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audi a4 tdi 170 lumpy idle

Discussion in 'Audi S4/A4/A4 Cab (B7 Chassis)' started by mike81, Jan 15, 2013.

  1. mike81
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    mike81 New Member

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    [Jan 15, 2013]
    hi guys looking for a bit of advice,a month ago i got myself an audi a4 tdi sline 170 it has done 100,000 miles the first week of owning the car was fine, now cold start can be a little longer to start but also it hunts alot and puts alot of very smelly smoke out the back,now its had a full service and that made no difference.if i unplug the maf sensor it runs sweet no smoke and no idle issues,so i put a brand new bosh 1 on but still the same,i was told that the fuel filter looked like there was oil mixed in with it not much but still oil,if any 1 has had same probs with there a4 or if any 1 could help would be much help cheers mike
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  3. NHN
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    NHN Retrofitter - Audi - VW - Skoda - Seat Site Sponsor VCDS Map User

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    [Jan 15, 2013]
    Swap the fuel filter out mate & see if this improves it, its small change & you could do yourself more than likely.
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  4. mike81
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    mike81 New Member

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    [Jan 16, 2013]
    hi,fuel filter was changed an monday
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  5. sidibear
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    sidibear Looking for Zombies !! Staff Member Moderator

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    [Jan 16, 2013]
    An air leak on the inlet hose can cause lumpy idle.
    #4
  6. Purdy99
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    Purdy99 Member

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    [Jan 16, 2013]
    hi mike, this is what i've recently done to my car and it has improved the idle loads, it looks loads harder then it is to do, first i used a restricting gasket on the EGR/Intake Valve or throttle valve, (not sure the Technical name) but its located on the end of the inlet manifold, (will get you part numbers when i get home, all OEM parts from audi) you'll see in the pic, (click to enlarge)
    lunapic_131671390780050_13[1].jpg
    when you remove this you'll notice a build up of loads of ****, mainly because of the EGR system, my car has only done 57000 miles and this is what it looked like, hard to see tho as i took the pics on my phone,
    IMAG0147.jpg
    IMAG0149.jpg
    as you can see its full of ****! next thing to do is clean all this out, using brake cleaner, or anything that will budge the stuff, but as you'll notice in the next pics, if yours is like mine the casting was shocking, and left quite a big lip on the inside, looks as if it wouldnt do much but it can affect air flow by alot,
    IMAG0151.jpg
    using fine emery cloth, and a dremel i started filing that lip back, until i was happy it was smooth,
    IMAG0153.jpg
    IMAG0156.jpg
    IMAG0157.jpg
    as you can see its quite a big difference, putting it all back together i replaced all gaskets i had removed, but the EGR gasket i replced with a Updated gasket, as i said earlier when i get home i'll get you the part numbers, all can be bought from audi/vw/seat and so on,
    but with the gasket itself you'll noticed i've drilled 4 3mm holes around the center hole, this is because if you restrict the EGR valve to much it'll bring up a Warning on the dash, and also (heard this as a rumour) blocking it off completely it will still run fine, but apparently can cause the turbo to overheat if you have a heavy foot, i'll also put the pic of the tools i used to get the EGR/throttle Valve off,
    IMAG0096.jpg
    "above" the updated EGR valve gasket with 4 3mm drilled holes,
    IMAG0158.jpg
    "above" tools used to remove the EGR/throttle valve thing..ie
    was a really easy job, looks scary but honestly its not to bad, one problem you might get is the two bolts to remove the pipe that conects to the EGR valve from the exhaust manifold (soild steel pipe, round the top of the engine, near the bulk head) are a very weird shape, unlike allen key or torx, it has more splines then them, luckly without even knowing i had the correct tool bits to fit, but i'm sure you could use an allen key without causing to much damage,

    doing all this as i said improved it loads for me, and i hope this helps, if you need a more detailed description message me, this is just a quick one as i'm at work haha,
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  7. mike81
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    mike81 New Member

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    [Jan 16, 2013]
    hi purdy99,thats a great help,i took it to my local garage this afternoon they took the egr valve off and they said it was the worse they had eva seen lol,anyway they cleaned it and re fitted it but no difference so looks like its going to be the tangem pump but thanks for all the hep cheers guys,will update when get 1 fitted
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  8. AudiB7Jay
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    AudiB7Jay Member

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    [Jan 17, 2013]
    I have this problem for the 1st start up of the day extremely lumpy start :/ is it just the cold?
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  9. Purdy99
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    Purdy99 Member

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    [Jan 17, 2013]
    as i've said above, all parts cost me around 10quid and it sorted out cold idle spot on for me,
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  10. mike81
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    mike81 New Member

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    [Jan 17, 2013]
    i find mine worse when warm :(
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  11. mm707
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    mm707 Member

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    [Jan 18, 2013]
    when I cleaned the egr I also removed the inlet manifold ( easy enough job ) and found that the flaps inside were really covered in crud, cleaned with carb/choke cleaner and fitted a new vacuum actuator ( this controls the flaps ) for about £10, when I dismantled the old one it had a split in the diaphragm which I believe is fairly common. Cured my rough idling and slight hesitation issues between 1600 - 1800 rpm
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  12. craiga
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    craiga Member

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    [Jan 19, 2013]
    Well my 170 had the lumpy idle and then got very smelly fumes out the back. Got motor checked and the tandem pump seal had gone. This in turn lead me to need a fuel pump too. This was all found out when I went to get remap dpf and egr removal. Also front lower intercooler and turbo oil seal gone. All fixed now and the car is a rocket. Drives like new and pulls like a train. Pain on the ass still. So much to fix after crimbo
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  13. mike81
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    mike81 New Member

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    [Jan 21, 2013]
    hi guys,thanks for all the replys,have passed info to my local garage where car still is and they are looking into it they have taken both intercoolers off both had oil residue in which have now been cleaned hope fully i will get this sorted soon thanks again all
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  14. DERV-ers
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    DERV-ers New Member

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    [Feb 7, 2013]
    hows the work coming on??? did you ever get it sorted???
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  15. adamss24
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    adamss24 Well-Known Member

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    [Feb 7, 2013]
    I bet that the garage never worked on tdi's before, every diesel will have oil coating in the intercoolers, it means you're not driving it on boost often hence the turbo seals pass oil into the intake ! I bet you'll get a nice fat bill at the end and still no better ! As above, tandem pump can let oil mixing into the diesel but that's easy to see if they take a fuel sample out of the tank...
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  16. fasttdi
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    fasttdi New Member

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    [Feb 15, 2013]
    Purdy99 did you manage to get round to them part numbers???
    mines a 170, really lumpy idle until its fully warm. Really want to do what you've done cos it's doing my nuts in!
    #15
  17. mike81
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    mike81 New Member

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    [Mar 27, 2013]
    hay guys,aint been on here for a little bit but update on my car its all sorted,had inlets taken off and cleaned also egr valve still didnt sort it but it turned out my timing on the exhaust cam was out by nearly a tooth had it reset and car is bang on,pulls 100 times betta dose'nt smoke no smell and idle is perfect :o.k: i am 1 happy audi owner cheers for all help and advice ive had
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  18. ricochet
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    ricochet Member

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    [Apr 17, 2013]
    Is exhaust cam timing something totally different to valve timing? Also heard that diesel pump timing needs to be correct? Having similar problems with my 170 TDi A4 quattro.
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  19. mike81
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    mike81 New Member

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    [Apr 17, 2013]
    From what I gather no because the exhaust cam also runs the rocker that run the injectors so if exhaust cam is out slightly then the injectors are coming in at the wrong time
    #18
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  20. ricochet
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    ricochet Member

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    [Apr 18, 2013]
    Cheers mike81, did sound like a daft question even from a suck, squeeze, bang, blow fifth year physics (eg, inlet must linked to exhaust)kinda theory, but the way these things are built nowadays, I felt I just had to ask, Thanks again.

    Does anyone know if the diesel pump is ran from the timing belt, or is it electric, or other??
    #19

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