So after a long, I mean long, while, I finally installed the 3inch MAF, but to my suprise, its extremely lean! At first start up, the car idled great and then all of a sudden, the idle started dropping and i looked over to my LM1, and it read it was reading around 20-25!!??

I immediately turned the car off and added corrections to the VAFC, just for safe keeping. As I started up the car again and turned on the LM1, it was now at around 18.5..... so with the car running, I added corrections again, this time I maxed it out to +50... a little crazy I now, but now it was at 16.3. I cant seem to get the a/f ratio below 15 at idle with the 3 inch MAF. Is this normal!?

I'm currently tuning on top of a T/S ECU. I havent driven it yet since it got kinda dark and I had to get my daughter ready for school. Here's a log I recorded just to show A/F ratio starting from idle to 4850rpms.

Here's the link: https://share.acrobat.com/adc/adc.do?app=share


There are no vacuum leaks that i found, but I did hear a more noticable suction noise coming from the intake/throttle body. It was late and dark so I really couldnt search for any leaks, but i'm almost certain there's no vacuum leaks.

Have any of you that have done the 3 inch MAF encountered the same issue regarding a lean idle!? Is this normal!?!? The car's idle is fine with the +50 correction i've done to it..hehehe, i'm just not too comfortable with that.

Thanks in advance!!!

BTW, I meant it to put ridiculuosly lean, not rich!

 

Just turn your base fp up and zero out the correction on the VAFC.

 

What's it at in closed loop?

 

The lowest I saw it at closed loop was around 15.8. Its seems though it takes a while for it to settle down to 15.8... it would start at around 20._ and then slowly drop down. Every time I would push on the throttle, the a/f ratio would sit at around 17._.

This has only been under one observation but I just wanted to see what everyone had on thier first initial install of the 3inch MAF.

I will try to increase FP to see if that might help the idle's a/f settle down a bit.

Any other suggestions!?

 

FYI, when I first tried it, I need to add +27% to be where it was before (13 - 14). It's unfortunate the VAFC doesn't have the IN/OUT capability of the SAFCII.

 

Hey NewMex. I was reading all the relevant threads on installing a biger MAF tube on a 5.5 gen. I noticed when you ran the 82MM, you had the SAFC II setting at in 1 out 17. I am going to have TS reflash my ECU next Monday and I am going to install the 76MM MAF tube prior to the reflash. After that, I am going to fine tune with SAFC II. What setting should I keep it at?

 

What do you mean!? Doesnt the VAFCII have the same capabilities and then some as the SAFCII!?!?


I'm meant to say Im using the VAFCII.... what settings should I have it set at!? I currently have it at 1in 1out.

 

the safc and vafc are aittle different .. read some of the old thread and it will explain alot .. long story short sell the vafc and get a safc or e-blue and you should be ok

btw what is your base fuel psi set

 

The fact that you're so surprised that the engine would run lean after installing a larger-bore MAF is scary, honestly.


And title fixed.

 

lmao.. yeah if youre runnin this on a 4th gen.. i have mine set at +14% at idle with a 2 in 4 out hotwire setting.. but i dont think a VAFCII will do that..

 

I'm not surprised its lean... just didn't think it would be so lean the way it was. This is the first time I attempt to tune any vehicle myself, so I wasn't sure.... everyone starts off somewhere....and I'm not as fortunate to have other maxima drivers in my area that I can go to for advice, so I come here.
I've done some research but I can only do so much without asking questions... I don't live on the forums so the little time I spend on here, I read and ask questions.
Thanks for the advice as well as the sarcasm.

Anyways, I have had a little bit of time to mess around with the VAFC and making corrections and I've managed to get it to run around 13-14s under regular driving conditions. I have yet to mess with wide throttle adjustments because I didn't want to mess it up.
Bare with me guys, and yes it might be a bad idea for me to do it myself but i'd rather learn.

 

it says in the manual you can change the sensor type.. i dont know if it does the same thing my safc II will do.. but its worth a try.. cause if you dont correct this to where the computer keeps trying to adjust it at idle itll end up throwing a lo/hi egr flow code..

 

I would see how it runs with the 76mm & the same IN/OUT settings (same for both 1/1, or what not). But I too have a 76mm MAF and she ran as lean as she did with the 82mm. I'd say that you would still want to stay w/ the 1/17 settings, but try it out just so you could see, as I'm assuming you have a wideband.

From my experience, I have never seen an IN/OUT on the VAFCII to suggest it has the same capability as the SAFCII in that aspect. Different members have tried different settings and have yet to determine one that works like the SAFCII 1/17.


FYI, I was in the 18-19AFR realm before adding fuel or changing IN/OUT settings.

 

as was i.. but correct me if im wrong.. he has a 4th gen.. 17 out is not the needed number.. its 4 out

 

That's correct, but for the OP w/ the VAFC... the SAFC settings don't apply.

 

Good to see you back around the all motor forum!

The lean issue is pretty well documented, it shouldn't have been much of a suprise.

So you added +50% correction initially, and it still ran very lean, but you "messed with it more" and got it to run where it should. Maybe your settings were just wrong at first?

The tuning at WOT will be pretty easy... just start with high correction (since you know it'll be lean) and let it run rich initially, then lower corrections to get where you need to be. Optimally you'll want to increase fuel pressure or injector size to get the extra fuel you need, as adding fuel on the AFC will indirectly retard timing a little.

 

it does, I am currently using in 4 and 4 out

 

So:

4IN/4OUT on the VAFC II, w/ 3" or greater MAF ID, and no corrections are necessary in order to run just like it did prior to large MAF ID install?

I would imagine you would need a different IN/OUT combo in order to compensate for the added ID of the MAF.

 

nmexmax is right on this one.. it specifically states in the manual that having the same in/out number wont change anything.. only when you use a combination of numbers will it convert/change signal through the controller