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W124 E300 diesel... Poor diesel? Vegi oil?! How strong are the injection pumps?

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by joe1972, Oct 11, 2009.

  1. joe1972

    joe1972 Senior Member

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    Hi again all.

    I've been loggin on and following the multiple starting issues on this forum with interest, now that the cold/wet season in the UK as starting.

    Unfortunately, my diesel mb now has an issue, or maybe just a hiccup.....

    At motorway type speeds I was getting poor throttle response, and occasional coughs from the engine. Having read similar experiences on here, I've set to and replaced the main fuel filter. Sure enough the filter was full of bits and generally in a bad state. When I bought the car not so long ago it was obvious from the smell when running that the former owner had been running it on biodiesel or vegi oil, so my thoughts are the crap in the filter is the legacy from this.

    So now I have a car with a fresh fuel filter.......but it won't start!?
    I've been careful to drag fresh fuel from the tank, and don't think I have an air lock from tank to filter.

    However, from bad Vauxhall diesel experiences I'm feeling something is coming back to haunt me......

    Has the diesel injection pump died? How strong are they? The GM pumps were renowned not to be strong enough for the vegi fans, but much has been aired on how good MB cars are with alternative fuels. I'd rather run mine on straight diesel, particularly as it looks unmodified, but worried that the history of the previous owner running the car on potentially hi viscosity bio/vegi oil has damaged something, and over time of vegi abuse it's finally given up?

    I would value some experience and thoughts? and pointers to get the car started!

    thanks
     
    Last edited: Oct 11, 2009
  2. turbopete

    turbopete Senior Member

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    Your Mercedes:
    2010 '60' Ford Mondeo 2.0TDCi Zetec (sorry)
    i have an 210 e300 turbodiesel. i believe that may have been run on vegi oil or similar in the past and that may be the cause of my poor starting/non start when hot. it can dry out and ruin the standard seals. the modification is to fit modified seals, i believe, having read many articles on the internet. speaking from experience with my car, they are an absolute pain to bleed. if i end up getting my pump rebuilt i may enquire about upgraded seals so i can then try to get waste oil from the local chippy etc, filter it and rum my car for (almost) free
     
  3. simon_wall69

    simon_wall69 Senior Member

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    Make sure the new filter is full before filling and that you have a good seal and then it takes ages of cranking to finally start. May well be whole battery.

    My old E300 did 30,000 miles or so on veg with no problems apart from o rings on the fuel lines going - this could have happened to you and you have air in the lines. Very common.

    The pumps generally last - my previous car had done over 400,000 miles and the pump still pumped veg oil.
     
    Last edited: Oct 11, 2009
  4. roadhog

    roadhog Senior Member

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    Your Mercedes:
    W124 300D x2, C124 300
    I've been running mine on SVO for the past 43k miles in varying degrees of mix, quite often 100%. My car is not modified in any way and other than more regular fuel filter changes at first, I have not had any problems.

    Two things spring to mind, did you replace the inline pre-filter at the same time? If you could see bits in the main filter (I've never seen that on mine) the chances are that the little plastic one is blocked too.
    Also it is remotely possible that the strainer in the tank may be gunked up. This would be due to the veg oil cleaning your tank of all the diesel residue and not the other way round. Veg oil is quite a good detergent and will make a lovely job of your tank. :) The more serious Veg oil fraternity in Germany recommend removal of the tank strainer altogether but I've not felt the need to go that far.

    I have had one problem when I changed the fuel filters once and the car wouldn't start. I put the old filter back and it did so went and got the new one changed and it was fine.

    AFAIK, the injector pumps are as strong as they come and, being inline rather than rotary, very well suited for alternative fuel. Vauxhall pumps were/are rotary I believe.

    The choice of fuel for your car is obviously yours but you have the most suitable car for running veg oil there and at (currently) 35 ppl saving I know which I'll continue to use. :)
     
  5. roadhog

    roadhog Senior Member

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    Sorry TP, that is complete myth IMHO. You need to look elsewhere for blame
    for your starting problems.
    The reason the seal may start to leak is that the veg oil softens them up after years of being dried out. AFAIK there are no modified seals specifically for veg oil use and people just replace with new standard items. Whether they have been modified for other reasons or not I don't know.
     
  6. turbopete

    turbopete Senior Member

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    it was something i read on a pump reconditioners website that said there were modified (different material) seals that were better suited to veg oil useage than the standard rubber items. i know nothing about the seals so can only judge from what i read. if i can find a cheap/free source of waste oil though (which may be where the modified seals come in) i would seriously consider it as fuel prices are getting out of hand now!
     
  7. roadhog

    roadhog Senior Member

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    Your Mercedes:
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    I run SVO rather than WVO as the latter is a lot harder to get hold of than is commonly believed. It's still a fair saving though. :)
     
  8. turbopete

    turbopete Senior Member

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    i have a mate that deals in cooking oil though if i cant get it from the local chippy etc. he used to make biodiesel but he doesnt bother much now as at least 1 of his vans wont run on it as its a euro4 engine
     
  9. simon_wall69

    simon_wall69 Senior Member

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    Be careful of the local chippy route. Most don't cook in veg oil - they use this white lardy type stuff that is very, very viscous when cold.

    As RH said, WVO is hard to get as there are many of us going down the veg oil route now.
     
  10. OP
    joe1972

    joe1972 Senior Member

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    Well, as an update. I've taken a second look around the fuel filter. I think I may have stumbled across an air leak where the fuel feed goes into the top part of the assembly (the part the filter screws into from underneath). There's three plastic push fit lines going into this part, and from what I have assumed is the one on the far left (offside), is the feed. The plastic was a very loose fit. I've scraped off the silicone sealant that I found all over it (not spotted before, as it's hidden well by that top plate!:roll:).....For now I've wrapped the end of the plastic in PTFE tape to make a tighter, hopefully airtight, seal.
    The car now splutters as though it's going to start (which it didnt before).....I just left it for the battery recharge. With a bit of luck a fresh charge, then a good long crank will be enough to start?! (fingers crossed)

    I stand corrected if I've got any of this wrong, and welcome further ideas and comment.

    Thanks for the comments so far, and hats off to you guys for running vegi oil, but I'm going to stick to diesel for the time being.
     
  11. roadhog

    roadhog Senior Member

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    Your Mercedes:
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    Did you check the inline filter?
     
  12. OP
    joe1972

    joe1972 Senior Member

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    is this the one towards the rear of the car next to the priming pump?
    I've not investigated that end of the car yet. I take it those filters are mb parts only items, as the motor facter wasnt listing any other than the main screw on one Ive just replaced
     
  13. roadhog

    roadhog Senior Member

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    Your Mercedes:
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    It's the little plastic one hidden underneath the air filter box.
     
  14. OP
    joe1972

    joe1972 Senior Member

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    my airfilter box isnt sitting on top of the engine, its directly behind the offside headlight. (l reg 3litre turbo diesel) The top of the engine is dominated by the huge manifold assembly. The fuel line looks to routed under this manifold assembly?
     
  15. roadhog

    roadhog Senior Member

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    Your Mercedes:
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    Sorry, didn't realise it was the racing version. In that case I've no idea where the pre-filter lives or even whether there is one at all.

    If you've still got the old filter you could try and refit it to see if the car starts, it worked for me once and there was no obvious defect with the filter I'd fitted. If the starting problem only happened after you changed the filter, chances are it's something you disturbed whilst doing the job.
     
  16. OP
    joe1972

    joe1972 Senior Member

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    racing version??.....it seems quite slow compared to the 190e ;)
    Even though I've not got the car started yet, judging from the comments above I'm feeling more relieved it's unlikely to be a broken injection pump, which I was getting worried about.(on past 'expensive' experience)
    I tried refitting the old filter...unfortunately to no avail, so the new one has gone back on.
    Yes, I think you are right. I must have disturbed something, and I suspect an airlock or leak somewhere now
     
    Last edited: Oct 11, 2009
  17. roadhog

    roadhog Senior Member

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    I would have thought it unlikely to be the pump. Do post up when you eventually cure this though.
     
  18. OP
    joe1972

    joe1972 Senior Member

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    will do. (hopefully when it's running again soon)
     
  19. Number_Cruncher

    Number_Cruncher Senior Member

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    Your Mercedes:
    1995 W124 E300D TE
    If there was silicone sealer around the fuel pipes, then the previous owner was a complete cowboy - who knows what you're going to find in your fuel system.

    I would buy and fit a set of the low pressure fuel pipes from MB - they are not expensive, and come with new O ring seals on the end. If you remove the two bolts low down on the left end of the filter housing, you should be able to move the housing aside and get to the pipe fittings on the injector pump - this avoids the need to take the inlet manifold off.

    Check the routing of the pipes here;

    http://www.detali.ru/cat/oem_mb2.as...GM=717.433&CT=M&cat=19T&SID=07&SGR=120&SGN=04

    The upper diagram is for W124s - check to see if the previous owner has replaced the fuel shut off tap with a simple bolt as per the W210 installation, it's a common bodge which should be rectified ASAP.

    The pre-filter is to the left of the large, secondary, filter on the filter housing, it is held by a M6 bolt [10mm hex], and has a large O ring seal which sometimes leaks air into the fuel. The prefilter is a gauze filter, and you can wash it out and re-use it, although new ones aren't expensive.

    Try to avoid the use of sealers and PTFE in the fuel system, because you do not want fragments of gunk and PTFE floating around inside the system, and blocking up the small holes in and around the pumping elements.

    Those who insist upon ruining their fuel systems and engines with comedy fuel should consider replacing the seals with Viton, which resists chemical attack better.

    Hint: These engines were designed and developed to burn,..... DIESEL!!
     
  20. roadhog

    roadhog Senior Member

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    Not wishing to start a lengthy debate but if you go back in history long enough (or ask Malcolm) Rudolph Diesel's engine originally ran on peanut oil. The MB engine designation to this day is OM which stands for Oel Motor. They run perfectly fine on veg oil and it does wonders for the emissions test come MOT time. Comedy fuel indeed! :D
     

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