Hi there guys. I have a 2009 LNF sedan and I'm throwing these two codes. I know that both of these are lean codes. The car has been tuned with HPTuners for the last 25k miles pushing 21 PSI. The only mods to the car are a ZZP upper charge pipe and ZZP catless downpipe. There is no difference in drivability or anything of that nature. I have looked for boost/vacuum leaks and I have used a boost leak tester also - I can't find any. I'm just sick of looking at the check engine light and I want to make sure my car isn't running wrong. If anyone has had an issue similar to this or if anyone could be of any assistance, that would be great.

 

I am assuming you don't have HP cable or an interceptor scangauge?

I'm willing to take a wild guess and say your fuel trims are really out of whack.

I would not get into boost much until you figure out what's going on.

Chances are you're getting a bunch of KR also.

 

I do not have an interceptor or an HP Cable. I do have a wideband though. Should I take out the downstream O2 and hook up the wideband to it and check it through that or do I just bite the bullet and buy an interceptor?

 

Just bought an interceptor. Should be here next week sometime. Will post results soon.

 

That's good.

One thing I would do is clean your MAF sensor thoroughly. If it gets dirty I would imagine it senses less air coming in therefore the PCM is always adding fuel to compensate.

 

Wow I just discovered this awesome link in the stickies.

I did a quick glance at both your codes......

https://service.gm.com/gmspo/mode6/p...F%20Engine.pdf

 

So what are you saying exactly firehawk? I guess they are both rich codes based on that spreadsheet but what does this mean?

 

my guess is fuel trims out of wack. who tuned you?


Heres something to try, disconnect battery for 5 minutes, reconnect start car and begin driving. CELs should be gone but if you have a boost leak or vacuum leak, they would be back within that drive.

If they dont comeback for a very long time, lets say a week of driving then your tune needs some adjustments. Ive had a tune that took a drive from Baltimore to Miami to kick a CEL. Tuner made some adjustments and wahlah. No fuel trim drift.


If its a leak, you may not notice even if you are still hitting 21 psi. You can have a small leak and your turbo can work its ass off to compensate for it. the issue and where the CEL comes from is the measured X amount of air (MAF) going into the turbo does not equal the measured X amount of air (MAP1/2) entering the engine.

Areas to check for boost leaks or vacuum leaks.
- MAF sensor secured to intake
-Intake secured to turbo
-Charge pipe secured to turbo and intercooler (check the couplers to make sure there isnt a hole. tightening T-Clamps can cut a hole in them if to tight).
-rubber diaphragm inside the by-pass valve located on the turbo. (factory ones have torn in the past, not many cases.)
-Check intercooler for cracks in endtanks (factory intercooler known to crack here. made of plastic.)
-Vac lines disconnected at turbo, lower charge pipe, or anywhere in-between.


Good luck.


Edit: I see you have a ZZP upper charge pipe. Is this a recently added upgrade? Did your CELs appear after adding this? Wondering if indeed a clamp was too tight and cut the coupler. ZZP tells you to reuse the rubber couplers on the stock pipe. I can see those being cut. Maybe overtightened on the intercooler side cracking the intercooler. its possible.

 

The tune was on the car when I bought it and it was tuned by the previous owner. He was on this site, his name is padlock. The upper charge pipe has been on the car for a year or so and the check light just came on a month ago. I've tested for boost leaks and I couldn't find any. Would I be able to hear it pretty easily? Because when I'm driving, just cruising not boosting or anything, there is like a whine/whistle which could be a boost leak perhaps?

I can clear the code. The first time I did it, they went away for about 110 mile. All on the same ignition cycle (I didn't turn the car off in that time.) The next time I cleared it, they went away for about 60 miles and like 6 or 7 ignition cycles. Then the most recent time, they came back after about 60 miles also.

But I will have the interceptor in tomorrow so I'll be able to provide stft, ltft, afr, kr, etc.

What numbers should I be getting for those values?

stft:

 

KR should be 0 lol.

STFT and LTFT should be 0 as well but as its actively getting readings the LTFT should be +6 to -6 for comfort. STFT is going to go all over the place but should average near o. I believe you cant exceed +/- 18 on the LTFT or its tripping a code. +/-18 LTFT means your running 18% richer or leaner to get your AFR.

AFR should be 14.7 roughly under all conditions except some changes in acceleration, 100% acceleration, and certain deceleration events. The interceptor has something called command AFR (CMD AFR) Put that on the upper space and AFR on the lower space so you can actively compare command AFR vs AFR reading.

The guage is pretty neat. I think they could be brighter tho, blue seems dim... almost useless during a bright sunny day. great at night. You can view up to 8 parameters in a cycle of 2 at a time. I keep LTFT and STFT together, AFR and CMD AFR together, IAT and IAT2 together, and I thing I have Ambient and MAF together. Ambient is mainly for me to see IAT and IAT2 vs Ambient. MAF was to see how much air the k04 turbo flowed and I never changed it back to KR.

 

Well I just set up the gauge and I have some findings...

Knock read zero under all conditions - maybe a bad knock sensor?
AFR (not command AFR) - read around 13.5 at idle/cruise. Ran right around 11.0-11.2 at WOT. What is command AFR? Should I monitor that?
Fuel Trim B1-all over the place. 2.3-3.5 at idle/mild cruise. WOT it was at anywhere from 12-15.

So... I more than likely will need a tune? What do you think? Who do you recommend to do the tuning?

 

If your car was tuned prior and you made zero changes since then I would say something needs addressed on your car first.

**This is assuming after the initial tune the trims were dialed in good.


Knock sensor bad, I doubt it, there's two of them.


EDIT: I re-read your posts to refresh my memory. I would personally invest in a HP tuners cable and adjust things yourself after making damned sure everything else is ok. You don't want to tune around an issue.

One big plus to the HP cable is in the future should you get rid of your car you can re-sell the cable for damned close to what you invested in it.

 

Also, it's impossible to watch KR under all conditions and drive.

Set one of your alarms to blink the red lights anytime it sees KR. I set mine to alert on anything above 0.01

But KR isn't your issue, just a thing to set in the gauge.

If that starts flashing and you are under heavy load LIFT YOUR FOOT unless you want lighter pistons.

 

My tuner claims that everything was perfect on the tune and has not been adjusted for 25k miles. It just all of the sudden threw these two codes. My tuner seems to think a problem lies in a boost leak or a sensor rather than anything tune related. The car has a stock intake so its on stock MAF settings also. What should I look for? Where should I start?

 

I agree with your tuner.

Clean your MAF. Start with that.

You could just replace it if you want. Fortunately ours aren't super expensive like some are.

Assuming you have no air leaks then the MAF is by far the most likely culprit.

The sensors get dirt build up on them which would cause the car to not sense all the air going in which should result in positive LTFT as it would be constantly adding fuel to account for the air it didn't sense going in.

 

What are your LTFT's at? That shouldn't change much as you drive like the STFT do.

 

LTFT is around .6 or 1. If that was all it was is a dirty MAF I would be a happy man. I'll start with that then.

 

Hmmm, anytime the LTFT's are + or - 5 you're doing great.

That kind of rules out unmetered air.

Keep in mind though, everytime the codes are cleared those reset to 0

If you reset codes recently you need to drive around a bit to get the LTFT's to start settling in to whatever they are going to end up at.

Different rpm's, different loads to get them to learn up.

 

But isn't it a horrible sign that the STFT goes to like 15 on WOT?

 

Potentially, but you need to get an hptuners cable and log it, not just look at the interceptor as you floor it. I'm assuming when you go WOT you're above 3500rpms?

 

That is correct ECaulk I am above 3500 RPMs. I do not have access to an HPTuners cable at this point so I'm just trying to base it off what the interceptor reads.

 

The engine shows no knock whatsoever. The fuel trims are out of whack. Would a good step to be to clean the MAF? Would it really be possible that the upstream O2 (code P2195 is an upstream O2 code) would be throwing the AFR out of whack?

 

If your LTFT's are near zero then I doubt cleaning the MAF will do anything.

My STFT's will jump from 12+ to 12- at times but always average out to around zero overall when logging.

If your AFR's are out of whack the LTFT's will reflect this after a few miles of driving.......

But if the o2 isn't too expensive then IMO it's worth changing. They do not last forever.

 

Here's a thread with a TON of LTFT/STFT info's.

LNF STFT and LTFT Tuning - Page 8

 

One thought I just had.

Disconnect your EVAP hose and cap off the solenoid so it can't suck in air.

It's not really important to cap off the hose itself, just leave it disconnected.

Drive and watch your trims......see if it makes any difference.

In theory a failing EVAP solenoid could cause unmetered air to enter the engine but again I would think your LTFT's would reflect this.

Mine is capped off right now because I'm working on dialing in my trims to my maf/intake setup.