89 200 Turbo SAGA goes on ...Boost leak tests.

LL - NY larrycleung at gmail.com
Tue Jun 7 22:42:32 EDT 2005 

Unfortunately, you can't use a simple shaped fitting like that on the later
10V cars. It's sort of a lopsidded oval. 

LL - NY

On 6/7/05, Kneale Brownson <kneale at coslink.net> wrote:
> You can use something like this:
> 
> http://photobucket.com/albums/v48/chrisanjenn/Audi%20S4/?action=view&current
> =Press_Test_2.jpg
> 
> to test the intake hoses for leaks.  You insert this in the large hose
> coming from the air filter box and apply 10 pounds or so of air pressure.
> You'll hear the leaks, so then you just have to trace them down.
> 
> At 08:54 PM 6/7/2005 -0400, LL - NY wrote:
> >You have a BOOST LEAK!
> >
> >Check the Michelin Man hose as well as the lower Intercooler hose
> >as I described. This narrows things down a lot, it is a mechanical,
> >not electrical issue. Check ALL hoses, and also look into the igloo
> >like air metering head boot. To properly inspect, most of these items
> >will have to be removed, and flexed. My car's boot
> >failed a couple of years ago, and the leak was NOT obvious (one of the
> >little right angle fittings of about 1/2" diameter cracked).
> >
> >Also, have you checked the crankcase breather hose that runs up the
> >crankcase vertically from the driver's side of the engine block (It's
> >2 diameters, about 1inch at
> >the crankcase, tapers down to about 1/2" at the top, and has a metal
> >crossover pipe than runs to (I think, now running strictly from
> >memory) a 3 way hose to the intake manifold. These often get soft and
> >collapse under vacuum when they fail, or
> >they clog with sludge. Can be cleaned out using carb/fuel injection cleaner.
> >
> >You really need to go through Scott Mockry's excellent website, go to
> >the "Secrets of High Boost" and follow the links for the maintenance
> >issues one should do BEFORE you modify the car (I know, that's not
> >your goal, but the maintenance he outlines and gives instructions to
> >are what you need to do).
> >
> >http://www.sjmautotechnik.com
> >
> >HTH, and Good Luck!
> >
> >LL - NY
> >
> >On 6/7/05, Cat     ^. .^   ~ <iceisit at earthlink.net> wrote:
> >> LL - NY wrote:
> >> >Fay,
> >> >
> >> >One thing to consider while looking for a boost leak would be
> >> >to use the "boost gauge" function of your trip computer (see
> >> >your owners manual as to how it functions if you don't already
> >> >play with it. Just pay attention to the driving while you play with
> >> >it if you're on the road, it can be quite distracting!). If the car is
> >> >functioning totally correctly, if you are hard on the gas, especially
> >> >at higher speeds (such as accelerating up an steep highway hill,
> >> >don't know if you have those in Flagstaff), you should see 1.4
> >>
> >> only goes to .7 for the most part
> >>
> >> maybe 1.0 for a nano second
> >>
> >> >on
> >> >the gauge and hold as long as you hold the pedal down.
> >> >If the computer is holding back some boost, (don't
> >> >recall the all of the conditions for that, although one of these
> >> >conditions is a non-functioning WGV, see previous posts on that)
> >> >it'll go to 1.2 and hold.
> >> >
> >> >BUT, if you have a fairly substantial intake system leak (like
> >> >a bad MM (ribbed) hose or lower intercooler hose) you may
> >> >end up with 1.1 or less, if the leak is QUITE severe, it will have
> >> >a hard time staying at 1.0 (which means the engine boosts until
> >> >it reaches outside air pressure (1.0 atmospheres), then the rest
> >> >of the boost leaks away, but the engine is expecting more).
> >>
> >> yuppers, that sounds like it !
> >>
> >> >Now, two places to check for leaks not mentioned:
> >> >
> >> >1.  Lower Intercooler hose. The large about 3" diameter J-shaped hose
> >> >    that runs from the bottom right of the intercooler (radiator
> >> >looking thing with
> >> >    ribbed MM (for Michelin Man) hose that runs to the top right of
> >> >it, directly
> >> >    from the engine) to the turbo-charger. They are VERY thick rubber, so
> >they
> >> >    can sometimes fail, but look intact, and their thickness lets them
> >> >fake integrity
> >> >    for a long, long time, (like 16 years). When I finally replaced
> >> >mine, it was
> >> >    cracked through 3/4 the way around, and yet the car still ran (not
> >> >super well,
> >> >    but it ran). Fixed the car. It's NOT cheap (around $120 about 2
> >> >years ago), and
> >> >    is likely a dealer only part, but you need to remove yours in
> >> >order to find out
> >> >    which of the two types your car has. One is three pieces with a hard
> >plastic
> >> >    pipe in it, the other is a single piece rubber hose. BTW, this
> >> >hose is a pain to
> >> >   get to, easiest to get to if the front bumper (easy to remove) and
> >> >grille, are
> >> >   removed from the car.
> >> >
> >> >2. The intercooler itself. The intercooler has an aluminum center
> >> >section (core) and
> >> >    plastic end tanks, which are crimped to the core. With time, the
> >> >crimps can fail
> >> >   and there is leakage at the end tanks. But, you ask, how can I tell
> >> >that air is
> >> >   leaking into ... air?
> >> >   Easy, because there is a notable amount of oil mixed in intake
> >> >tract air (don't
> >> >   really know why, anyone? Bueller?), wherever there are air leaks,
> >there are
> >> >   oil leaks. Feel the intercooler on the bottom, especially near the
> >> >end tanks.
> >> >   If there is oil present, there is likely a leak.
> >> >
> >> >HTH,
> >> >
> >> >LL - NY
> >> >
> >> >
> >> >On 6/7/05, David Conner <conner at cfm.ohio-state.edu> wrote:
> >> > > Fay asks...
> >> > > "Are you saying it is the Turbo which is not working."
> >> > >
> >> > > Hi Fay,
> >> > > No, that's not what I'm saying.  What I'm saying is you have a 16 year
> >old
> >> > > Audi with a turbo attached to the engine.  Turbos create a >lot< of
> extra
> >> > > of heat and stress under the hood.  Your car likely has multiple
> >problems.
> >> > > Maybe a single one is causing it not to start, but there could very
> >well be
> >> > > a number of poor electrical connections, etc that are degrading
> >performance.
> >> > >
> >> > > Compared to a non-turbo engine there are more electrical sensors, wiring
> >> > > and hoses under the hood.  The turbo generates an extreme amount of heat
> >> > > which takes a toll on hoses, wiring, plastic, and everything else
> >under the
> >> > > hood.  The turbo creates a lot of >pressure< in the air intake system
> >which
> >> > > will cause failure of age/heat weakened components (hoses).  The heat
> >> > > stress can also lead to a cracked exhaust manifold.  Leaks or cracks
> both
> >> > > result in vacuum leaks which cause poor running or no-start condition.
> > The
> >> > > turbo pressure >will< blow off a hose if a clamp was accidentally left
> >too
> >> > > loose.  (A hose clamp could accidentally be left loose by even the most
> >> > > competent and honest mechanic, BTW.)  Access to many of these hoses and
> >> > > clamps is difficult and some are impossible to see.  Even if you can see
> >> > > the clamp, maybe you can't reach it.  A loose clamp may not >look<
> loose.
> >> > > You had a recent timing belt replacement... this would require
> removal of
> >> > > the intercooler and attendant hoses.  One of these clamps that you can
> >> > > barely see, let alone reach, may be loose and later the hose blew off.
> >  A
> >> > > non-turbo engine does not have an intercooler and does not blow the
> hoses
> >> > > off or rupture old hoses the way pressure form a turbo will.  Another
> >thing
> >> > > on the turbo engine which may have been disturbed during timing belt
> >> > > replacement is the wiring/connector for the intercooler temp sensor.  If
> >> > > the fragile little wires here are damaged they will short out this
> sensor
> >> > > and rob your engine of power.
> >> > >
> >> > > Did your car spend years in the rust/salt belt?  If so, this creates
> more
> >> > > problems.  Sixteen years of high underhood temps causes deteriorated
> wire
> >> > > insulation and connectors.  A poor connection on a single sensor is a
> >> > > problem.  Cracked wire insulation and hardened rubber wiring connectors
> >> > > allow salt to enter and corrode the electricals.  Access to some of
> these
> >> > > sensors and wiring is difficult.  You cannot afford to replace all the
> >> > > things on your car that could cause problems in hopes that one of these
> >> > > things will fix it.  A methodical approach is needed where a problem is
> >> > > narrowed down to it's source and dealt with.
> >> > >
> >> > > Let me give an example from recent experience with my own 89 200Q that
> >> > > improved performance...
> >> > > The real problem which prevented the engine from running was a loose
> >clamp
> >> > > on one of the intercooler hoses... one of the clamps that is hard to see
> >> > > and difficult to reach.  No doubt it was me who failed to tighten the
> >> > > clamp.  When I tested for spark it appeared to be either no-spark or
> weak
> >> > > spark.  I narrowed the problem down to the coil so I removed it to
> swap a
> >> > > known good coil to see if that would help.  It didn't help because my
> >> > > >real< problem was a loose hose clamp.  I examined the old coil and
> >found a
> >> > > surprise problem which I suspect is common on these cars.  There is
> a fat
> >> > > wire connector pushed on to the bottom of the coil.  I pulled this
> >> > > connector and found >way< too much green corrosion on it.  This wire
> >> > > connector would be difficult to examine without removing the coil from
> >the
> >> > > car, and coil R&R is not easy, so I had never examined it before.  The
> >> > > rubber connector boot here is supposed to seal out water but was
> hardened
> >> > > from old age and no longer doing it's job.  I cleaned up the corrosion,
> >> > > smeared di-electric grease around the rubber bootie and re-installed
> >it in
> >> > > the car.  Still no start.  Then I found the loose hose clamp and
> >tightened
> >> > > it.  Now the car not only starts and runs, but it starts and runs much
> >> > > better than before.  So... I had two problems... one which prevented the
> >> > > engine from running at all (loose hose), and a second one which caused
> >weak
> >> > > spark and reduced performance.  In the end I didn't install a single new
> >> > > part, but having some known good spares to swap was a big help. I also
> >had
> >> > > plenty of time to troubleshoot at my leisure since I have a spare car to
> >> > > drive at all times.  Replacement of the coil with a new one, a $200-250
> >> > > part, would also have fixed the weak spark.  If I had paid a competent
> >> > > honest mechanic to fix my weak spark I would expect it to have cost at
> >> > > >least< $300, maybe a lot more.
> >> > >
> >> > > HTH,
> >> > > Dave C.
> >> > >
> >> > >
> >> > >
> >> > >
> >> > >
> >> > >
> >> > >
> >> > >
> >> > > _______________________________________________
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> >> > >
> >>
> >>
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> >>
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