Hi All,

Something we are often asked about is replotting the MAF Flow table {B0802}, it's really easy to do because the scantool can do it all for you :)

You need to log the following PID's.
Engine RPM - SAE.RPM
Airflow Rate from Air Mass sensor - SAE.MAF (in g/sec)
Main Injection Fuel Flow Rate 2 - GM.FUELQ_MAIN_DMA

The reason you need to log the GM.FUELQ_MAIN_DMA PID is because the normal GM PID gets capped at 79.8mm3 by the ECM.
Click Here (http://efidownload.iqd.co.nz/software/GMPX/Actual_MAF.zip)and unzip the file 'Actual_MAF.map' into the folder -
\My Documents\EFILive\V7\Maps
(Note: this will not work on early LB7 O.S's, a new table will need to be made with the correct axis sizes).

O.K, so once you log those you need to go into the scantool and go to the Maps tab, load up the 'Actual_MAF.map' as one of your maps (A-J).
Click on the icon showing the 'X' and you should see the new MAF flow values in the Map table.
You can now just cut/paste them into table B0802, do some blending or smoothing and there's your new MAF flow table :) . No more MAF codes and you didn't even have to turn the DTC off to do it!

Cheers,
Ross

Good info!!

cool thanks for the info Ross

Neat.

pssssssssst diesel pilot-----reckon we need to try this??

NO KIDDING!

Thanks Ross

Craig

What exatly does the MAF do on our trucks?? Is this better then just killing the checks on the MAF?

What exatly does the MAF do on our trucks?? Is this better then just killing the checks on the MAF?


The MAF is linked to fuel delivery in a few tables.

Ross,

I do not see the correction for IAT, ECT and Baro...this could easily make a 10% difference. Is it possible to correct the actual air flow with the correction factors in the ECM? Not so much concerned about Baro and ECT but I see my IAT vary more than 30°C in log files.

Thanks

You are correct, they are not factored into the map I showed above, however, using that method I described is going to get it close enough the problem will go away.
All you need to do is do the actual logging then paste the new values in and look at the difference.
Or, I guess for the purposes of plotting a new map you could change all the multipliers to 1.00.

Cheers,
Ross

I tried the copy and paste but for some reason it would not let me....I'll find a way around that.
Even though I have the stock intake with stock filter the differences are quite significant.

GM did allow a reasonably large error range {C0904}.

Cheers,
Ross

So do we have both MAF and MAP sensors on our trucks?

Yes....the MAP is the the boooooost sensor.

Thanks Ross Helpfull Info

when we do the log for this is it best to have a real long log at different speeds or a wot run i just did this today and just noticed i only came up with a couple # compared to the example picture i thought maybee i need ed to log for longer:)

is this mostly used for the guys with twin and bigger turbos? i did notice after smoothing in the new numbers my table was higher values i have not loaded in this yet probbally tommorow

If you log for longer then the acutal values recorded will average out and therefore giving you greater accuracy.

Cheers,
Ross

If you log for longer then the acutal values recorded will average out and therefore giving you greater accuracy.

Cheers,
Ross

thanks