IA III Chipset Problem

[Brett Dikeman]

On Wed, Aug 19, 2009 at 12:06 AM, <ksternal at cox.net> wrote:

> At 196k attaining 1.5 -1.6 has been a pretty good sign that it was
> ready for the added stress of chipping, right?

No.

> Now difficult to achieve 1.4, and gobbling gas. Biggest symtom was teh sharp
> burp or cut-out while reving- up under load.  Archives lead to  Wastegate Spring.

I've never heard of the wastegate spring causing anyone any trouble.
The diaphram occasionally (rarely) fails, but that is easily tested
with a mityvac pump attached to the test port.  So first off, undo
whatever you did with the wastegate.  You may need to do the factory
adjustment procedure, which is in the Bentley.  In any case, adjusting
it is NOT NECESSARY.  I had the 3+, got full boost indicated, car
pulled like crazy.

How does the car start, idle, and drive when cold before the O2 sensor
warms up and the EC goes closed-loop?

1)Are there any codes?

2)Pressure test the entire system by plugging the hose off the MAF
with a 1-cup rubbermaid container.  I installed a compressor fitting
and would pressurize it slowly off a tank.  Make sure you don't exceed
1.8bar indicated on the trip computer- if you go much higher, you run
the risk of damaging the sensor.  Watch out for the dipstick, it may
pop off.  Track down any hissing noises.  Common failures: michellin
man hose, throttle body hose, crankcase breather hose.  The
intercooler inlet can also leak if the wrong o-ring is installed (BTDT
with a mechanic who thought he had one "close enough".)  Listen
closely near the back of the engine for any leaks from the various
control line hoses, and check the integrity of the line to the fuel
pressure regulator especially.  If that's broken, leaking, or off-
it'll cause a really rich idle and fuel starvation under boost (bad
news.)

3)If you suspect the WGFV, test it.  They have an resistance spec in
the Bentley, I think it's around 100 Ohms, maybe 300?  If it is much
higher, it is dead.  Apply 12v, or if you have to, 9v from a 9v
battery.  Any noise?  Can you blow through it the other way now?
Unplug the valve electrical connector and test drive.  Any different?

4)Plug in VAG-COM and see if the data block values make sense.  The
Bentley tells you want values to look for, and the specific test
conditions (engine temperature is one, for example.)  You'll want to
make sure that the engine temperature sensor value makes sense, that
the adaptation values for O2 and MAF make sense, etc.

5)How's the distributor/rotor/wires?  When was the fuel filter last
changed?  How about the air filter?  I got my new-to-me iron home (not
a 200q20v) and found the PO had apparently NEVER cleaned the K&N
filter he installed (grrr!)

If the adaptation values are way off and you've ruled out a boost
leak, the possibilities are mostly a failed MAF and a failed fuel
pressure regulator.  Gobbling fuel- how did you come up with this?
(just curious for more specific info.)

Brett