Very Strange Mercedes 1983 SD Problem Any Help Appreciated

9 replies [Last post]
sykess1's picture
Joined: 11/28/2010

Hi All,
I have been happily running a Greasecar system in my 83' MBZ 300SD for 5 years now without a single problem until recently.
When I leave for work in the morning I have a two mile hill to go up as soon as I leave the house.  About halfway up the hill while still running my co-pilot in manual on diesel the car stalls like it's out of fuel.  I then sit for the next 20 minutes cranking it trying to get it going again while feathering the accelerator.  I finally get it running again and then it's fine all day long.  That includes on veggie oil, diesel, uphill, downhill, 70mph on the freeway. In other words it runs great and I can't make it have the problem again until the next morning going up that first hill again.  Keep in mind that this happens on diesel or veggie oil.  At first I thought it was a veggie oil problem so that's why I started to just go up the hill on diesel and keep the co-pilot in manual to no avail.
The Greasecar system was installed 5 years ago by Beach Benz in Huntington Beach Ca. (official installer)  They recently told me they will not touch a Greasecar system again because of all the people not filtering their oil properly and holding Beach Benz responsible for engine damage.  So this puts me out of luck for a mechanic.  I have had every filter changed that can be changed by other MBZ shops including the one in the diesel tank with no success for this stalling problem. I can also assure you that my WVO is very clean and I filter it very well with no water present in it.  (this doesn't matter because it stalls on diesel)   I also change the big Greasecar filter regularly.  Sometimes after as little as 300 miles just to see if it helps but it doesn't.
Every MBZ mechanic around here says if I disconnect the Greasecar system my problems will be over but they will not work on the system.
 I refuse to drive a polluting diesel car without veggie oil!
I am not inclined to work on the car myself other than changing the big filter  so I need a mechanic in the Los Angeles area that can help me.  Any ideas?  Thanks in advance for any help.
Cheers,   Steve

1984George's picture
Joined: 09/28/2009

If your system is 5 years old have the hoses ever been replaced? Air could be getting sucked in somewhere and making it stall, although you are right it's strange that it runs fine all day afterward.
I'm a little bit mechanically inclined with the old Benz's, not a lot. We also have a group down here in San Diego that meets every month to talk WVO. Virtually everyone in the group has a Benz and we like to trouble shoot stuff if you ever wanted to come down.
If your problem isn't air it could be something related to the injection pump shut off valve just engaging at that given moment, or another stock benz problem, but I would still bet it's an easy fix. ]
I hope that helps.


'03 Jetta TDI

sykess1's picture
Joined: 11/28/2010

Hi Daren,
Thanks so much for your reply.  I hope you had a nice Thanksgiving.   I think the larger problem here is the fact that I just don't have time to deal with this on my own. I really just need a local mechanic that will do the work and not insist on removing the Greasecar system.
As a side note, this problem never happens at all if I drive around for awhile on level ground before going up the hill.  In other words, as long as the car is fully warmed up the stalling does not happen.  However, I've been driving up this same hill for the past 5 years with no problem until the last couple of months.  Weird Huh?
Cheers,   Steve

1991 Jetta SVO's picture
Joined: 05/21/2004

It is air in the system probably from a 5 year old hose. It probably gets there when you flush the system and then let it sit. That is why it is only in the morning. It is a very minor air leak but once the air is out the fuel system it seals the air leak. I have been using all Pex line like in your greasecar fuel line HIH. This seals like the factory mercedes line. But I have only used it this way for a year I can not tell you what happens after 5 years.
I suggest you buy some fuel line and change the hoses yourself. It will be good for you. Just take one off cut one the same size and put it back on. Then repeat until they are all changed. A knife and a screwdriver is all you probably will need. If you can not figure this out......


Two grease cars: First--2006 Jeep Liberty CRD it is nice and new and runs perfect on the grease with a custom spare tire tank 2nd frame mounted tank for a total grease volume of about 27 gallons, two greasecar valves, FPHE, and Injector Line heater mounted on the Common Rail. I have a spare tire cover that goes over the tank in the picture. Second Vehicle is a 2005 Mercedes E320 CDI with 3 greasecar valves, a 36 gallon custom tank in trunk, Comon Rail Heater and a Raw Power fuel pump.  I use all PEX line and flare fittings with pushlocks.

solarbus's picture
Joined: 11/02/2011

I agree is sounds like air in the fuel line.  This can be verified by temporarily placing a glass in-line fuel filter in a convenient place where you can see it, somewhere near the IP pump.  You can pick up these glass filters for $10 at any auto parts store and you can take the metal mesh filter out and just use the housing so you can see the fuel.  They look like this:

 Next time you go up the hill, look at the glass.  I would bet it has air instead of fuel in it.  Then when you get it running again, look at the glass; I bet it has fuel.    This will verify you have air in your system.  once you determine that's the problem, you can put a handheld (Mityvac) vacuum pump right where you had the glass filter and a pincher or clamp on the fuel line right near the tank.  Then suck with the vacuum pump and listen very carefully; you should be able to follow your ears to the leak.
I had an 85 benz a while ago and the metal sections of fuel line between the tank (rear) and engine started to rot out before the hoses that were put in for the veggie system did.  I could hear the sucking sound from those metal lines.  they're kinda hard to get to, but I yanked them all and replaced them with fuel hose and was back in business.
It's possible you have a small leak in the line, small enough so that it doesn't bother anything when you're driving (but it could be putting tiny bubbles of air into your fuel, which is not good, even though it seems to be running OK.  when you let it sit for a while, a tiny hole like that could allow a bunch of air to get in and form a bubble in your air line.  I'm not sure exactly how it could work but I could see the bubble responding differently when you go up a hill.
fyi, having that glass window into your fuel line is a great thing... I would keep it there permanently and have done that in some cars before, but I find that they eventually start to leak and they are poorly designed for permanent use.
One other thing... rather than killing your starter and battery when this happens, you *might* be able to purge the air from the line with the little pump that is bult into your car.  It's been a while but I'm pretty sure I remember there is a little hand pump right near your IP pump that has a white twisty top to it. I think it's there to purge air when you change the fuel filter.  Anyway, if you turn the little white top, this will allow you to pull back on a plunger, which sucks on the fuel line.  If you push and pull on the plunger a few times, you might purge the air bubble without putting extra wear on your starter.  Make sure you push the plunger back in and turn it back tightly.  I've seen those little plunger thingy's get loose and cause problems.
good luck.

bigjerel's picture
Joined: 02/02/2011

Were you able to figure this out?  What fixed your issue?  Please share...  :)

RenedeLathauwer's picture
Joined: 08/14/2005

I personally know a very good diesel mechanic (specializes in turbos and computer controll systems)  located in Wilmington.  He services a few greasers in the area.  310.951.1485
North Lakme Ave. Wilmington.  Mention my name to Fernando.


slatemd's picture
Joined: 11/26/2007



The future of America is easy to perceive;  Just visit Mexico or South Africa!

victorskunk's picture
Joined: 03/30/2012

sounds to me like you have a weak fuel pump, also make sure the the injector lifters in your injector pump is not leaking...... the o-rings go bad and you lose fuel and pressure.
because it is happening to both fuels, it is the fuel pump
hope the two filters for diesel and the veggie one are separate

Renntag's picture
Joined: 10/21/2009

As about every post above suggests, "Air in the system".  I have worked through these same issues. I doubt a pump is your problem as they dont have the same symptoms. 
Somewhere an old hose is allowing air in, but only at full load (ie trying to climb that hill). 
To test, get a clear filter of some sort, even a section of clear hose will work in a pinch. It wont last indefinitely unless it is intended for fuel. (tygothane will hold up).
When I have had to diagnose similar issue, I got a section of cheap clear hose from the hardware store and manipulated the system to see small air bubbles flooding the fuel stream. Bingo !  Now to search the source. 
Best of luck and PLEASE report back with details of what you did and found to help those in the future.