New MAF Sensor

[05LegacyGTGa]

I think I'm just going to replace the MAF sensor on my car to see if it fixes the terrible LV numbers I'm getting using the BtSsm App. Should I just go with a Denso one or are any of the other brands any good (like Walker etc from RockAuto or something off eBay)?

[relative4]

If you're just going to fire the parts cannon, get a Denso; anything else will cause problems.

If you want to diagnose your problem, start by posting the LV here.

Also all mods and current tune.

[05LegacyGTGa]

It's completely stock. I'll get the LV off and put them up!

[05LegacyGTGa]

Here's a few:

BtSsm_LV_20180318_1229 by kornfan891, on Flickr

 

BtSsm_LV_20180309_1909 by kornfan891, on Flickr

 

BtSsm_LV_20180302_2148 by kornfan891, on Flickr

 

BtSsm_LV_20180302_1935 by kornfan891, on Flickr

 

BtSsm_LV_20180221_1416 by kornfan891, on Flickr

[Perscitus]

A bit all over the place. That Mar-2nd LV looks fairly bad.

Assuming that was before the MAF swap.

 

Mar-19th looks better, but can be further improved.

AF Learn A isnt ideal but nothing much to worry about.

 

And the -2.8 deg FLKC learned somewhere between 1.65-2.6K RPM

and 0 to 0.85g/rev is also irrelevant, out of boost, potentially false knock.

 

See if IAM stays at 1 and if you can get the Timing correction matrix to fill in more

with some drives that put you above 1, 2g/rev and across 1-5K RPM.

 

If the Fuel and Timing learned values keep fluctuating, something else is still not right.

[relative4]

Who told you those numbers are terrible? For a stock tune, they're gRRREAT!

Two recommendations:

1. Smoke test. You may have a very small vacuum leak. You can buy a paint can smoke machine for $80 from eBay, make your own, or borrow one.

2. Buy a Cobb AccessPort and flash the Stage 1 tune. In addition to improving performance substantially, it will help extend engine life by reducing the likelihood of burnt exhaust valves.

 

Edit: I was really just looking at the 2 most recent snapshots, under the assumption that you fixed whatever was causing all the earlier fluctuations. If that's not the case, and you're still fluctuating, I would start by checking the grounds, and then follow the recommendations of Perscitus, who is far more knowledgable than I.

[05LegacyGTGa]

I haven't touched it other than for the 3/18 one it has new plugs in it. Thought I might start with the MAF. I'll do some logs tomorrow and post them up.

[relative4]

Then yeah, check the grounds, and include roughness counts in the logs.

 

What plugs did you use?

[05LegacyGTGa]

I used the NGK 7913 SILFR6A

[relative4]

I used the NGK 7913 SILFR6A

 

Excelente

[05LegacyGTGa]

What's the best way to attach a log file (Excel)?

[05LegacyGTGa]

Nevermind. I think I figured it out.

BtSsm_20180322_134232_knock.csv

BtSsm_20180322_135358.csv

[05LegacyGTGa]

Anybody? I go cross-eyed looking at it ha

[relative4]

Personally, I've never looked at logs from an auto before, so I can't say much helpful. The boost targets seem low, and the wastegate duty cycle looks weird to me, but auto, so I dunno. However, I definitely stand by what I first said - smoke test.

 

Looking at the log with the knock, looks like things go a little haywire when you shift.

1->2: You go crazy lean, RPMs drop all the way down under 1000 - is that normal?

2->3: Crazy lean again, RPMs only to 1600 this time, knocks occur presumably because of the lean mixture.

 

I think the extra-high vacuum happening during the shifts may be sucking open a minor vacuum leak that doesn't have much effect under other conditions.

 

I have no idea if the way it's shifting is normal.

[05LegacyGTGa]

I've been told before that the auto will show a decent amount of false knocks.