he said I should try to tow it, he said even in the winter (northern Sweden) he had started his old 300d this way, so I did the same and 200 meters later the engine was running and has been since.
I checked and saw fuel coming on all injectors on this engine.

if you don't have it hot enough, aro 160 deg, or you cold start on cold wvo, you are asking for problems.

if the oil is sticky then animal fats are in the oil. i recently got oil from a place and i discovered that there is fat floating around in it. its tieing up 6 buckets right now until i get it back to the drum it came from.

keep the wvo hot important. try a veggietherm before the primary.

what temp does the wvo tank read>? not the engine temp guage but the wvo tank guage.

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currently
[1981 300 td tdidi 165500 dark brown/palamino-Brownie-mine-3k miles of ownership
1983 240d 162+++ Anthricite grey w/ henna red interior and hella lights-wifes car-Red

the above two cars are for sale
and can be seen on the cars for sale thread here. pix also available.


240d-144+ Manilla Yellow w/ palmino interior-greasecar kit-Blondie-the college kids car

23" gt 21 speed still on original tires-still got the nubs
21" khs tandem

For a diesel engine to start from cold, it needs:
- Compression - this has been mentioned before, but if the oil was too cool, and coking of the ring lands was occurring, this will drop engine compression rapidly. A squirt of oil into the cylinder may improve compression figures.
- Air - If the valves are working and the air cleaner is not totally blocked (or in your case - disconnected) your engine will suck air into the cylinders.
- Fuel - Fuel of a high enough cetane, injected at the right time, into the hot air (heat of comprression) in the cylinder (or prechamber) will burn and the engine will fire.

Possible fail to start causes:
- Cylinder air temperature too low. Caused by dead GP or low compression/ valve leaks or Cam failure
- Lack of Fuel - a Fuel restriction would need to be total, to cause this, as the idle setting delivers only a minute volume of fuel to the injector.
Air in the fuel is a strong possibility.
- Lack of Fuel - damage to the IP caused by corrosion. Water kills IPs. If your oil is not guaranteed dry and if you do not have a water removal regieme and a water trap in the fuel system, after the fuel heater, you are just waiting for an IP failure.
- Incorrect Injection timing - generally would only happen if the timing chain were incorrectly set, skipped a tooth, or broke.

Failure to fire on starting fluid points strongly to failure to create adequate compression.
A compression test is the first thing you need to do. As others have already advised you. If there is any waiting to be done, you can remove of the rocker (cam) cover to confirm that the cam is intact ad rtotating with the engine. The valve clearances should be checked to ensure that they are within specification, to assist with the diagnoisis.

If low compression is found it will be on all cylinders (no firing AT ALL on starting fluid). Put some oil into each cylinder to determine if this is due to rings (compression will restore when the oil is added)

Please keep us informed of your progress.

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Tony from West Oz.
Fatmobile 3 84 300D 295kkm Silver grey/Blue int. 2 tank WVO - Recipient of TurboDesel engine.
Josephine '82 300D 390kkm White/Palamino int.
Elizabeth '81 280E, sporting a '79 300D engine.
Lucille '87 W124 300D non-turbo 6 cylinder OM603, Pearl Grey with light grey interior


Various parts cars including 280E, 230C & 300D in various states of disassembly.

Tony - good post, much more specific than mine....
ben

Mike,

If your glow plugs are working properly and you tried to use spray start mostly the engine will NOT start. It will buck and try to kick back as the glow plugs ignite the ether before the piston reaches TDC. Do this a few times and you run the chance of bending a rod. To start a Diesel equipped with GPs using ether you must disconnect your GP circuit.

If you did not get this kick back when using ether with out disconnecting your glow plugs then the chances are good that your GPs are not working.

kip, interesting observation. Before the engine stopped running AAA started it once with starting fluid and the noises the engine made were probably the kick-back you are referring to. I have no plans to try starting fluid again at this point.

Tony, I will try the oil should I find low compression. Would that be regular engine oil? And how much is a good amount.

The issue I am having now is that I discovered that nobody has a compression tester for a diesel or they don't have an adapter for a Mercedes or both. I found one on Toolsource.com but the Mercedes adapter is backordered and only expected to come in mid-December.

Does anybody have a good source for a compression tester (including the correct adapter)? I would prefer the adapter for the glow plugs since they seem generally easier to remove than the injectors. That one seems more difficult to find than the injector adapter.

But just in case I have to pull the injectors, what is a good way to get the injectors out? I saw that Samstag Sales sells a special socket to remove the injectors (it has cut-outs for the leak line pipes). Is that necessary or advisable or can an injector be pulled safely with something like a crow foot?

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84 300SD with Greasecar vegetable oil kit. Boston, MA

you don't need a special socket. I bought a 27 mm deep socket that works great and also fits the front crank bolt. Less than $10 from a local parts store. Needs to be about 55 mm deep inside, that's all.

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.