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

[Cody Forbes]

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 <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 <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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>