o2 respond graph. which one looks right to you?

[???]

08 c6. mostly stock just bank 1 is really fast switching like. jagged looking bank 2 is smooth but seems slow
these are fairly new denso o2's if I remember right.

any thoughts? 2nd from the bottom purple is bank 1 light blue bank 2

[edcmat-l1]

Bank 1 has a miss.

[???]

thank you. I'll try a new one

I believe that's the easy one to change. 2 is buried and gotta remove the exhaust.


edit, or do you mean a missfire? it feels smooth?

[edcmat-l1]

thank you. I'll try a new one

I believe that's the easy one to change. 2 is buried and gotta remove the exhaust.


edit, or do you mean a missfire? it feels smooth?

Try a new one what? There's nothing wrong with the sensor. That cylinder bank has a miss. Need to diagnose and fix the miss.

[???]

yeah, I missed what your meant at first, I never considered it might be missing till after your said it.

so I'm not used to searching for misses on a smooth running motor. stock cam and all. no cyl miss showing in the data. my experience with misses is they show up under low rpm high load the most, this thing doesn't show any signs that would make me think anything is wrong drivability wise.

I gotta come up with a plan to at least find out which cyl it is. I have a temp tester, maybe I can find one tube cooler than the others.

hmm. hate to just throw parts at it.

[Alvin]

I don't think that screen shot came from that log

[???]

it's just a pic of the screen from my phone while it was idling, not an actual screen shot from reviewing the log after I took that while in the car real quick to send to a friend. I might have uploaded a different log, since i stopped and started the entire a few times while checking stuff.

I'll check. but it seems consistent? even old logs 4 years ago with stock exhaust show it, I was looking thinking maybe a header leak in one cyl. but it was still there.


thanks for looking. I'll fire up the laptop and double check there's a good log of it.

[edcmat-l1]

Post a fresh log.

[???]

started log from a cold start but then realized i didn't add missfire data, stopped log and added. did not shut down the car. so 2nd log is the same start.


got quick video of it idling too, incase someone hears something i don't

[???]

https://youtu.be/jnAbpkRRY8M?si=jLmsUj1pdRIxgQK-

[edcmat-l1]

100% that's a miss on that bank.

[???]

OK, thanks. I'll dig into it.

any guess on a cyl from that?

maybe I'll just do. plugs anyway, even thou pretty new and change everything left to right while it's apart.

you think it's worth doing a compression test?

[edcmat-l1]

It depends on what's been done to the vehicle. If you've recently done anything with the plugs and/or wires 100% it's installer error. Either cracked plug or a plug wire not snapped on tight enough.

[Alvin]

I'm not seeing a miss really.

Right click both o2 sensors in the channel list and make sure both are polling at the same rate. Also check the heater fuse just in case.

[edcmat-l1]

misfire bank 1.jpg

Regardless of sample rate that's a misfire on bank 1.

[Alvin]

I disagree.. but that is what is nice. We will still be friends

lol

[Cringer]

I'm not seeing a miss really.

Right click both o2 sensors in the channel list and make sure both are polling at the same rate. Also check the heater fuse just in case.

Export log to CSV, no interpolation...both O2 channels are polling at the same frequency and have timestamps that average .033ms (about 30 Hz)

[verlon]

I'm not seeing a miss really.

Second.

I'll bet for a faulty injector.

[Alvin]

Export log to CSV, no interpolation...both O2 channels are polling at the same frequency and have timestamps that average .033ms (about 30 Hz)

I'm not sure that will positively ID that.

There was a HPT version or something where one bank o2's were set to default poll much faster than the other side. I wanted to make sure that wasn't the issue here.

[???]

I'm not sure that will positively ID that.

There was a HPT version or something where one bank o2's were set to default poll much faster than the other side. I wanted to make sure that wasn't the issue here.

how do I check that?

how do I check that?


I found a log all the way back from 2017 and that side was still jagged.

not that it couldn't be an injector or something too