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2.5 tdi glow plugs?

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by markyzs180, Dec 18, 2009.

  1. JimLoskot
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    JimLoskot Member

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    [Jan 3, 2010]
    good point, I'll try that in the morning
    #41
  2. BahnStormer77
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    BahnStormer77 BahnStormer

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    [Jan 5, 2010]
    started first time at -2c.... I think I've finally got the hang of it....

    don't JSUT wait for the glow-plug light to go off... give it literally a minute or so longer and when the engine first soudns like it takes, just keep the key turned half a second longer....
    #42
  3. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Jan 5, 2010]
    I do that too, I generally wait until the airbag light goes out. If it's cold I do that twice and it will fire with two turns of the engine.
    #43
  4. adamss24
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    adamss24 Well-Known Member

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    [Jan 5, 2010]
    Thats not normal chaps ! -4 this morning and the glow plugs stay on for 4 sec then it fires straight away - first turn of the engine. I can get a video of me a6 starting (been off for 2 weeks as we dont drive it much) just dont know how to upload it on the forum. Even without leaving the glow plugs on it still starts fine with first turn of the engine. If the battery is in healthy condition and the compression is within spec then it would start without glow plugs...
    #44
  5. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Jan 5, 2010]
    Then why fit glow plugs ..... ?

    There's nothing wrong with the compression or battery in mine, its just the glowplugs that are tired.
    #45
  6. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Jan 30, 2010]
    I'm going to get on and order these and have a go myself.

    My symptoms are:

    • Cold starting is sluggish, but if I give the glowplugs three goes it will fire with about three turns.
    • Hot starting is fine.
    • If I start the car and drive it for about a minute - say round to the front of the house to wash it - when I go to restart it after a short while 45 mins or so - then even with three heats it will turn over for a good 5-10 secs before firing. As a result lots of unburnt fuel will come as smoke out of the exhausts.
    Anyone any thoughts on this?

    I'm going to do the glowplugs first, as long as I don't shear them off they are cheap enough - then if it's still no better I will have to investigate further and get it scanned.

    I've been told that when glowplugs are knackered the light will flash - I've never had that, has anyone else experienced it?
    #46
  7. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 5, 2010]
    Well I fitted mine today, and can say that it was pretty straightforward and gave me no problems. Four of them are easily accesible, on the rear O/S one I had to take the turbo pipe off (2 jubilee clips) and the front N/S was a fiddle but I managed it ok with a knuckle join on the socket set.

    I used a 1/2" drive socket set, which was fine, but it would have been easier with a 3.8 drive set, you will need a 10mm deep socket and the flexible knuckle as I mentioned. If you don't have one then I think you could still get to the front N/S plug by removing the pipe between the intercooler and intake manifold. That involves about 6 nuts and 2 allen keys from memory.

    I gave mine a squirt of WD40 when I started, and was just gentle with the ratchet when I undid them, but they all came out no problems. Fingers crossed for the morning ..... :thumbsup:

    It's a pretty straightforward DIY job in my opinion, and not worth the two hours a garage would probably charge you.
    #47
  8. markyzs180
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    markyzs180 Member

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    [Feb 6, 2010]
    :applaus:

    Well done James...you obviously have a deft touch, fancy a trip up to the midlands to do mine? or I could pop in next time I'm down in Christchurch visiting my sister?? Just let me know whats easier for you......... :laugh:

    Fingers crossed she'll fire up first time in the morning, keep us posted :icon_thumright:
    #48
  9. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 6, 2010]
    If you're down this way mate I would be more than happy to give you a hand ;)
    #49
  10. markyzs180
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    markyzs180 Member

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    [Feb 6, 2010]
    thats very kind of you bud but i was only joking ;)

    how did it start today? its pretty warm up here (+4c) though another cold snap is due to arrive next week!
    #50
  11. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 6, 2010]
    Hmmmmm - not really any better :(

    It was about 6 deg here when I started it, the glowplug light went out virtually immediately and the car fired after a couple of turns but still spluttered for a second before running sweetly.

    The biggest problem is this, if I start the car and run it for about one minute (ie to drive it around to the front of the house to wash it) - when I come to restart it after say 40 mins or so, it will wind for a good 10 secs or so before firing, when it catches it kicks out quite a lot of unburnt fuel from the exhausts - so in my mind it can only be one of a few things now:

    • Battery - this is a possible as it's never been replaced in the three years I've had the car, I will get it tested.
    • Fuel pump timing - was set about one year ago with the replacement engine - need vagcom to check.
    • Low compression - lets hope not ......
    • Intake manifold flap - research reveals they can fail - needs vagcom again.
    • Thinking aloud here - the glowplugs only work when the engine is cold, so there must be a sensor which measures engine (water) temperature? If this were faulty then the glowplugs might think the engine is warm when it isn't so aren't heating?
    Any ideas and experiences gratefully recieved.
    #51
  12. markyzs180
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    markyzs180 Member

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    [Feb 6, 2010]
    Sorry to hear that James, was hoping it would sort it for you....

    Once mine has started it's fine and will fire up first time all day? It takes longer to start if its been left for a couple of days which makes me think it might be leak off pipes or pump timing but saying that it started first time today (at +5c) even though it had been standing since Wednesday evening? I have vag-com'd it and there are no faults showing but I still haven't had the pump timing checked, next on the list of things to do. Not looking forward to the return of the cold weather next week.....
    #52
  13. Leea4tdi
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    Leea4tdi Member

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    [Feb 7, 2010]
    hmmm sounds to me like you are getting a very small ammount of air entering the fuel system, thats why over time it is taking a while for the fuel to pick back up.
    #53
  14. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 16, 2010]
    Pretty spot on that man!

    There was a small split in two of the return pipes from the injectors: this allowed the fuel to run back and meant that after it had been stopped for a while it needed to crank new fuel up to the injectors.

    I'll have to wait till tomorrow to know for sure, so fingers crossed!
    #54
  15. markyzs180
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    markyzs180 Member

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    [Feb 16, 2010]

    glad you've got to the bottom of it james...any chance of the part number for the leak off pipes :)
    #55
  16. BlackQuat
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    BlackQuat Well-Known Member VCDS Map User

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    [Feb 17, 2010]
    Glad you got it sorted! Big job to sort out? Also does that mean you'll be better on fuel now?
    #56
  17. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 17, 2010]
    Hmmmph maybe spoke too soon :(

    It coughed a bit this morning from cold, but still took about ten seconds to fire after work this evening..... Will give it a few days and have a rethink, Vagcom didn't show up any errors codes though.

    Maybe, but it's only the low pressure return so I doubt the leak was significant. I think it was more air coming in than fuel coming out which is the issue.
    #57
  18. markyzs180
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    markyzs180 Member

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    [Feb 17, 2010]
    Oh man.... :(

    Pump timing next then James....lets hope its that, don't want to mention the comp------n word in full.....:(
    #58
  19. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 17, 2010]
    I forgot to ask if they checked the pump timing yesterday. I'm really hoping it's not compression..... although on the plus side, the engine is still under guarantee from the place I bought it from I think, reluctant as I am to ever go near there again......

    Its going really well, so I'm hoping there's not 'that' much wrong!
    #59
  20. dawr
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    dawr New Member

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    [Feb 19, 2010]
    Hi

    I'm a newbie here and joined this site to see if anyone had the same problem as me and looks like there are. I have EXACTLY the same issue with my 2004 2.5tdi Allroad. I bought it as a "Approved Audi" from a main dealer at the end of December and its been back to the garage at least 6 times since with the starting fault. They have changed everything and the problem (car still at garage tonight) has been referred to Audi Technical in Germany as they are at a loss why the car is sluggish and fails to start first time from cold. Starts fine second time or if you over crank for about 1/2 second but they admit there is something not right but all the diagnostics point to NO FAULT. Its beginning to really bug me and I'm worried they are going to say there is no more they can do. There MUST be something at fault here, I have a 20 year old Mazda which starts first click every morning warm or cold!!!!

    Let me know if you get anywhere with yours.

    Cheers
    #60
  21. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 19, 2010]
    Your issues are a bit different to mine. Mine seems to start ok(ish) in the mornings - it's later in the day that it's not so good. I parked it at work this morning, and just over ten hours later went to start it and it wound for ages before firing, and chucked out loads of smoke.

    Why is starting later in the day different to the mornings? I don't know.

    Will be back to the garage next week.
    #61
  22. adamss24
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    adamss24 Well-Known Member

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    [Feb 19, 2010]
    Timing is out or coolant temp. sensor is duff. Either will retard the timing to such extent that it wont fire on first crank. I would rule out the loss of compression as its starts ok on a cold engine. Would not hurt to take the rocker cover off on both sides of the cylinder banks and see how the cams are...
    #62
  23. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 19, 2010]
    Thankyou. Timing is a definate possibility, why coolant temp sensor? What does that determine?
    #63
  24. Leea4tdi
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    Leea4tdi Member

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    [Feb 20, 2010]
    Glad to be of service! but cant really see what else would cause this to happen if the glow plugs are getting good 12v power and are hot then she should fire up straight away as that smoke you see is from the unburnt fuel in the cylinders so i guess theres plenty of fuel there!! have you put a meter to the glow plugs when the light is on to see what voltage there getting??
    Last edited: Feb 20, 2010
    #64
  25. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 20, 2010]
    Still not fixed though .... :(
    #65
  26. markyzs180
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    markyzs180 Member

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    [Feb 20, 2010]
    I'm going to try and look at the pump timing on mine tomorrow...will let you know how I get on...
    #66
  27. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 21, 2010]
    Any luck Mark?
    Last edited: Feb 21, 2010
    #67
  28. markyzs180
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    markyzs180 Member

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    [Feb 21, 2010]
    soz james, 4 inches of snow put paid to it...got snowmen to build lol
    #68
  29. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 21, 2010]
    Is that because the car wouldn't start? lol...
    #69
  30. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 24, 2010]
    Car has been back in again today and they're keeping it overnight to check the cold start in the morning. Over the last few days my ECON light has come on in the aircon too :(

    Vagcom checked again and nothing at all, so hopefully the system just needs a recharge. I had it done less that two years ago but I've had a few engines since then ..... I'm hoping that no fault codes will rule out glowplug errors, intake manifold flaps etc etc. Fuel pump timing was within parameters too.

    The only thing they could find slightly suspect was the battery. Leaving the lights on for half an hour and trying to start it really pulled the battery down, more than it should have done apparently. So here goes with a new battery.....
    #70
  31. BlackQuat
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    BlackQuat Well-Known Member VCDS Map User

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    [Feb 24, 2010]
    Hope you sort it lads. Mine takes abit to start but I'm just living with it at the mo. I'll sort it over the year I'm sure lol.

    Econ will probably just be low gas. Who charged it last time? If it was Kwik fit, apparnetly they put in a small amount.
    #71
  32. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 25, 2010]
    No it wasn't KwikFit - I'd never use them through choice.....

    Last time it was low the light didn't come on, thats all that's making me nervous!
    #72
  33. adamss24
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    adamss24 Well-Known Member

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    [Feb 25, 2010]
    The ECU determines the time the glow plugs remain energised by measuring the coolant temp. If thats duff (it does have 4 pins: 2 for the gauge and 2 for the ECU) and the engine thinks is too hot, then the glow plugs wont stay on for long hence the hard to start engine. If the CTS is duff, the advance solenoid does not get engaged and the ECU wont inject more to warm up the cylinders(like choke on older engines). If the signals from the CTS are outside the limits, then the ECU will disregard it alltoghether and take its readings from the fuel temp. sensor. These engines have a closed loop information system and the ECU monitors them all. When one fails it might work trough other sensors-allbeit at reduced power(aka- Limp Mode)- or it will shut the engine down. As i said in previous posts: check the timing, take rocker covers off and check the cams and lifters for wear(they known to wear wich means at times some engines will use 1-2 out of 4 valves per cylinder ! Also hard starts from cold could be due to the injector pump and it will flag a code when the pump cannot provide more advance and fuel pressures. Do a google search for VP44 pumps/dead codes. Worn injector nozzles also could lead to hard to start engines from cold but they should work fine to 200k. Also check that you have an air tight fuel system and replace the fuel filter with a genuine/Henghst item and make shure you replace the 1 way plastic valve from the filter. Also pay atention to the leak off injector pipes as they will allow air in if they perished.
    #73
  34. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 25, 2010]
    Thankyou for a very comprehensive reply.

    The engine was replaced with a recon one this time last year, so fingers crossed cam wear won't be the problem. VP44 errors are a definite possibility I've been keeping my fingers crossed it isn't!

    With the new battery the car started well this morning apparently, so when I get it back I will see how I get on with it over the next few days.

    I only ever use genuine filters, but swapping the fuel filter may be worth a go. Pump timing is fine, that's been checked. Fuel pressure is ok, except when the battery pulls itself down, hence trying a new battery to prove/disprove that.

    No other errors came up, but if still no joy I will try a new CTS anyway, although the glowplug system has all been checked for voltage etc and seems to be ok.

    The only other thing to be suggested is the flap in the inlet manifold, apparently a scan may not pick this up either. I'll liase with the garage when I get the car, and report back later.

    By "leak off injector pipes" do you mean the return pipes off each injector? If so, as I said below they were checked last week and two replaced then.
    Last edited: Feb 25, 2010
    #74
  35. markyzs180
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    markyzs180 Member

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    [Feb 26, 2010]
    Sorry James, I'm beginning to wish I hadn't started this thread :ermm: I ahven't changed a thing on mine yet and I think you're running out of things to change! :(

    Was it any better with the new battery? Trouble is you're not going to know for definate until it gets colder again (been pretty warm here last few days)
    #75
  36. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Feb 26, 2010]
    Yeh I've only had it back a day, so not really done enough starts to judge. It certainly winds over much quicker with the new battery!
    #76
  37. markyzs180
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    markyzs180 Member

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    [Feb 27, 2010]
    fingers crossed then mate :) if it is ok i think you've pretty well eradicated every possible starting issue you may have in the future!
    #77
  38. JimLoskot
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    JimLoskot Member

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    [Mar 3, 2010]
    little update on my situation;
    I'm still having problems cold starting even when its above 5 degrees, lot of smoke out the back when it does turn over (unburnt fuel).
    Noticed the other day that the temperature guage doesn't really move, even on a long motorway journey. I presume this means that the engine temp sensor (or is it coolant temp sensor?) is knackered.
    Is this difficult to replace? would this be causing the cold start problems as well?
    Any advice gratefully recieved.
    Thanks
    Jim
    #78
  39. adamss24
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    adamss24 Well-Known Member

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    [Mar 3, 2010]
    Start by replacing the coolant temp. sensor, its about £35 at the dealer. If that does not sort it, then you are looking for a new thermostat wich is a cambelt off job !
    #79
  40. JimLoskot
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    JimLoskot Member

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    [Mar 3, 2010]
    Thanks.
    Is it an easy job? and where is the sensor located?
    #80

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