smog rack redux ('93 v6-12v)

[Fred Munro]

Hi William;

NOx is generated at high combustion temperatures and the output peaks as the
mixture leans out past the stoichiometric ratio of 14.7:1. Judging from your
tests, you could afford to richen up the mixture slightly to drop the NOx
since you have room in CO and HC. I'd look for an air leak which is causing
the car to run lean.
The cat does reduce NOx, CO, & HC, but if you have vacuum leaks you may not
need new cats.

Good luck!

Fred Munro
'94 S4  112k km

----- Original Message -----
From: "William Magliocco" <magliocc at rocketmail.com>
To: <quattro at audifans.com>
Cc: <v6-12v at audifans.com>
Sent: Monday, October 02, 2000 12:58 PM
Subject: smog rack redux ('93 v6-12v)


> I'm singing the "4444" blues.  The car is still sick
> but the ECU is singing a different tune.
>
> Score thus far:  Smog Rack 2, Bill 0.
>
> 1)  Test results, 1st visit (9/26) & second visit
> (10/2) , limit
>
> HC-ppm:  98, 95, limit 117 PASS BOTH
> CO-%: 0.29, 0.24, limit 0.65 PASS BOTH
> NO-ppm:  1171, 0946, limit 0821 FAIL BOTH
> CO+CO2%: 14.2, 14.6, min 6.0% PASS BOTH
>
> Same machine did the tests.
>
> Over the weekend:
>
> two new o2 sensors, 6 new Bosch Platinum +4 plugs and
> replaced a cracked vacuum line coming off the intake
> manifold
>
> Decided to visit Mr. Midas.  Believe or not, the
> manager did not try to sell me cats!  His generics
> won't fit.  He also felt that the engine could be
> massaged by the local smog guru tech for less than the
> cats.  Doesn't think the cats are bad.
>
> Smog guru didn't want to discuss much with me after
> looking at the test reports.  Wants me to drop it off
> and pay the $75 etc.
>
> What confuses me is that both of these "MLs" seem to
> think timing is an issue.  OK, I have distributorless
> ignition so they can't rotate something that's not
> there.  This engine is so highly controlled that I
> wonder just how much CAN be adjusted.  After all,
> there is no CO control and the Federal/CA label
> indicates there are no adjustments.
>
> Paying someone $75 to tell me the cats are bad seems a
> waste.  When I made noises like that, the guy got
> pissed.  Says he's from Detroit and does not like
> "furrin" cars anyway.
>
> OK, gallery, give it another shot.
>
>
>
>
>
> __________________________________________________
> Do You Yahoo!?
> Yahoo! Photos - 35mm Quality Prints, Now Get 15 Free!
> http://photos.yahoo.com/
> _______________________________________________
> Quattro mailing list Quattro at audifans.com
> To remove yourself, change to digest mode, or temporarily stop delivery
> please visit the web interface at
> http://www.audifans.com/mailman/listinfo/quattro
>