check engine light

[Brooks Ellis <brooks@frii.com>]

[ the 89.5 200Q ]

>If it is the Hall sender malfunctioning, the car usually wouldn't start. 

Why is a hall field sensor neccesary anyhow? To control the ignition
sequencing in a more precise way? I'm really not very familiar with the
newer engines (in a technical-repair sort of way). 

>What I think it is is maybe the exhaust manifold stud(s).  I think 

What's wierd, is everything has been kicking ass, and then one night, out
of the blue it started the 'emission control system' (check engine) light
when I exceeded 3000 rpm EXACTLY. The light would pop on right above 3k,
and when I let the RPMs drop, as soon as the RPMs dropped below 3k, the
light popped off. 

I didn't experiment with high-load or WOT, because I was concerned that
something fragile was on it's way out, and didn't want to hasten it's decline.

I'm going to check with the local Audi dealer (-great- service, really
good. I know people that drive 300 miles to get their audi's serviced here.
A little pricey because it's a dealer, but it may be worth it) and see what
they have to say about it. I'm not sure if I can get ahold of them, because
their building half burnt down a few days ago.. :( Aside from structural
damage, four (4!) cars burned up, with a total value of $125k..! (they do
porsche, VW also).

While I'm there, I'm going to get an Audi key made with the little light..
:) I really like those keys.

I'll experiment a bit tomorrow, then do the dealer thing.. maybe it was
just a one time gremlin. It's happened before.. See if I get full boost or
not - will the solenoid make the wastegate open early if it thinks
something is wrong (in your modded chip)? I've got a couple other questions
on your chip, but I'll worry about that after I get things stabilized first. 

Thanks everyone for helping me out! (not to mention reading my odd posts to
the list:)

brooks

P.s. What do the knock sensors look like? I couldn't locate them at a
cursory inspection of the engine bay.