MAF low performance after cam tune (P0101)

[outsiders]

hello-

just installed a camshaft in my LS1 and got it tuned by my tuner. my fuel curve wasnt pretty, and it was leaning out quite a bit at the end. i was also getting a CEL for p0101, MAF low performance.

from what ive gathered, this is a code that gets set when MAF values do not meet coded value for MAP (ie SD). the pcm does a "rationality check" against Speed Density values to check the MAF. when these values exceed Maximum Delta Airflow, it illuminates the CEL and possibly puts the car in Speed Density as a safeguard.

my question is, is this from VE tuning, or MAF tuning? does the Delta threshold need to be larger? is there something he missed?

I was told that he had messed with the MAP tables to try and combat low vacuum made by the camshaft, but after the CEL was set, he flashed them back to stock to no avail.

the car idles rough and fueling WOT is not what id like it to be (ie flat), but the car drives okay. my tuner says that the Maximum Delta Airflow shouldnt have to be touched.

any ideas? i do not have any tables, logs, or files to show you.


thanks in advance.

[Street Legal]

just increase the value of the maximum delta airflow under engine diagnostics by multiplying the table by 1.3

[jegten]

what would be the particular reason for someone using max value on that table?

[outsiders]

just increase the value of the maximum delta airflow under engine diagnostics by multiplying the table by 1.3

my tuner has said that he has never had to do that before with much larger camshafts. what exactly is the reason for changing the maximum delta airflow? Maf doesnt match up with Speed Density at certain RPM plots? can the SD/MAP tables be manipulated to fix the error without changing the delta? or is raising the delta not considered a bandaid?

does this mean the VE tables are not set correctly or dirty? would changing the MAF tables instead of the VE negate having to do this?

does the PCM infact rely on MAF 100% after 4000rpm? would having this code (p0101) infact cause the PCM to calculate fuel in SD at WOT, therefore not fueling favorable for dyno tuning?

just trying to get my fuel curve more favorable and perhaps find some missing hp/torque.

[outsiders]

i failed to mention that this code is triggered immediately after starting the car.

[outsiders]

nobody has any ideas?

[Street Legal]

this is the code discription if you are intrested ..just double the air flow delta and you will be fine..

The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore. The frequency varies within a range of near 2,000 Hertz at idle to near 11,500 Hertz at maximum engine load. The PCM uses the following sensor inputs to calculate a predicted MAF value:


The manifold absolute pressure (MAP) sensor
The intake air temperature (IAT) sensor
The engine coolant temperature (ECT) sensor
The engine speed (RPM)
The PCM compares the actual MAF sensor frequency signal to the predicted MAF value. This comparison will determine if the signal is stuck based on a lack of variation, or is too low or too high for a given operating condition. If the PCM detects the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value DTC P0101 sets.

[jegten]

so, multiply by 1.3 or double it? thanks!

[outsiders]

how can i make MAF pass the rationality test without changing the maximum delta airflow values? it needs to match SD or the calculated MAF, right?

[2xLS1]

just increase the value of the maximum delta airflow under engine diagnostics by multiplying the table by 1.3

I'm the tuner and in well over 100 cam tunes from mild to wild I have never had to change that table from stock. This is the 1st 04 GTO cam tune though, so maybe it has something to the way the Aussies do things. Doesn't explain why the car went so lean from the tune right before the cam install.

[pdsq98gt]

Bad MAF?

[5_Liter_Eater]

Yea, disable the MAF and see if it trips the DTC in SD.

[2xLS1]

I think he's already tried another MAF. Problem is we're about 100 miles apart and we ran out of time the night it was getting tuned and he needed to get back home. I want to try some other things as I've never had any car do what his is doing before/after any cam install or tune and I've done a bunch. Like I said though, this is the first 04 GTO I've done with a cam. I've done another 04 GTO with a Procharger, but it still had a stock cam and no P0101 problem.

[2xLS1]

I'll add that it sets the code immediately at start up just idling and the scanner shows the MAF working, frequency going up with rpm increase and the dynamic airflow goes up with rpm increase. If you clear the code it sets again immediately.

[outsiders]

the more i look at my old stuff and the more i read, the more i think increasing the maximum delta airflow would bandaid the problem. i think cleaning up VE and then recalibrating the MAF should make things fall right in line.

[Street Legal]

I'm the tuner and in well over 100 cam tunes from mild to wild I have never had to change that table from stock. This is the 1st 04 GTO cam tune though, so maybe it has something to the way the Aussies do things. Doesn't explain why the car went so lean from the tune right before the cam install.

it depens on the car and how the pcm uses the values to set the code..some PCMs will set the code as soon as u go to WOT some of them wont.i tuned over 100 cars too and had some of them threw P0101 after a cam install i just increased the AIRFLOW DELTA and solved the issue no code and the car drives great.

[2xLS1]

FWIW, it was the delta air table, and the reason I've never had to increase it before on other vehicles is the 04 GTO table is populated with values about 1/4 of the values you see in a LS1 F-body or Gen 3 truck.

[outsiders]

here is some nice info

check this out.

stock 04 GTO maximum delta airflow table


04 GTO maximum delta airflow table x3


stock FCar maximum delta airflow table

[TDCRacing]

Thanks. This just helped me out