[s-cars] Short term rough idle - follow-up

Robert Myers bob at chips-ur-s.com
Mon Jan 25 16:08:27 PST 2010 

Dave,

The most noticeable symptom is a slightly rough idle which smoothes 
out nicely in just a few seconds after start-up.  I wouldn't really 
describe it as a miss.  The rpms are pretty solid.  It's not 
"seeking" like what usually happens with a sticky ISV.

The engine sports a nice RS2 EM.

Bob


At 07:00 PM 1/25/2010, djdawson2 at aol.com wrote:
>Bob,
>I dont' really agree that you are just guessing when you see those 
>types of compression numbers.  I'd also argue the #5 cylinder is 
>where you are going to see to most heat (not #3), especially if not 
>equipped with a good EM.
>
>The bottom end of these engines tend to be very durable.  You're not 
>going to typically see a "miss" as a result of bad rings/cylinder 
>walls either... a "miss" (assuming your fuel and ignition systems 
>are working properly) is typically a symptom associated with 
>valve/valve seat wear... therefore, not sealing as well.
>
>Having a fresh head ready is always convenient on a high mileage car 
>(porting... no way).  But yours looks pretty healthy.
>
>Dave
>
>
>
>-----Original Message-----
>From: Robert Myers <bob at chips-ur-s.com>
>To: Cody Forbes <cody at 5000tq.com>
>Cc: S-Car-List at Audifans.Com <s-car-list at audifans.com>
>Sent: Mon, Jan 25, 2010 4:34 pm
>Subject: Re: [s-cars] Short term rough idle - follow-up
>
>
>*This message was transferred with a trial version of CommuniGate(r) Pro*
>
>
>
>Hmmm... Sales pitch? Have a nice AAN just sitting around waiting for
>
>a suck.. er..., customer? ;-) Uh...  How much?  :-D
>
>
>
>
>
>At 02:29 PM 1/25/2010, Cody Forbes wrote:
>
> >*This message was transferred with a trial version of CommuniGate(r) Pro*
>
> >Nah, I'd say it's fine. Cylinder 3 runs the hottest and seems to wear
>
> >a bit more, but your numbers are reasonable. Without a leak down test
>
> >any statement as to why that cylinder is low (piston rings, grouved
>
> >cylinder wall, dirty/bent/burnt valve, head gasket, etc) is just a
>
> >wild guess at best.
>
> >
>
> >Time to take apart a running car? No.
>
> >
>
> >   Time to casually search for a spare cylinder head to have rebuilt
>
> >(and ported hehe) and ready to swap on to the car on a lazy weekend?
>
> >Probably. Even better of course would be the same plan with a whole
>
> >fresh, tweaked, engine going in. Then sell the old stuff when you are
>
> >done and recoup some cost.
>
> >
>
> >-Cody (mobile)
>
> >
>
> >On Jan 25, 2010, at 1:37 PM, Robert Myers 
> <<mailto:bob at chips-ur-s.com>bob at chips-ur-s.com> wrote:
>
> >
>
> > > *This message was transferred with a trial version of CommuniGate(r)
>
> > > Pro*
>
> > >
>
> > > Yeah, Cody. You're right and I screwed it up.  Now the question
>
> > > remains - do I need to get a new head gasket and/or valve job on the
>
> > > car?
>
> > >
>
> > > Bob
>
> > >
>
> > >
>
> > > At 12:46 PM 1/25/2010, Cody Forbes wrote:
>
> > >> *This message was transferred with a trial version of CommuniGate
>
> > >> (r) Pro*
>
> > >> Note that the compression gauge has a one way valve - it doesn't hold
>
> > >> pressure in the cylinders, only in the hose for the gauge.
>
> > >>
>
> > >> -Cody (mobile)
>
> > >>
>
> > >> On Jan 25, 2010, at 11:28 AM, Robert Myers 
> <<mailto:bob at chips-ur-s.com>bob at chips-ur-s.com>
>
> > >> wrote:
>
> > >>
>
> > >>> *This message was transferred with a trial version of CommuniGate(r)
>
> > >>> Pro*
>
> > >>>
>
> > >>> Original post:
>
> > >>>
>
> > >>> Hi Y'all,
>
> > >>>
>
> > >>> My well modified '95.5 urS6 has developed a relatively minor but a
>
> > >>> bit disturbing problem.  On initial start-up the engine idles a bit
>
> > >>> roughly.  The idle smoothes out again after a few (perhaps 10-15)
>
> > >>> seconds and becomes as solid as a rock.  Obviously this is not, of
>
> > >>> itself, a major problem but it could be a portent of something more
>
> > >>> serious to come.  Any ideas/suggestions?
>
> > >>>
>
> > >>> Other than the idle problem the car is running superbly.   Let's
>
> > >>> see...  modifications which might be related...  Running the Dave
>
> > >>> Forgie 1.8t coil mod as expressed by Apikol.  All the RS2 mods -
>
> > >>> turbo, ECU, EM, injectors.  Stromung exhaust.  Big FMIC, etc.
>
> > >>>
>
> > >>> Bob
>
> > >>>
>
> > >>> And now the follow-up:
>
> > >>>
>
> > >>> There were several suggestions ranging from "don't worry about it"
>
> > >>> to
>
> > >>> "try some Techron" to "check out the ISV" to "uh-oh might be a blown
>
> > >>> head gasket".  (Oh joy.  :-()
>
> > >>>
>
> > >>> OK, here's what has been done since the first post:
>
> > >>>
>
> > >>> Item 1 - a can of Techron has been added to a 3/4 full tank of fuel
>
> > >>> and about half of it has been burnt.
>
> > >>> Result 1: idle is smoother.  Not perfect yet but improved.  (It
>
> > >>> wasn't REAL bad to start with so...)  Indicating possible dirty
>
> > >>> injector(s).  I'm planning on doing the Techron bit again the next
>
> > >>> time I fill the tank.
>
> > >>>
>
> > >>> Item 2 - I pulled and inspected all the NKG plugs.
>
> > >>> Result 2 - They all looked the same - dry and with normal
>
> > >>> coloration,
>
> > >>> no excessive wear.  They looked as good as any plugs of that age
>
> > >>> in a
>
> > >>> big boost I5.  There is a hint of black deposit on the threaded
>
> > >>> portion of #1 well outside the internals of the engine area.  It
>
> > >>> is a
>
> > >>> little greasy feeling and left a smudge on the fingers.
>
> > >>>
>
> > >>> Item 3 - The symptoms don't seem to indicate ISV troubles to me so I
>
> > >>> haven't messed with it (yet) - I will if the problem persists.
>
> > >>> Result 3 - none (yet).
>
> > >>>
>
> > >>> Item 4 - While the plugs were out I checked the compression of each
>
> > >>> cylinder (only one try - no repeated testing and averaging, cranking
>
> > >>> time was the same for all cylinders twelve pulses per cylinder) and
>
> > >>> found:
>
> > >>> Result 4 -
>
> > >>> Cylinder    max pressure
>
> > >>>  1          150
>
> > >>>  2          150
>
> > >>>  3          135
>
> > >>>  4          160
>
> > >>>  5          155
>
> > >>>
>
> > >>> Additionally after cranking the gauge was just left alone while
>
> > >>> still
>
> > >>> connected to the cylinders.  The pressure held and there was no sign
>
> > >>> of leakage - at least not in the short term (a couple of minutes).
>
> > >>>
>
> > >>> I'm not thrilled with #3 pressure but it is pretty close to being
>
> > >>> acceptable.
>
> > >>>
>
> > >>> OK, whadya think?  Should I be making an appointment with my
>
> > >>> favorite
>
> > >>> independent Audi wrench or should I just quit picking at nits and
>
> > >>> get a life?
>
> > >>>
>
> > >>> Bob
>
> > >>>
>
> > >>> _______________________________________________
>
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>
> > >>> 
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>
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>
> > >
>
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>
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