What is the deference between {GM.MANVAC} and {SAE.MAP}?

[odd boy]

Gents,

What is the deference between {GM.MANVAC} and {SAE.MAP}?

This question leads to other questions:

1. If {B4001} stores the fuel flow rate values and {B0101} contains the air flow rate to each cylinder, do both work together to calculate the AFR or the AFR is being calculated based on the commanded {B3605}/{B3618}?????

2. Since the PCM has the air flow rate, the fuel rate, as well as the commanded AFR, so what the PCM calculates?

3. if {B5001} gets in the picture (i.e the engine speed exceeds {B0120}, how we can imagine Hz in terms of something tangible like RPM so we can make connection between {B5001} and other tables…etc?

[joecar]

OB,

MANVAC = BARO - MAP

BARO is what the MAP shows at key on engine off.

B0101|B5001 are used to calculate the airmass;
B3605|B3618 are looked up to get commanded AFR in OL/WOT; if CL, then commanded AFR is B3601;
Fuelmass is calculated from commanded AFR and airmass;
B4001 is looked up to get IFR at the current MANVAC;
Injector pulse width is calculated from IFR and fuelmass.

The connections bewteen various tables may be provided by pids such as CYLAIR, DYNAIR, DYNCYLAIR, MAP, etc...

Each table lists the "link" pids it requires... if you log these link pids, then you can link directly from scantool log to tunetool table.

Cheers,
Joe