P0171 - again and getting more frequent

[Spamby]

Some of you may know that I have had some vacuum/boost leak issues the last month and half.
Few days after the initial work in July, I threw the P0171 code. Figured it was fluke and erased and relearned.
Code is thrown on the highway, nearly the same spot and at the same times. Always cruising around 70-75 and light throttle, light load and rpm's at about 3k. This code never comes up any other time or driving conditions.
A week ago, I got the code again on Monday. Erased and relearned
Last week, i got the code on Thursday. Erased and relearned.
Last week on Friday, code again. Erased and relearned.
Saturday. Installed new turbo inlet pipe and reexamined all of the lines and hardware. replaced gaskets and made sure all connections were good, thrice. I am pretty damn positive there are no vacuum or boost leaks.
Car ran noticeably better and thought issue had been resolved.
Threw the code this morning.
Erased this evening and did a two logs.
Fuel pump is at 66 or 100%?? Is this right?
Hopefully I got what is needed, so take a look and let me know what you think? Look at my journal for build specifics.

https://docs.google.com/spreadsheet/ccc?key=0AsnawVcut-qCdGsxQUM5RkxyTkhhQ2lxWE5qcHBjR1E#gid=0

https://docs.google.com/spreadsheet/ccc?key=0AsnawVcut-qCdDNTV0RzbmtKVGlyQjdlSGh1WXBpUkE#gid=0

 

[Spamby]

So since I'm learning tuning and how to read and interpret logs, I have noticed something screwy with my logs... or I may be screwy. Lol

As the AFR is richened, after stoich, the upstream A/F sensors voltage drops to negative. As the AFR's lean out, the sensor voltage increases. This seems contrary to what I know or think I know, at this point.
Should the sensor voltage drop as the AFR becomes lean and not rich?
If this is the case, this may be the cause of the code being thrown? The upstream sensor is not reading correctly?

 

[HolyCrapItsFast]

So since I'm learning tuning and how to read and interpret logs, I have noticed something screwy with my logs... or I may be screwy. Lol

As the AFR is richened, after stoich, the upstream A/F sensors voltage drops to negative. As the AFR's lean out, the sensor voltage increases. This seems contrary to what I know or think I know, at this point.
Should the sensor voltage drop as the AFR becomes lean and not rich?
If this is the case, this may be the cause of the code being thrown? The upstream sensor is not reading correctly?

I'm not 100% sure but the log is telling me there is still a leak somewhere. The reason I am not 100% sure is because it is not consistent. Look at the A/F Correction column in the second log and note the high trims. It is like it is intermittent, like when it hits a certain vacuum or pressure and it goes lean and trims go high. The fuel pump and O2 sensor appear to be working as expected. The O2 raw reading is in current, not voltage and it should go negative when rich and positive when lean. 0 ma is stoich (14.7)

 

[Spamby]

I'm not 100% sure but the log is telling me there is still a leak somewhere. The reason I am not 100% sure is because it is not consistent. Look at the A/F Correction column in the second log and note the high trims. It is like it is intermittent, like when it hits a certain vacuum or pressure and it goes lean and trims go high. The fuel pump and O2 sensor appear to be working as expected. The O2 raw reading is in current, not voltage and it should go negative when rich and positive when lean. 0 ma is stoich (14.7)

Hmmm. Thanks for clarifying the sensor part.

Well, I'm going to look hard at the CAI this weekend and see if something is screwed with it, post MAF.
I am pretty damn positive no leaks are present as everything has been replaced or inspected and clamped down. However, I'm not infallible. I will do another leak test and try a cigar smoke test.
There may be something I missed or created.

I'm visualizing flying through the engine and all if the plumbing. I'm weird

 

[fuji_production]

cigar smoke test wont help at all. I would get a boost leak tester and go from there. I would take every single evap and vac line off, inspect for cracks, and move on. On every subie i have worked on I have chased down boost leaks. It is like its inevitable. zip tie all your lines down real good as well.

 

[fuji_production]

have you seen this yet? http://forums.nasioc.com/forums/showthread.php?t=475620

 

[Spamby]

cigar smoke test wont help at all. I would get a boost leak tester and go from there. I would take every single evap and vac line off, inspect for cracks, and move on. On every subie i have worked on I have chased down boost leaks. It is like its inevitable. zip tie all your lines down real good as well.

Will definitely revisit all if the lines again.
Got a boost leak tester and plan to do another test.
Definitely have zip ties and am going to use every last m'fer.
Major pre and post hoses have been replaced along with gaskets. Has to be something smaller.

 

[Spamby]

have you seen this yet? http://forums.nasioc.com/forums/showthread.php?t=475620

You bet I've seen this. Have read it multiple times and will use it as a guideline.

 

[Spamby]

Check this log out. Markedly different with nothing done... i.e. no fixes or fiddling.

https://docs.google.com/spreadsheet/ccc?key=0AsnawVcut-qCdGxLeV9sTEJmUU4xMEQycW9xM3NaT1E#gid=0

 

[Spamby]

Informative.

http://m.youtube.com/watch?v=QwGICKqWgM4&desktop_uri=/watch?v=QwGICKqWgM4

 

[IGOTASTi]

So what all have you done since the code came on?

 

[Spamby]

So what all have you done since the code came on?

The short of it, lotsa things.
I'll post a history later when I get a chance.

 

[Spamby]

Summary is that I spent the day leak testing, soapy water, carb cleaner while engine running and watching afr. No leaks found. Put a wrench or screwdriver on every connection. Applied zip ties to everything I could or hadn't before. Cleaned maf.
Did some logs and basically watched the ltft go way positive. I didn't reset the ECU as I want to watch the progress.
No CEL so I'm hopeful it won't return. If it does, it will be in the next day or so as this seems to be the trend.

 

[IGOTASTi]

What do you think was causing it?

 

[Spamby]

What do you think was causing it?

I dunno at this point if anything was actually fixed. I'll see if I throw the code again.

On the Cobb bpv, there is a flange cover with 4 small screws holding it on. I noticed those were backing out again. This cover is what you take off to make it a hybrid VTA.
The Perrin CAI has too many couplers for my liking and no beading on the ends of the piping. Any one if these could have been letting air in, after maf. I'm just not real happy with it and may change to something else in the future.

I'm still not happy with the ltft as they are hitting high, but I am also watching it and seeing if after a few days of hot/cold cycles she starts to come back in line.

I wouldn't say fixed until I don't see the cel again after this week.

 

[Spamby]

F*ck the world. It's back on.

 

[IGOTASTi]

F*ck the world. It's back on.

Wonder if a sensor is bad.

 

[Spamby]

Wonder if a sensor is bad.

That's where I'm headed now.

I know Holy said the front sensor appears to be working normally but I can't help to think that it may be dying or the maf is fudged up.

Funny thing is that this all happened in July AFTER fixing the boost leaks.

This is a light load scenario, cruising on the highway and it always happens in the exact same location at the exact same times in the morning. Leaving the hot city and entering the cooler burbs in the morning during my commute.

If the maf or front AFR sensor is a bit wonky, would it freak out when suddenly temps drop several degrees and the air is more dense? Like seeing a 10 degree drop almost instantly.

 

[IGOTASTi]

I'm thinking bad maf, but we need Holy to help us.

 

[Batmobile_Engage]

Forgive me for forgetting, when was the last time your MAF was cleaned?