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Thread: Blend Startup

  1. #1
    Join Date
    Oct 2006
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    Newcastle
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    324

    Blend Startup

    I have a new 1980 300D that goes like a rocket on diesel. I have just started using a blend of approx 20% ulp and wvo. It runs great on the mix but is rough on startup on a cold morning. It is now just starting to stumble on some warm startups when sitting for 10 mins or more. On startup after a few revs it is purring.

    Will the rough start cause long term issues. Is the rough sometimes startup indicating what?
    Last edited by PeterAC; 14th September 2011 at 10:17 AM.

  2. #2
    Join Date
    Apr 2006
    Location
    New Zealand
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    Re: Blend Startup

    This is the subject of some quite spirited debate on this forum with opinions and experiences varying considerably.
    I believe the issue stems from the ulp overheating and creating bubbles, vapourizing, frothiness, airlock or whatever term one wants to give it.
    One solution is reduce (or eliminate) the ulp content in favour of other blending substitutes.
    ULP has the bonus of being very "viscocity reducing" but has the downside of being volatile. In monitoring of injector line temps in my Hiace, I can report that the issue starts around 40'C and upward. The effects are relevant to ambient temps, blend ratio and journey duration.

    Short glow plug life is another issue that a number of vege vehicles suffer from.
    It would be worth checking them as starting will be poor if some have burnt out. Blending has reduced the incidence of burn out of the G.P.'s for me as has the fitting of a momentary push button switch to interrupt the trigger circuit of the G.P. timer.

  3. #3
    Join Date
    Sep 2005
    Location
    WA
    Posts
    4,187

    Re: Blend Startup

    It may be that you have too much petrol in your blend.
    Try adding more veggie oil to the tank and see what difference it makes after more driving to mix the oil into the blend.

    I start my 300D easily when warm at any time of year on straight veggie oil.
    Cold starts on veggie oil are possible any time of year (with good GPs) by leaving the GPs on until the indicator lights on the dash brighten up again (indicating the end of the glow time).
    If using a blend, I would suggest no more than 10% ULP when daytime temperatures are above 20C.

    Regards,
    Tony
    Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

    Current Vehicles in stable:
    '06 Musso Sports Crew Cab. Running on used cooking oil with 5% to 10% misfuel.
    '2014 Toyota Prius (on ULP)


    Previous Vehicles:
    '90 Mazda Capella. (2000 - 2003) My first Fatmobile. Converted to fun on veggie oil with a 2 tank setup. Died when supercharger stuck at max boost for weeks. Stretched head bolts.
    '80 Mercedes 300D. 2 tank conversion [Sold]
    '84 Mercedes 300D. 1 tank, no conversion. Replaced engine with rebuilt OM617A turbodiesel engine. Finally had good power. Donor for current Fatmobile coupe. (body parted out and carcass sold for scrap.)
    '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car)[sold]
    '98 Mercedes W202 C250 Turbodiesel (my car)[sold]
    Parts Car C220 1993 SOLD.
    '85 Mercedes Benz W123 300CD Turbodiesel single tank using 95% used cooking oil and 5% to 10% misfuel (where someone had filled diesel vehicle with petrol).


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  4. #4
    Join Date
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    Location
    Newcastle
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    Re: Blend Startup

    Yes I did what you have said and dropped the % down to 10%. I'll see how this goes tomorrow and get back to you both.

    Cheers

  5. #5
    Join Date
    Jan 2009
    Location
    Prescott, AZ, USA
    Posts
    273

    Re: Blend Startup

    Quote Originally Posted by PeterAC View Post
    I have a new 1980 300D that goes like a rocket on diesel. I have just started using a blend of approx 20% ulp and wvo. It runs great on the mix but is rough on startup on a cold morning. It is now just starting to stumble on some warm startups when sitting for 10 mins or more. On startup after a few revs it is purring.

    Will the rough start cause long term issues. Is the rough sometimes startup indicating what?
    I do not believe that the 1980 300D has a fuel line heater, unless an after market one was added. If there is no fuel line heater, then your problem is not too much ULP, but not enough.

    If your engine stops stumbling after warm startups from dropping your ULP percentage down to 10%, then you have solved your problem, but I doubt it will.
    Last edited by Jeffrey S. Brooks; 17th September 2011 at 01:08 AM.

  6. #6
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    Location
    Newcastle
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    Re: Blend Startup

    Problem solved, addressed two ways.

    1. Reduced the ulp to 10%
    2. Waited till the full glow plug cycle had finished by observing the dash lights.

    Thankyou all three for your input. Much appreciated.

    Peter<><

  7. #7
    Join Date
    Jan 2009
    Location
    Prescott, AZ, USA
    Posts
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    Re: Blend Startup

    You weren't waiting for the glow plug cycle to finish before cranking your engine?!!!

  8. #8
    Join Date
    Sep 2005
    Location
    WA
    Posts
    4,187

    Re: Blend Startup

    JSB,
    My comments are vehicle specific. Both PeterAC and I drive Mercedes 300Ds.
    For these cars, the GP light extinguishes long before the GP power is turned off by the GP relay.
    With diesel fuel, the GP light time is normally adequate glow to start the engine reliably.
    When using straight veggie or veggie blends, for the first cold start of the day, it is advisable to wait for a full glow period (ie the GP relay times out) before cranking to ensure reliable starting of the engine. After that, the engine retains enough heat that the GP Light time is sufficient glowing for reliable starting.
    Usually, if my 300D engine is warm - hot, it is not necessary to wait for the glow at all. I just crank and go.

    Too much petrol in the blend will cause problems with hot starting as the engine "heat soaks" the fuel system, causing the petrol to boil from the veggie and causes vapour lock. Once the engine starts, the airflow cools the fuel pipes and the blend is at a low enough temperature that the petrol does not boil.

    I believe that the most likely location of the vapour lock is in the injector lines themselves, as the slow pressure rise caused by the boiling petrol pushes the fuel into the injector return lines. It then takes much more cranking to push the petrol vapours out of the injector lines, before fuel hits the injectors. The fuel being pumped into the injector lines will still boil the petrol off, as the temperature is still too high.

    If this is your problem, try putting a damp cloth on the injector lines before cranking. You will still need to crank more, but the fuel pumped into the injector lines will be cooler and the petrol will not be boiling off, so the starting should be more reliable.
    When running, remove the cloth to avoid other issues.

    Better still, reduce the % petrol in the blend as PeterAC has.

    Regards,
    Tony
    Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

    Current Vehicles in stable:
    '06 Musso Sports Crew Cab. Running on used cooking oil with 5% to 10% misfuel.
    '2014 Toyota Prius (on ULP)


    Previous Vehicles:
    '90 Mazda Capella. (2000 - 2003) My first Fatmobile. Converted to fun on veggie oil with a 2 tank setup. Died when supercharger stuck at max boost for weeks. Stretched head bolts.
    '80 Mercedes 300D. 2 tank conversion [Sold]
    '84 Mercedes 300D. 1 tank, no conversion. Replaced engine with rebuilt OM617A turbodiesel engine. Finally had good power. Donor for current Fatmobile coupe. (body parted out and carcass sold for scrap.)
    '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car)[sold]
    '98 Mercedes W202 C250 Turbodiesel (my car)[sold]
    Parts Car C220 1993 SOLD.
    '85 Mercedes Benz W123 300CD Turbodiesel single tank using 95% used cooking oil and 5% to 10% misfuel (where someone had filled diesel vehicle with petrol).


    Searching the Biofuels Forum using Google
    Adding images and/or documents to your posts


  9. #9
    Join Date
    Nov 2007
    Location
    Victoria
    Posts
    445

    Re: Blend Startup

    Hi PeterAC,

    I found in my HJ45 Troopy at 60deg C fuel temp, with 20% ULP 80% WVO my fully rebuilt inline I.P suffered from vapor lock. Same temp 15% ULP runs beautiful.

    Experimentation is good! Glad you found what your engine likes.

    God bless, froggo.
    HJ45 Landcruiser Troopy
    Home made 2 tank system
    Blending in main diesel tank
    SVO/WVO Converted 18/01/08
    http://www.biofuelsforum.com/svo_users/3667-hj45_troopy_conversion.html

  10. #10
    Join Date
    Jan 2009
    Location
    Prescott, AZ, USA
    Posts
    273

    Re: Blend Startup

    Quote Originally Posted by Tony From West Oz View Post
    ...I believe that the most likely location of the vapour lock is in the injector lines themselves, as the slow pressure rise caused by the boiling petrol pushes the fuel into the injector return lines. It then takes much more cranking to push the petrol vapours out of the injector lines, before fuel hits the injectors. The fuel being pumped into the injector lines will still boil the petrol off, as the temperature is still too high...Regards,
    Tony
    Interesting hypothesis, Tony, but evaporation is a function of vapor pressure, thus vapor-lock is only likely to occur on the vacuum side of the lift pump, because the pressures in the injector pipes should be sufficient to keep petrol liquid at 100s of degrees C.

    I live in southern AZ where the summer time temperatures can rise over 120F (50c), however, very few petrol powered engines here experience vapor-lock, that means petrol can remain liquid at 120F (50c) with the reduced pressure of the lift pump.

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