Neo1130

I am having some troubles, pictured below... I am getting low requested boost... I have a 2001 with GIAC X and USED to boost about 20-22 psi and hold 18... Well, I cannot even get the ECU to request anything above 16 psi and hold 12ish... Anyone know what would cause the car to pull boost? I am starting to think my cat is going but I don't have a CEL nor do I think that a clogged cat would cause low request, would it?

<img src="http://www.audizine.com/gallery/data/500/Boost2.jpg">

Neo1130

Hints? Tips? Clues? Anything?

diagnosticator1

calculation as needed to achieve the target torque output. The "requested" value is a result of the specified load, and other parameters of the torque demand based engine management system strategy.
Causes for the ECU to reduce spec boost, are excessive high IAT, detection of combustion knock/pre ignition/detonation, excessive high coolant temps, and high altitude driving.

Neo1130

My IAT's are reaching 55 max, I am running 10.8 AFR, coolant temp never reaches above 92 and I am at sea level... There is 1.2% for altitude correction... Engine load was around 180%...

I did find today that my coil on #4 went bad... Could a bad coil cause this? I am getting 4 new ones tomorrow...

diagnosticator1

If the connections to the knock sensors is loose, or otherwise a poor connection, and there is false knock activity recognition, then the sitation would be reflected by the knock correction ignition timing retard. The ECU also must filter out stray vibrations from rough roads etc as part of the knock recognition. Loose engine mounts or other sources of vibration/noise that the sensors are tuned to be sensitive to may be involved, not likely, but something to consider. If the ECU ignition timing retard does not stop the knocking symptoms then boost is reduced and fuel mass increased.

Neo1130

I got 0 across the board for my CF's... I went into lemmiwinks since I knew I was in a safe zone to advance some timing... I had to advance my timing up to 8 degrees for it to even register a CF...

diagnosticator1

How did the car run with the timing offset +8 degrees?

Neo1130

GIAC said it was hardware, car didn't fell any different...

diagnosticator1

and is a main aspect of achieving the torque output target value, based on the ECU programming maps and measured values of MAF etc, it's not a hardware Dependant variable like the actual boost pressure achievement is.
So, I would recommend you ask GIAC to explain the alleged association of "hardware" as the source of the low specified boost in your situation. Aside from the fact the spec. and actual boost are low compared to before, the relative values of specified and actual boost logged, are within normal limits. You can check the manifold/boost pressure sensor just to confirm that it's OK, by applying a known pressure to the sensor using a pressure gage and an air pressure regulator, supplied by compressed air source, and comparing the output signal or pressure as interpreted by the ECU, viewed by VAG-COM.

Neo1130

and am waiting for the results on that...