[s-cars] Exhausting Morning

[tedebearp at yahoo.com]

Check your fuel pressure regulator.  If it's original, consider replacing it anyway, or at least verify with a fuel pressure gauge.  I was trying to track down a rich condition that cost me a set of cats and caused me to fail emissions, and I tested the FPR with a Mityvac.  It held vacuum, there was no fuel in the vacuum port, and the FPR actuated when vacuum was applied, so I thought it was OK.  I ran out of time and took the car to the shop.  It turned out that the FPR was bad and the fuel pressure was too high.  I could have replaced that FPR for $32, but instead ended up spending $300 for the shop to diagnose and replace the FPR.

Sent from my iPad

> On Feb 4, 2014, at 8:38 AM, Tom Green <trgreen at comcast.net> wrote:
> 
> Paul,
> 
> Now that you have "found" quattroworld's UrS4/UrS6/S2/RS2 forum, you can ditch this archaic method of getting timely answers.  Your issue there will be the opposite problem;  The
> sheer volume of information will be difficult to keep up with and sort out relevant threads.
> 
> This thread may be helpful as well since it sounds like your cat may be shedding the parts:
> 
> http://forums.quattroworld.com/s4s6/threads/24025.phtml#272620
> 
> You should link with Jeff Postupack through your post on QW.  He is the middleman who has organized group buys from Stromung for the UrS car owners-the only way it is possible to buy one.
> He has been involved in the development of the exhaust as well, and for the improved generations.
> 
> The good news is that the exhaust is indestructible except for the cat substrate as I suspect you are seeing.  The point being made by the other suggestions on the list is engine tune is the primary cause of cat failure, either from excessive oil burning (actually not burning, but passing into the exhaust from some source and causing the cat to have to burn it.  This coats the substrate with compounds in the oil and overheats it as well) or engine tune problems allowing excess unburned fuel to pass into the exhaust.  The change in sound of the exhaust and rattling indicates the cat substrate has broken up. Usually tapping the cat will give confirmation that something is loose in there.  Then it is a simple job to cut out the old and do a quality weld job on a new cat.  Some additional investigation to find the root cause is probably justified.
> 
> If the exhaust has gotten too noisy over the years, the mufflers can be repacked.  The casing should still be good as well as the pipe.  Maybe shine up that exit tip while you are at it.  : )
> 
> Tom '95 S6
>         '95.5 S6 avant
> Knoxville, TN
> 
> OnTuesday February 4, 2014, at 10:11 AM,Paul Luevano <paul at clarity.net>  wrote:
> 
>> Peter Schulz wrote:
>>> Paul:
>>> 
>>> Check your 02 sensor -
>>> seems like your car is running rich and some carbon is getting ejected?
>> 
>>    O2 sensor is < 2 years old.  I'll pull codes, but is *sounds* like
>> there is something loose in the exhaust.
>> 
>>    Thanks.
>> 
>> Paul
> 
> 
> 
> _______________________________________________
> S-CAR-List mailing list
> http://audifans.com/mailman/listinfo/s-car-list
> http://www.audifans.com/kb/List_information