09 LNF with Nothing but Knock Problems

[SlobaltSS]

I have a 09 SS running the following:
Injen upper
Hahn Intercooler
ZZP lower with MAF relocate
Stock k04
Hahn Coolram CAI

I have insane knock issues with the car and they make no sense to me anymore. I have been all over the car, wrapped pipes, torque everything, etc. I get these random knock fits that appear false 95% of the time. Last week the car was fine. I was having <3 degree knock spike on tip in only on number 4 right around 2800rpm. Everything else was zero. I had just clocked the knock sensors like I read on here. I parked the car and changed all of the brake parts. Did nothing else and everything is good and tight. I go to drive the car and I now have up to 12 degrees of knock on 1-2 and 8-10 on 3-4. I did a rewrite of the tune and it all went away. Now it is slowly coming back. It was 0 for a while, then 3-4, then 6's, and then back to 10's. WTF?!. How can it just come and go as it pleases?

This issue has been going on for a while now and I am getting pretty fed up with this car. In my quest to fix it I have replaced the following:
Both t-maps
Soldiered both t-map clips
The MAF twice with OEM new
Spark plugs twice now gapped at .032" once and .028" the second time. AC Delco stock.
Adjusted my wastegate rod
EVAP solenoids
Vacuum tank delete (mostly to get to the knock sensors)

What else code be causing the PCM to seem like it is learning to knock so randomly? Nothing is hitting anything anywhere.

Also, I have a very well verse and knowledgeable tuner so that is not the issue. I am using tunes that have been proven time and time again for years. I am not making any adjustments myself.

+++++++++++++++++++
Questions:

Does the factory wideband control anything in the PCM, or does it just display data? Could it be bad and causing running issues?

Is it normal for VE airflow to lag 5-8lbs/min behind MAF airflow on a MAF relocate set up?

Should MAP (kPa), Boost Sens (kPa) and Boost Des (kPa) all be about the same under WOT?
ex: under 100% pedal I have 255kpa MAP, 207.2kpa Boost Sens & 254kpa Boost Des with no knock.

Why does HPT show all of this knock, but my RPD never sees any?

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Sorry for the long post; I am trying to be as informative as possible. Also, my tuner is remote. I am mostly asking to see what I could be missing in tracking down my issues. This all started when I went to a MAF relocate after changing the clutch. Prior to that the car had 0.0Kr across the board at all times. Putting the MAF back into the intake does not change anything either, I tried that too.

[cobaltssoverbooster]

post a log and tune the lnf gets tons of kr when the data isn't smooth enough.

[SlobaltSS]

Two logs are attached. Both are on the same tune. Nothing was changed on the car between these logs except for my brakes lol.

[MikeM173]

Yes the factory wide-band controls a lot and is part of the entire tune process and if it's acting up you should see knock issues along with fueling issues etc.

VE and MAF is a finely tuned car for them to be equal but in my opinion it's not a finely tuned monster. Them not matching is not causing your knock issue.

Forget about the boost sensor. The boost lo res is the most accurate for reading your boost pressure. Boost des is what your asking the car to do. It'll read what you have set for parameters and lo res is what is actually at.

Your RPD is measuring total knock which doesn't display each cylinder. That's why I recommend running HpT.

The LNFs are very finicky by design. I've had people beg me to get it to zero KR when remote tuning and while it's possible it's at some sacrifice somewhere usually. People tend to think they have everything set up correctly or that they understand things and they want it changed a specific way. Your best bet is to just listen to your tuner if he is reputable like you say. If he is not a reputable LNF tuner I would find someone else but if he is take his advice. Nothing a tuner hates more then someone trying to throw knowledge at what he already knows but at the same time you need to have some knowledge to give him so he can figure it out. It's a fine line to walk when remote tuning. Not saying he would just give up but it makes things difficult when the person being tuned thinks they know more then they do or they ask for unrealistic stuff (not saying you are).

Everything on the LNF is finicky and it all ties together. This is why not everyone can properly tune one. I wish you good luck. I don't read tunes or logs anymore except for customers but if you ever want to PM me with specific questions I will text you my phone number. My number one goal is people having a properly running car and them being happy. Not to make money.

[SlobaltSS]

I completely trust my tuner and I know that he knows what he is doing. He is also very busy and helping me out so I choose not to bother him; which brought me here. I am trying to make sure that I am not overlooking mechanical stuff that could be causing my issues. Like how my car runs perfectly fine with no knock one day, then decides the next day it will have 12 degrees when no changes were made to the car. How can it run fine and then not on the same, good tune? I do not feel my issues are coming from my tune and I am looking for advice/what to look at on my end to make my car work. It is baffling to me that it can be fine one day, running 12Kr the next, and then fine later in the day. Also, it seems that post flash everything is good and that the car LEARNS to knock over time. I came to work with up to 12Kr when 3 days ago I had 0. I am going to reflash the tune and can almost guarantee that it will be back to zero like it usually does.

I am currently running no EVAP since it was causing insane amounts of Kr. I have no replaced the o2 and it can take up to 3 minutes to heat up and work? I am assuming it is maybe going bad? That seems like a long time...

My RPD never shows any knock even when HPT shows 12Kr total. I have never seen the RPD show anything except 0 on Kr even when the car is retarding and the gauge shows it.

I definitely know that I do not know nearly enough about these cars. I am trying to learn more about them everywhere I can so I am not constantly chewing at my tuner's ear for hours on end lol.

[SlobaltSS]

Also, is Lo Res (kPa) the Map or the Boost Sens reading?

[MikeM173]

Lo res is the charge pipe map sensor.

It's a good thing you have a reputable tuner as a lot of people a lot of the time don't. If you haven't tried a new wide-band o2 then go for it just make sure you get the right one. Some aren't as great.

It very well could be something mechanical or wiring that is partially broke somewhere. I've seen a lot of issues come down to wiring. Whoever reads the log on here or your tuner should look for something out of the ordinary in the log to help narrow down where the problem might be.

[SlobaltSS]

I will replace the o2 sensor and see if that changes it. I just grabbed a closeout OEM one from Rock Auto for $50 shipped.

My next step is my last step I suppose. going to grab a 9v battery and wiring diagram and put power to the PCM side and a multimeter on the other of every harness that has to do with engine control. FML this will take forverrrrrr lol.

There are lots of things out of the ordinary. I never should have bought this POS car lol. Live and learn I guess; last time I buy an already modded car from CL.....

Thank you for the explanations; I appreciate it.

[codename Bil Doe]

Modded cars are danger city. Just ask me how much stuff I've had to undo and fix on my racecar.

iirc, 12KR can be a result of bad knock sensor. It's been awhile for me, but reread the kr sensor clocking thread. I seem to remember that clocking it incorrectly can generate 9°+ of false kr. Unplugging it should make the ecu automatically read 12° of kr.

"KR" is a catchall safety for this ecu. If it wants to slow down the ac or the turn signals are flashing too bright it'll add KR. Because yours is creeping back up to that 12 window, I would check the wiring on them. Maybe internally fractured wire or bad sensor. Probe them both.

This is where Mike disagrees with me by agreeing with me.

[SlobaltSS]

Thanks. I had a suspicion that the PCM uses Kr for more than just knock. The front sensor spike kr first and the rear one follows only after the front has passes about 6 degrees. I will replace the front one since I only have one brand new one right now and see if this changes anything.

Should I reset the PCM when I replace it? Resetting it has historically made my issues go away and then slowly come back.

[MikeM173]

Bill I have to definitely disagree with you. Everything you said is a possibility.

[MikeM173]

Keep in mind every time you flash the car needs to go through a learn phase. I would reflash especially because that is what you have been doing for a while and you don't want to change everything. Change the sensor, reflash and see if it does the same thing you've been seeing.

[SlobaltSS]

10-4.


Also, how long does the car take to pass the Oxygen Sensor Heating test under the DTC tab? Mine never completes the test, even after several hundred miles with no reflash.

[08VRSS]

If it wants to slow down the ac or the turn signals are flashing too bright it'll add KR.

Funniest thing I've ever read on this forum lmao. ;P

[MikeM173]

SlobaltSS, as much as I'm sure you do not want to send a file out, I bet I can possibly locate your issue if I see the tune and the log. I don't get on here much with my computer to help out anymore, but if you want to PM me and we can talk. If you don't want to send it I completely understand. Just figured I would try to help out a little better then this guessing game.

[MikeM173]

08VRSS, I can't speak anything on turn signals, but I do know that Bill had some issues with some stuff and upon messing around with his AC he noticed a difference in KR etc, from what I can remember. I know this ECU shows KR when there is none and it does use it for a lot of control purposes. As for what Bill mentioned we would need his exact input because I have not personally had those issues.

[codename Bil Doe]

Flashers and ac were a joke. The kr due to unrelated issues and the 12° from improper clocking and unplugging one wasn't. This ecu uses kr as a catchall for everything when it wants to reduce power.

A good example is logging a tuned car while you're driving around. KR will mirror throttle movement a dead stop or cruising while below 180° ect. As soon as my 09 hits 180° it'll instantly disappear. Before that it will mirror the pedal input from 0-4°.

SlobaltSS - that's really a deal you shouldn't pass up. Mike knows what he's talking about. Having him look over your tune could really help. May want to email it to him.

As for reflash I 100% agree from experience. These ecu's will learn bad habits while compensating for sensors and/or parts that fail. Those bad habits can't be unlearned through any access we have except by a reflash

[cobaltssoverbooster]

the clocking kinda helps. i passed the clocking corrections i performed off as "of no benefit," but some say its better afterwards. im guessing the clocking is more of a contact change on the block helping to clear a signal up on a sensor that may have been factory under torque and vibrating between the block and its fastener some.

i cant speak for the knock sensor learn time but if you make a change and do 5 pulls on the dyno the last 3 will be closer together than the first 3 due to learning.
o2 sensor learn is key cycle and run-time based. iirc the gm tech manual says it must see at least two key cycles with a minimum drive time requirement per key cycle. on top of the on time requirement you must meet engine operating temp for a delayed amount of time and the trims must be within a preset range (under +/- 9%). Its a very picky test and can trigger quick or slow its just luck of the draw. only the gm tech2 can force a test iirc.

[MikeM173]

Bill you really have to stop leaving me in positions to apologize haha. I thought you had an issue with A/C a while back but I stand corrected. I haven't seen much change with knock sensors either but then again I've never personally tested it out.

[SlobaltSS]

So last night I added 2mm to my wastegate rod, replaced the 3-4 knock sensor, replaced the plugs (OEM gapped .030"), and rearranged coil packs (just because). I drove the car last night and it was mostly fine. Had no knock at all for a while, then would get random spikes in the higher load, lower RPM range of less than 2 degree. It was also only on the 1-2 sensor. After about 20 minutes I was like cool; something I did worked. I figured I would order another sensor and replace the 1-2 one and finally be done with this. Wong. This morning, car is just as bad as it was before. Up to 12 degrees all over, failing the MAF, knocking when I free rev the car, everywhere.

My Oxygen Sensor passes, but the Oxygen Sensor Heater never does.

I am leaning to maybe the PCM is bad? I have a spare coming my way to test that theory.

I am really beginning to wish I kept my LSJ and just went turbo on it.