Desired Airflow Question, not your normal question

[Gelf VXR]

The PCM accomplishes that by computation using engine displacement, engine speed and MAP sensor readings.

Ok, its using the RPM and MAP sensors, and the main VE table.

[dfe1]

Ok, its using the RPM and MAP sensors, and the main VE table.

No, if I understand your original question correctly, the VE table is not a consideration. When you asked about the amount of air flow you need, I assumed your question was in reference to the "Desired Air Flow" table (B4307). If that's the case, that table has to do with the amount of air required for idle. The entries in this table typically have to be adjusted when a long duration camshaft is installed or any other modification that significantly alters idle air flow characteristics is done.

[Gelf VXR]

No, if I understand your original question correctly, the VE table is not a consideration. When you asked about the amount of air flow you need, I assumed your question was in reference to the "Desired Air Flow" table (B4307). If that's the case, that table has to do with the amount of air required for idle. The entries in this table typically have to be adjusted when a long duration camshaft is installed or any other modification that significantly alters idle air flow characteristics is done.

I never asked the question, but there is a long and short answer. When the MAF is not funtional how does the PCM know how much fuel to add.

Short answer, it uses the main VE Table.

Long answer, by looking at the VE Table, it will tell you it uses RPM sensor and MAP sensor, if you look at the funtion for VE it will tell you it references temperature and uses IAT sensor and ECT sensor, etc.

[Dale]

When the MAF is not funtional how does the PCM know how much fuel to add.

There never was a question on how does the pcm know how much fuel to add.

The question was about Desired Airflow.

[Gelf VXR]

But its relevant