[A4] 16806 cat issues?

Aaron Jongbloedt jungle at hickorytech.net
Thu Mar 29 04:19:51 EDT 2007

Thanks...I will try that....slow and incomplete spool is pretty much it....I
forgot to mention that the car usually boosts like 18psi...now it struggles
to reach 12psi......I have put on about 15k on the car, and this is the 1st
time w/ THIS code....


From: Brizax at aol.com [mailto:Brizax at aol.com] 
Sent: Thursday, March 29, 2007 12:46 AM
To: jungle at hickorytech.net
Subject: Re: [A4] 16806 cat issues?

if you suspect its the cat plugged, just loosen it at the turbo completely
and take it for a quick boost  and see if the power is back, dont run it
more than 1 or 2 pulls because the hot exh gas leaking at the flange will
melt anything around, 1-2 quick pulls wont hurt, however i think the code
your getting means the cat is not working as if the previous owner empty'd
it possibly? a clogged cat will spool very very slow!


The short version of this story is....
I had this car for just over a year now...
1.8t KO4 mtm, 120k on it...
all this work was done about 15k ago...refurbished head, spark plugs, 
n75F, Saab diverter valve, new PRIMARY O2, new coolant temp sensor, new 
t-stat, new MAF

I have never seen above 24.5mpg, even on road trips.....during a dyno 
run it pulled a mere 170hp, and the a/f ratio dipped into the 11's...(i 
have the plot somewhere on line)....I have tested for vacuum  leaks time 
and time again....Early last week i noticed a big lack in power, and the 
max boost has dropped from 18psi down to 12psi....then yesterday it 
pulled a CEL.  "16806 Main catalyst bank 1 below efficiency threshold". 

I did some looking on Audi World and Vortex....and as usual there are a 
plethora of choices.....I am leaning towards a partially plugged cat, 
considering the age of the car, and considering how rich it runs....does 
anyone want to offer up any suggestions before i plunk down $300 on a 
new cat?  

Speaking of which I am thinking about TT's cat...it is $300 w/ all the 
hardware....it has a rating of 400cel's and the oem one is roughly 650.  
I am also debating about doing the downpipe as well for another 
$225...seeings i am in there type deal...any thoughts?




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