[Vwdiesel] *help! bucking & smoking*

[James Hansen]

Sure thing Tad.  I wasn't thinking along those lines because having a turbo
runner off on the pressure side raises a certain amount of hell, and you
hear a lot of turbo if pre-intercooler and if post intercooler lots of
whooshing and fuss anyway, and fairly obvious noisy underhood fuss, unless
Rolf has too many subs with fat amps...   Some of these have default to
manifold pressure, some default to rpm dependent injection quantity. Don't
ask me which ones.
If a small pressure sensor line, it should just go into limp of one form or
another, reduced power, no enormous smoke quantity. They tend to react to a
situation when manifold pressure sensesd is lower than specified by reducing
fuel- which is an emissions issue, so it's not like that hasn't been thought
through. The maf in failing operation (increasing resistance) tells the ecu
that there is more air flowing than actual, which overfuels, hence the smoke

Besides, having a battery go flat won't make a runner coming off more
likely.  One electrical issue generally raises more, but yeah, eliminate all
the variables first man. Never just throw parts at it...
-james

> Guys - if it were me I'd still take a look at the turbo hoses first.
> 
> My reasoning is thus- if the boost charge was leaking out, the ECU
> would be
> delivering fuel based on the MAF reading (too much fuel, lots of
> smoke).
> *
> *
> *If you pull the MAF, it will default (if I'm not mistaken) to the MAP
> reading, which would actually be accurate (no pressure) so it wouldn't
> inject so much fuel.  *
> *
> *
> *In other words it would look like pulling the MAF fixed the issue, but
> really it would just mask the symptoms.  *
> 
> On Thu, Mar 25, 2010 at 2:32 PM, Bryan Belman <dieselwesty at yahoo.com>
> wrote:
> 
> > Great work James.
> > Rolf, I second that, I would order that from IDParts.com
> > I would not skimp on the MAF
> > Bryan Belman, Pt. Pleasant, NJ
> > 04 Jetta Wagon TDI PD, 100hp, 5sp -- running :)
> > 92 Jetta 1.6 Eco-Turbo Diesel -- running :}
> > 82 Diesel Westy 1.9NA -- running :)
> > 70 Type 1 stock Beetle -- Not running :(
> >
> >
> >
> >
> > ________________________________
> > From: James Hansen <jhsg at sasktel.net>
> > To: Rolf Pechukas <rbp at 4u2bu.org>; vwdiesel at vwfans.com
> > Sent: Thu, March 25, 2010 4:18:45 PM
> > Subject: Re: [Vwdiesel] *help! bucking & smoking*
> >
> > I would recommend our gracious site host.
> > That's IDparts.com, no?
> > You have to watch, the cheap ones have a high failure rate too.
> > -james
> >
> > > -----Original Message-----
> > > From: Rolf Pechukas [mailto:rbp at 4u2bu.org]
> > > Sent: Thursday, March 25, 2010 1:46 PM
> > > To: James Hansen; vwdiesel at vwfans.com; VW-TDI at yahoogroups.com
> > > Subject: Re: [Vwdiesel] *help! bucking & smoking*
> > >
> > > James
> > > u r a frickin' genius!
> > > unplugged the MAF and ran 1000x better
> > > problem solved
> > > gonna order up a replacement - any idea where to go?
> > > (thanks a million! seriously! I think this is about the 13th time
> uv
> > > bailed me out!)
> > > peace,
> > > Rolf in MA
> > >
> > >
> > > On Mar 25, 2010, at 3:15 PM, James Hansen wrote:
> > >
> > > > A dying MAF can run like absolute shit Rolf. A dead one usually
> just
> > > goes to
> > > > limp mode, but failure mode can vary.
> > > > I have seen a car with what finally turned out to be dying MAF
> run as
> > > you
> > > > describe, was in a friend's Dad's 03 Jetta.  Not that I'm so
> smart,
> > > but I
> > > > diagnosed it as a dead MAF when he stopped by on the way to the
> > > dealership.
> > > > He lives an hour away, and stopped in for coffee on his way to
> get it
> > > fixed.
> > > > The shop disagreed with my meager efforts, dissed VCDS as useless
> > > (yeah
> > > > right), milked him for a T belt, timing, rebuilt injectors, THEN
> > > replaced
> > > > the MAF and it ran properly. He was some pissed, and IIRC, got
> the
> > > injectors
> > > > gratis eventually.  Car would smoke like a chimney, and generally
> run
> > > like
> > > > it was way late in timing.
> > > > In VCDS, check your adaptation settings, and determine if the
> > > adaptation has
> > > > been lost as well.  If it is, there are some models that require
> a
> > > very
> > > > specific train of events to adapt.  Some do it just by driving,
> some
> > > need
> > > > you to jump through a couple hoops. If you have to jump through
> > > hoops, get
> > > > your court shoes on, 'cause it has to be done *exactly* as
> written
> > > and is a
> > > > real PITA. 05 Passat is an example of the PITA adaptation.
> > > >
> > > > Did the shop screw up the timing?
> > > > Man, anything is possible. It's a world away from the alt belt,
> but
> > > who
> > > > really knows unless you were standing there puffing hot breath on
> the
> > > tech's
> > > > neck while he worked on your baby. Most are competent, some
> couldn't
> > > install
> > > > muffler bearings if their life depended on it.
> > > > -james
> > > >
> > > >
> > > >
> >
> >
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