REP mode turbo 5.3 base tune, explain airflow deltas?

[gravedigger472]

2010 Silverado 5.3, Trick turbo 76mm turbo, comp stage 2 VVT cam, Deatschwerks 72lb injectors E38 ECM

Made a base tune from my old N/A tune, pulled a bunch of timing, updated injectors with info from Deatschwerks site. The truck is tuned in MAF mode, and AFR is fairly close. When the turbo starts to build positive manifold pressure I get REP mode with P0068, P0101, P0121.

I am fairly sure what is happening is the measured airflow is exceeding a preset threshold, so so the ecm sets the code and goes into REP mode. I can disable the code entirely by raising temp and rpm, but I would rather raise the airflow threshold.

I tried raising 14042 Max Airflow vs RPM by about 50%, to a value higher than logged when REP kicks in, and it still comes on.
Also raised 14043 Max airflow vs IGN volts, same result; REP mode.

Next step is to raise the airflow delta, but not sure the function of the tables. Can someone explain the function of table 14044 and 14045 the "airflow delta" tables? What is the delta between? Should I just raise the values?

Tune file attached.

turbo tune_007.hpt

[TitanTuned]

Did you ever figure out how to resolve the issue?

[Alvin]

This is typically because the airflow measured by the MAF is far higher than the VVE. It's ok to modify the tables that set that diagnostic for the new setup.

[verlon]

Did you ever figure out how to resolve the issue?

E38/E67 has the following airflow sources:
1. MAF sensor
2. VVE airflow estimation
3. Throttle airflow estimation
All of them must correspond to each other.

VVE and Throttle models are reversible and used to estimate MAP assuming MAF as reference airflow. So we have pressure sources:
1. MAP sesnor
2. VVE pressure estimation
3. Throttle pressure estimation
All of them must correspond to each other too.

When MAF and MAP sensor are failed simultaneously two models (VVE and Throttle) are used together to estimate MAP and consequently airflow.

In this scope the crucial moment of the E38/E67 ECMs is the throttle inlet pressure (TIAP) estimation used for the Throttle model. It is BARO pressure with intake duct pressure drop correction. Intake duct model is represented as simple effective area in the calibration which can easily be found in the [Engine Calibration] segment and is usually have a value of 5000 mm^2.
When you are blowing unexpected (to the ECM) pressure to the throttle inlet it's model calculation fails as it get inlet pressure = BARO and after throttle pressure is higher than BARO, so calculated throttle airflow is NEGATIVE, but limited to zero. The same thing happens with Throttle MAP estimation: inlet pressure = BARO and huge airflow, so calculated Throttle MAP going towards zero.

There is no way to correctly overcome this situation on those ECMs except patching OS to tell ECM real TIAP using one of the available pins for the boost pressure sensor. Or just disable those DTC tests.