Injection Quantity

[muddyboots]

Something else I noticed while playing with vag-com....

I did a few full-power runs in 3rd gear last night, logging various different blocks in the engine module, to get a feel for how things are running.

I forget which block it was (12 or 13??) but it contains the following readings:
1) RPM
2) IQ (driver request)
3) IQ (rpm)
4) IQ (MAF)

Am I right in thinking the Injection Quantity (IQ) used is the lowest of the 3 values ?

Throughout the full-power runs, the driver request IQ sat at 70mg, presumably related to my foot being hard on the floor. The MAF IQ was always the highest figure, but the rpm IQ was only just under.

Does this mean the MAF is saying there's enough air coming in to burn slightly more fuel, but the fuel/rpm mapping is not taking full advantage (only a tiny difference though) ?

Interesting sutff, in a geeky way

 

[EdButler]

I have no idea about this measuring block matey as i always use Block 15 to check injectors which measures:

RPM
Inj Qty (Actual) - mg/r
Fuel Consumption - l/h
Ing Qty Requested (Accellerator) - mg/r

Its pretty easy on these two to find out when the injectors are max'd out (70mg/r). I dont have a clue about the RPM and MAF versions tho mate

 

[muddyboots]

I remembered reading a post a while back from Nic (Cheshire Cat) about his mod to remove the MAF and replace it with a diode. At the time I didn't really understand how that could work, but if the ECU does use the lowest of the three IQ request quantities, replacing the MAF so it always provides a max IQ request means you would only be limited by the IQ/rpm mapping.

It all makes a bit more sense now.

 

[sssstew]

Am I right in thinking the Injection Quantity (IQ) used is the lowest of the 3 values ?

Does this mean the MAF is saying there's enough air coming in to burn slightly more fuel, but the fuel/rpm mapping is not taking full advantage (only a tiny difference though) ?

yes, this would make sense on both counts.