Setting the frequency to 0 effectively disables the MAF and should put you in SD mode (SES lights and all, unless you disabled them too).

You would only leave the fail frequency at 0 if you intended to run an SD tune and not turn the MAF back on and calibrate it for the new SD/VE tune.

Cheers,
Rob (Bad30th)

 

Setting the high fail frequency = 0 will fail the MAF when it reports any frequency greater than 0. Setting the high fail limit to 1 means the PCM will fall into SD mode the first time the high fail frequency is exceeded.

 

I read thru the thread quickly but here's what I see as your issue. (I didn't see anyone else specifically address your problem.)
MAF Fail = 0 is SD. SD uses the secondary VE table. You need to copy the appropriate rows from your modified primary table to the secondary table to see any effect. Do that and you should see better fuel trims. Now log, change primary and secondary tables again, log more... repeat until you're satisfied or bored.
Then reset MAF Fail Freq to re-enable MAF and go thru the MAF tuning procedure until you like the fuel trims again.

 

Ok. Say I set my MAF fail frequency back to 0 to enable the MAF.

Now when does the VCM use the Main VE table and When does it use the Secondary?

 

Scooter just explained that in the post 23

 

I guess what I should have said is:

Does the car ONLY use the the secondary during SD? Also does the car ONLY run in SD when the MAF fails? So in other words if the MAF is functioning correctly it will never go into SD mode?

 

i don't wanna be an ***, but you're asking very fundamental questions that have been answered to death here. if you read the stickies and search around, you will find a TON of material.

 

To answer your questions and hopefully put this thread to bed...

Yes
Yes
Yes

 

More info:

https://ls1tech.com/forums/pcm-diagnostics-tuning/363392-how-maf-really-works.html