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2.5 v6 running on biodiesel

Discussion in 'A4/S4 forum(B5 Chassis)' started by pdf11, Sep 26, 2011.

  1. pdf11
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    pdf11 New Member

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    hi all. I've been running my '99 a4 avant 2.5 v6 on 50/50 biodiesel mix since april, covered around 6000 miles with no troubles at all. The only problem it can have is starting in a morning, it sometimes takes for ever to fire up. Once its started though, its fine for the rest of the day. just wondering if anyone else is running a v6 this way and offer any solutions to 1st ime starting!!....
    cheers
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  2. S4_dan
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    S4_dan Fire up the Quattro!

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    What are your glow plugs like? Maybe the combustion gasses from the bio fuel is killing or putting a film on the plugs effectively reducing the heat from being transferred?
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  3. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Is it PROPER biodiesel?

    If so, theres generally no problem running it on a Bosch VE pump as used on the 2.5.

    If your using SVO or filtered WVO thats a completely different story.

    Have you changed your fuel filter at all? Bio can often dissolve various **** from the tank and lines which can clog up the filter.
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  4. pdf11
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    pdf11 New Member

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    thanks for the replies. glow plugs could be an idea, its done 151,000 so may need changing. its good bio, been making it for 5 years and not had this problem before, changed the filter after about 2 tanks when i bought it. completely bypassed the glow plugs!!! lol.
    could someone tell me how to check the plugs, is it a case of taking each one out or will it come up as an error code?
    thanks for your help....
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  5. S4_dan
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    S4_dan Fire up the Quattro!

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    take the plug out and inspect it, some break down over time. To test, have a spare 12v car battery ready and a jump lead. connect plug to the battery and wait a few secs, should glow red pretty quickly! If it takes time, then change them.

    A bit like spark plugs, always better to replace all rather than just one!

    If you haven't changed them and had the car for a while, then for the price, I'd just change them anyway.
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  6. adamss24
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    adamss24 Well-Known Member

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    be very carefull when removing the glow plugs, theey have a tendency to snap in the head ! Soak them in plus gas/wd40 penetrating oil for a day or 2 and make shure the engine is hot...
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