P0101 ...wanted delay in MAF reaction

[ar99kid]

Condition : the MAF is relocated from 3 feet away right know is in front of throttle 4" ( my intake through the hood scoop).

because of this my MAF is reacting instant exactly like the TP ! i have logged and watched in the "osciloscope" dash page the TP , dynair g/s and MAF g/s. my observation is that TP and MAF are going exactly the same (graphic speaking) and the dynair is different for a fraction of time especially when TP suddenly moves. my thinking is that this appears because i don't have any air inertia the MAF being so close to the throttle and any rapid change in TP it isn't compensated by the ECU in the dynair . the dynair has a delay in reacting at instant move of the TP. you can see the yellow line on the graph is a little behind the TP and the MAF . and because of this i am getting p0101. right know i am only thinking of increasing the MAF rationality test ...

i am working right know on the c2911 table to increase very large amount from what scan tool is telling me , but i would like to know if there is a calibration that could delay the MAF readings ? something to give me more "air inertia" like the MAF would be seating farther away and don't have that instant readig like the TP is moving ...just for a fraction of second ...

is this possible ???

i have put some printscreens to be more easy to understand...

thanks for looking !

[swingtan]

None that I know of. Careful work in C2911 is required on any car that is still running the MAF as a decent tune coupled with some minor bolt on mods will see the rationality tests fail. I've had issues with just a tune and a full exhaust, but after adjusting this table ( E38 equivalent ) it's all good. One thing to note about this "Hi Speed" MAF reaction is that it can help with transients. The sudden spike in MAF airflow allows the engine to add transient fuel quicker. This probably isn't an issue with an automatic car, but manuals will see the effects on gear changes.

Simon.

[joecar]

My understanding is that DYNAIR is computed based on the VE table...

If DYNAIR lags then either the VE table is not correct or the MAP sensor response is slow...

or, maybe the CKP sensor (RPM signal source) is slow... ugghh... this can point to CKP reluctor freewheeling/walking problems... are you able to rev the engine above 4000 RPM...? Is this the Hummer...?

[ar99kid]

thanks guys for your inputs

i was hoping that there will be such thing...but i guess not. anyway , after playing with c2911 with some large values right know i don't have any more p0101. so this will be for the moment

joe...yes i can rev this over to the end about 5800-6000rpms. and i will take another autoVE because it is a little warmer here...last week were about -10C -15C very cold. this time i will take a much longer trip in 2nd and 3rd gear to try to have a better table

thanks for looking