air-fuel and knock

[Brett Dikeman]

At 2:56 PM -0400 8/11/04, Nick Lawrence wrote:
>Intended vehicle is 5cyl Audi, either NA or turbo.
>
>Does anyone have any experience with add on air-fuel ratio gauges, 
>such as autometer, edelbrock, s-w?
>Are they accurate enough to be safe?

They're just O2 sensor meters.  Some ($$) are wideband.  Store-bought 
O2 sensors are not considered instrument grade- instrument grade O2 
sensors cost $$ and wideband instrument grade ones cost $$$.

Everyone I've heard talk about O2 meters says they are "cool" for 
about an hour or two, and then they transition to "annoying" very, 
very quickly.

>Is there any way to monitor knock sensor activity? Besides waiting 
>for a stored code.

Yes, timing will be altered if there is knocking, and on some ECUs 
the VAG-155x, Prodiag, or VAG-COM will be able to see this in the 0 
block, which has a value for current timing angle.

   A code will only be stored if the ECU is unable to regulate the 
knocking- not if the engine is requiring constant intervention by the 
ECU (such as being run off improper gas, excessive carbon buildup, 
poor tuning/mods, etc).  Further, a code will only be "stored" on 20v 
turbos or newer engines; the 10v's all had non-permanent fault code 
memory and the code will be gone once the engine is shut off.

Brett
-- 
"They that give up essential liberty to obtain temporary
safety deserve neither liberty nor safety." - Ben Franklin
http://www.users.cloud9.net/~brett/