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New to MTD, Misfire problem BEW

Discussion in 'VW Mk4 Jetta, Golf, New Beetle, Passat TDI forum' started by mr2dux, Apr 22, 2012.

  1. mr2dux

    mr2dux New Member

    Joined:
    Apr 22, 2012
    Messages:
    4
    Car:
    2004 Jetta BEW
    Hi all
    I have a 2004 Jetta BEW, and a couple weeks ago it started running much like it was misfiring on a single cylinder. This started immediately after refueling, almost a whole tankful, from a station I was not familiar with. (bad fuel?). Since then, I ran through that tankful, and refueled at a station I know to have high diesel turnover, that I use often. No improvement in the misfire. So far, I have changed Air and Fuel filters, checked intake manifold (not as bad as I expected), cleaned the EGR diverter valve, and said a few incantations over the engine. Still no improvement.
    I had the valve cover off to check connections to solenoids, and they all seemed secure, but I did not remove and reseat them...(actually I didn't know how to get 'em off the injectors, and didn't wanna break something). Because it behaves as a single cylinder misfire, I suspect something related to a single injector.
    I have not run Vagcom on it (no cable), so I don't know what codes it may be throwing. What next?
    Thanks
    Mark

    ps: I'm highly incentivized to get this sucker fixed, because until I do, I'm in my backup car, a 1990 Volvo 240, with a passenger window that won't go up, no radio, and no power steering! (driven for two years by a teenager as his training car) Ick....what is this goo on the seat.....etc.
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  2. chittychittybangbang

    chittychittybangbang Administrator

    Joined:
    May 23, 2007
    Messages:
    20,946
    Car:
    2006 Jetta TDI
    Location:
    CT
  3. mr2dux

    mr2dux New Member

    Joined:
    Apr 22, 2012
    Messages:
    4
    Car:
    2004 Jetta BEW
    Next step

    Thanks much!
    I like the idea of the clear container, and connecting the two lines to the fuel tank. I wasn't sure what to do about lift pump putting fuel all over the place. Will do that this coming week, and post the result. Also I have an auto zone close, so will pull codes from there to check on the misfire. Will get back to forum in a few days. This help is awesome!
    Mark
    Last edited by a moderator: Apr 22, 2012
  4. mr2dux

    mr2dux New Member

    Joined:
    Apr 22, 2012
    Messages:
    4
    Car:
    2004 Jetta BEW
    The update on "misfire"

    First thing is that I ran a can of DieselPurge through the engine (Thanks much for instruction video!), which seemed to improve things slightly. Just slightly. I then pulled codes and got a MAF code, P0101, and an engine speed sensor code. Cleared them with vagcom, drove for a bit, and then code P0101 returned. No engine misfire codes however.

    Before I just drop a new MAF sensor in, I have heard that some of the things that can give confusing readings are any leak in the intake (i think I know someone with a smoke generator to check for leaks), and/or a stuck EGR bypass valve. PCV valve too? Will try to check these.

    Also, because this issue began immediately after a refuel at a station that probably doesn't do much diesel business, I suspect my lift pump with 240K on it just might be a bit gummed up. I think I will change that as a service item, just in case. Got one this morning, so will try it tonight. Will keep you guys posted. Any video on this install?

    Thanks! Mark
  5. chittychittybangbang

    chittychittybangbang Administrator

    Joined:
    May 23, 2007
    Messages:
    20,946
    Car:
    2006 Jetta TDI
    Location:
    CT
    no but here's some tips
    use large wrench or prybar as punch to turn cap holding down pump, it's really tight
    pinch fuel lines at base with pick to release the lock at pump line don't force them. look closely and you'll see the button
    lay plastic sheeting or lots of paper towels, will prob spill some fuel and don't want it soaking into carpeting.

    lift pump could just be gummed up otherwise but check other causes of low power (see FAQ) before replacing it.
  6. mr2dux

    mr2dux New Member

    Joined:
    Apr 22, 2012
    Messages:
    4
    Car:
    2004 Jetta BEW
    more update

    Well so much for that. I'm happy to have a new lift pump in the tank, but no diff in performance. Will check/replace vac lines, smoke test intake, and recheck EGR diverter valve. Also had a code for engine speed sensor. Where is this? Thanks
    Mark
  7. shuswap

    shuswap Member

    Joined:
    Dec 12, 2010
    Messages:
    181
    Car:
    2005 Golf TDI auto
    The engine speed sensor appears to be located to the right of and (roughly) level with the bottom of the oil filter housing/block. This according to the diagram I have on hand. It appears to be pretty small with a bolt or two attaching it to the block.

    My new lift pump has made no difference to performance or fuel economy. Not that I could understand how it would have helped either, but had read reports it improved both.

    You certainly do not want to know what that goo on the seat is.
  8. artemis

    artemis New Member

    Joined:
    May 3, 2012
    Messages:
    6
    Car:
    VW Passat 2.0 TDI 2005.5
    The misfire is also caused by a consumed camshaft lobe.

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