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Bkd cold start: better on decline?

Discussion in 'A3/S3/Sportback (8P Chassis)' started by Ade6, May 25, 2013.

  1. Ade6
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    Ade6 Member

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    [May 25, 2013]
    My car when starting from cold. It takes abit more winding over and when it starts it puffs out abit of diesel smoke. Now ive parked my car on a bit of a decline the last 2 days and its alot better at starting. Glow plugs and loom replaced a month or two ago (could be a faulty plug) i cant remember what it was like before i replaced them! No fault codes in vcds. Any ideas? Thanks
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  3. TDI140
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    TDI140 Well-Known Member

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    [May 25, 2013]
    Do You always wait for glow plug light to turn off ? Even when weather condition are hot your engine will be cold so make sure glow plug light turns off before starting, also alow engine to cool down for aboit 40 seconds before turning off after driving​
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  4. fangio
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    fangio Well-Known Member

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    [May 25, 2013]
    Peugeots used to be bad for this, and it was usually caused by a very slight air leak on the suction side of the fuel pump, allowing the fuel to flow back to the tank.

    Hence a lot of winding over. Don't know if it would apply to Audi, though!
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  5. Mikemc
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    Mikemc Active Member

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    [May 25, 2013]
    +1 I've read many posts on here regarding that issue although i can't remember how it's sorted, maybe pressure tested?
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  6. SAiLO
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    SAiLO Enthusiast VCDS Map User

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    [May 25, 2013]
    If it's having a difficult cold start it could be due to weak battery, worn starter motor even cracked cylinder head.
    I'd start with checking the battery.
    If you get a puff of white smoke on startup could be an indication of cracked cylinder head allowing coolant to seep into the engine.
    Hope you get it sorted mate
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  7. Boon
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    Boon Active Member VCDS Map User

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    [May 25, 2013]
    White, Blue or Black smoke on start up?

    The glow plugs will only work when the coolant temperature is less than 9deg, even though the coil light comes on as normal...

    I would be checking, as said above, battery & starter - fuel system inc pipes, filter, pump (also any fuel in engine oil) & get some injector cleaner/purge & see what happens from that

    Mine has just over 120,000 on the clock and starts instantly both cold and hot so shouldn't be due to wear!!
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  8. Johnny Bravo
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    Johnny Bravo 6+1 Gears

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    [May 25, 2013]
    Tandem pump is loosing pressure. The fuel gets back in the tank and this is why the hard start. It stars better when parked with the front lower than the rear due to gravity doing its business keeping the fuel in the engine.
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  9. Ade6
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    Ade6 Member

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    [May 25, 2013]
    I read about the cylinder head but its not loosing coolant and its a strong smell of diesel, bluey white smoke!
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  10. fangio
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    fangio Well-Known Member

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    [May 25, 2013]
    Do you leave it ticking over for long periods?
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  11. Mikemc
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    Mikemc Active Member

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    [May 25, 2013]
    Blue smoke is usually oil
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  12. fangio
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    fangio Well-Known Member

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    [May 25, 2013]
    Bluey-white smoke is excess fuel being burnt out of the cylinders.

    Ever watched a bus pull away after ticking over at a stop for 5 minutes? You get the same effect, if you switch off after ticking over, the next time you start up. Not as much nowadays with all the electronic gubbins......
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  13. Ade6
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    Ade6 Member

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    [May 25, 2013]
    Im guessing one of the injectors are weaping after abit into one of the bores and its that burning off. Or maybe a faulty glowplug?
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  14. Mikemc
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    Mikemc Active Member

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    [May 25, 2013]
    Un burnt diesel is black. My turbo was leaking oil, my smoke was a bluey white
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  15. Ade6
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    Ade6 Member

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    [May 25, 2013]
    Just a quick update.. Took the fuel filter out today and sat in the bottom was what looked like black filings, i did a diesel purge the other week and added a can of redex.(may be **** collected?) What would it be like if the tandem pump was faulty?
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  16. the obese penguin
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    the obese penguin Member

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    [May 30, 2013]
    Jet black fuel filter and cold start issue ( not being started 6-8 hours ).. I would suggest tandem fuel pump is at fault.. £203 from ebay
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  17. Ade6
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    Ade6 Member

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    [May 30, 2013]
    Is there any way of testing the tandem pump? Ive tried it on a bit of a slope and it makes no diffrence. Replaced the fuel filter and cleaned the injectors with diesel perge and cleaned the fuel filter houseing and drove it for a couple of days and the fuel filter is still clean.
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