[V8] Ecu code, cats

[Jeremy Ward]

Hmmm.  I know the 4.2 has a different setup than the 3.6 and you have to do
a 'trick' when you transplant one (but I don't know what that is...)  I
believe the ABH uses an EGR setup, there the PT just has a charcoal
canister.  Anyone care to comment?

On the 3.6, you have 2 vacuum lines coming off of the throttle body; one
big, one small.  They both go over and disappear under the coolant
reservoir, into a frequency valve / diaphragm thingy (I am sure that is the
technical term they use in the manual!)  The big goes into the end closest
to the firewall, the small goes into the bottom of it.  There is an
electrical connector (looks like a 2 or possibly a 3 wire hookup).  Lastly,
there is a 3rd (same size as the large input) line that goes to the charcoal
canister.

There is also a vacuum line coming off the rear of the engine that controls
the climate control - specifically opens and closes vents with its vacuum
power.  This one shouldn't have any thing to do with your issue, but if it
is totally disconnected the dash vents work funny and the car also stumbles
at idle.

A few years back, I replaced all of the vacuum hoses and put hose clamps on
both ends of each hose.  I think this set me back a whole ten bucks and made
a big difference.  If you have a vacuum leak, then your mileage will be in
the toilet, car will stumble on idle, and the ISV may throw a code because
it can't keep up with the huge loss in vacuum.  You will also hear a
distinct 'whistle' to let you know you have a vacuum leak. ;-)

If you need pictures, let me know and I can shoot them tonight.

Good luck!

- Jeremy
www.MyV8Q.com 

-----Original Message-----
From: v8-bounces at audifans.com [mailto:v8-bounces at audifans.com] On Behalf Of
Coleman, David
Sent: Thursday, September 01, 2005 1:20 AM
To: v8 at audifans.com
Subject: [V8] Ecu code, cats

Ok it's now 3:ep am eastern. Here's what I've worked thru:

That 2324 (ecu ground, bad ecu) still there. I checked black plastic doodad
hanging from the 2 vac lines. Manual shows it as 1/2 of the frequency valve
/ control for the carbon canister. Other half still suspended by 2 spubbies
in the r/s fender. Maybe a vac leak and I'm good. Refit the halves together,
start car, no diff -- barely idles, falls flat under heavy-ish throttle
input (bad cat symptom), black/grey smoke out pipe, and odorless sooty water
spritzing out the pipe. 

So I do the output tests (fuses good): all 8 injectors click away, ISV
clunks open/shut, move to charcoal canistertest and nothing. Correct 4431
blinking out but no indication the canister is actuating. Hand on
freq/control solenoid feels nothing. Though sjm says canister is "behind &
under cyl head", only thing I see there is exh manifold. Bentley puts it
behind r/f fender, which makes sense with hose disappearing back up there.
Reach up as far as I can, no canister or sense of actuation.  Meanwile the
isv making a humming noise. Whatever, last output test shows cleared ecu.
Redo procedure, same result. I trace the freq valve solenoid wire and find a
breach where they'd been rubbing against a surge tank bolt. 
Cut back sheathing back and wrap wires in elec tape.  Start up, no diff,
same 2324 code. Run output tests again, and still no faint indication of
canister actuating, and I'm not pulling the fender liner in search of it
tonight. 

Start car, same deal. Test light shows power at freq valve connector. While
there unplug ECT sensor behind head and car dies. Restart, now throws 2231
ISV, which tests good at connector. But ECT connector shows NO power. 

It's late. Todo: check proper ecu pin(s) for ect. Pull O2 wire out, and swap
in used isv, maybe MAF too.

If you made it this far, please feel free to chime in especially re: no ECT
power.  Sure CAT situ needs sorted, but really looks like another issue is
at hand..

I heart feedback

DaveC.





--------------------------
David A. Coleman
BlackRock
Sent via BlackBerry Wireless


THE INFORMATION CONTAINED IN THIS MESSAGE AND ANY ATTACHMENT MAY BE
PRIVILEGED, CONFIDENTIAL, PROPRIETARY OR OTHERWISE PROTECTED FROM
DISCLOSURE. If the reader of this message is not the intended recipient, you
are hereby notified that any dissemination, distribution, copying or use of
this message and any attachment is strictly prohibited. If you have received
this message in error, please notify us immediately by replying to the
message and permanently delete it from your computer and destroy any
printout thereof.
_______________________________________________
Audifans V8 mailing list
Send posts to: mailto:V8 at audifans.com
Manage your list connection: http://www.audifans.com/mailman/listinfo/v8
Have an Audi V8 question?  Check the Audifans Knowledgebase!
http://www.audi-quattro.org/cgi-bin/twiki/view/Audi/V8
Have a V8 answer? ... Please help others by adding to the KB ... all
contributions welcome!