Cylinder 1 misfire and lots of knock

[Wired]

So I've been trying to figure out why my cylinder 1 is misfiring at WOT before bringing it in to the stealership AGAIN.

So I set up my log with the injector pulse rates to see if I could see something and went and did a few pulls. I got my misfire like most times so I went back to the logs and saw that in 1st gear at full throttle I was getting 7.5 degrees of knock and then it went down slightly to about 6* in second and third gear. I assume this is not normal for a GMS1 tune with nothing but an exhaust and powell oil separator.

Thing is, it doesn't do it all the time.

Could anyone look at the log (its very short) and be able to notice anything specifically wrong?

Here is the log: https://www.mediafire.com/?i4gw22vd0yvujtr

2010 LNF GMS1. 33k miles.

[MikeM173]

First off I'd like to say that the gm stock and stage tune are horrible and i have seen them cause knock. Not 7deg at WOT. Have you touched the tune at all? Try to give as much info as possible. Also might look at mechanical stuff to make sure the car is actually running properly. With that I would also say check your knock sensors to make sure they are clocked right.

[codename Bil Doe]

It would be your front knock sensor to check if it's kr on cyl 1, only. Pigtail should be pointing 9 o'clock.

If you have changed the tune what have you adjusted?

[Wired]

Haven't touched the tune at all, it is straight gms1. Before that the car was bought with a crappy tune with none of the supporting mods it was tuned for originally. I didn't even know for a couple months and then I figured out why my fuel trims were 14% off. Ended up needing a new turbo under warranty. I also cleaned the valves thinking the common LNF gunk problem might be causing it.

So:

Knock sensors are located in front of block and there are two? Also:

It may be the result of the misfire I can't figure out on cylinder 1 at WOT. I've swapped plugs and coils and now am left to injector or fuel pressure or valve train. Being only WOT makes me think injector.

What would be the best parameters to log to diagnose an injector?

[cobaltssoverbooster]

gm tune has a bunch of management active...this usually creates kr as it predicts events and removes timing from the main tables...in doing so it registers the removed values as kr. false kr. clocking the knock sensors has helped some but its not a guaranteed procedure for reducing knock control issues. gm tune is a good starting point but reality is everything needs tweaking.

injectors fail and cause massive misfires...result = code....other than that you get static misfires which are normally issues of e60 and higher. this is not an injector issue unless you are having popping noises by the intake under minor boost then you have injector seal failure.

[MikeM173]

Yes both knock sensors are on the front. The one on the passenger side is the one to look at. I would definitely consider it a tune issue except that amount of KR is higher then I've seen but I also haven't logged much of the GMS1 tune. I haven't looked at the log but my guess is that if it is for a short period it's most likely the tune. The GMS1 is a horrible tune in my eyes.

[cobaltssoverbooster]

yes its bad but in a full stock class with no tuning allowed the gm kit is an allowed modification because it is dealer issued and installed with warranty backup so it has its time and place.
if your not needing to meet class restriction then yes more power can be made on a stock file modified for sensor upgrades, been recorded numerous times over and over.

[Wired]

gm tune has a bunch of management active...this usually creates kr as it predicts events and removes timing from the main tables...in doing so it registers the removed values as kr. false kr. clocking the knock sensors has helped some but its not a guaranteed procedure for reducing knock control issues. gm tune is a good starting point but reality is everything needs tweaking.

injectors fail and cause massive misfires...result = code....other than that you get static misfires which are normally issues of e60 and higher. this is not an injector issue unless you are having popping noises by the intake under minor boost then you have injector seal failure.

I do have a code for cylinder 1 misfire (forgot to say that) and it was the result of many WOT pulls resulting in the flashing engine light and a pending code for cylinder 1. I do hear a sort of popping sound but I was thinking it was the sound of the misfire itself through the exhaust.

I also plan on a conservative tune for some bolt ons around the 300/350 zone once my power train warranty is up.

[codename Bil Doe]

As CSSOB said, the ECU uses KR as a catchall for any timing being pulled. But, if it was ECU pulling timing for any reason it wouldn't only be on cyl 1 and wouldn't be causing misfires and codes. I think that can be ruled out.

[cobaltssoverbooster]

the lnf chews plugs up like crazy...when i tracked mine i had about 6 sets of plugs laying around. have you pulled any to check them out? i didn't see anything posted unless i missed that little note.

[Wired]

I have swapped the plug between 1 and 4 as well as the coils. The problem persists on cyl 1. I have not changed them out with a new set.

[cobaltssoverbooster]

what was the color of the deepest part of the insulator?
any spotting?

[T-Man]

Wonder if there's a ringland issue on #1

[Wired]

The previous owner appeared to be an idiot with the car so anything is possible. I keep finding issue after issue and most were preventable and/or operator created.

I will pull the plugs tomorrow morning and get a picture. All the plugs looked the same (looked good) and were gapped correctly. My dad and myself have a lot of experience with engines (older non computer stuff like our GTO) and this is stumping me.

[codename Bil Doe]

Sounds familiar. Seems to be the theme with used cars. I fixed 99% of my racecar. Just found out about the last 1% on track. Always start with the easiest stuff to check first. Because it's one cylinder, only, it should be quicker to narrow down.

[cobaltssoverbooster]

normally ring lands dropping in the lnf causes oil to coat the spark plug. now im saying that from the 10 i have diagnosed so far, but anything is possible especially if the ring land is just cracked and not discharged yet.

[Wired]

Pulled the plugs today. They are gapped right at .033 (wont fit through the .034 but fit with room with the .032). All of them look the same. I also used my borescope to see if I could see anything odd in the cylinder but I wasn't able to get a good enough angle. Nothing looked too odd though.



And 1 by itself in better light:



As far as ring lands. Wouldn't I be seeing either burning oil in the exhuast or contaminated oil? I haven't seen any smoke but I have NOT checked oil lately. It is about time to change it too.

[cobaltssoverbooster]

Ring lands are fine at the moment.
I wouldn't worry about them just the plugs and the tune.

[Wired]

Well I took all the plugs and moved them over a cylinder. The plug on cyl 1 was not very tight when I pulled it. Drove it 40mi to work and back yesterday with a few pulls and had no problems.

[cobaltssoverbooster]

the lnf is very sensitive torque wrench required....18ftlbs max all aluminum heads