HO2S11 Reading Incorrectly

[Supercharged111]

Buckle up for this one. Last year my dually developed a nasty misfire. Seeing how we were getting ready to move, I didn't really mess with it. Figured the 4 year old copper plugs needed replaced. Wrong. Among other things the engine had eaten ANOTHER cam, a 212/218 sized unit. I replaced it with a 211/230 GM 454HO cam in hopes of a quieter valvetrain with a stock base circle. I seem to have gotten that. The truck needs a tune to be proper with the new cam, but I still have a persistent random misfire in #1 that I can't nail down. I've swapped injectors 1 and 3 around and only #1 has the misfire. I had the heads off when I did the cam and ended up lapping the valves (#3 was also misfiring and was leaking out the intake valve as it had developed some combustion deposits on the valve seat, plus that's the cam lobe that was wiped out). Compression is good on #1. The old head and intake gaskets were not leaking, I have no reason to believe the new ones are either. The truck got plugs, wires, cap, and rotor last year prior to the move. I got to wondering if I had a failing injector driver so I swapped in the 411 from my 1500. Since they both run 12212156 based COS5 it was a simple calibration flash and away I went. No change with the misfire, but now all of a sudden HO2S11 is in absolute lockstep with MAP.

LS1B_0039.pld

I came back, inspected wiring, ohmed, nothing is shorted to anything far as I can tell. Swapped O2 sensors left to right, same exact thing. Finally I grabbed a cheapo scanner off my toolbox and hooked it up. Money, B1S1 is oscillating and not pinned around 200mV. So I restarted the scan software and now it's pinned around 30mV. Mind you the wideband is installed in bank 1 and it's saying all is well minus the state of the tune. Maybe all I need is a crank relearn and this isn't a misfire after all? I certainly don't feel it going down the road. Either way this whole sensor not reading correctly in the software is no good and will only continue to lead me astray with any logging or tuning efforts.

[dhoagland]

Logging too many pids?

[Supercharged111]

Logging too many pids?

It says 29, but I only count 19?

[dhoagland]

I'm far from an expert.
But some of the enhanced pids add more than one to the list. I believe its due to needing supporting pids to gather the data.

Probably not the answer, but just pick one or 2 you don't really need and see if it makes a diference

[Supercharged111]

Weird, maybe a V8-ism? Thinking back certain PIDs used to make me select other supporting PIDs in 7.5 and this time it didn't ask any questions.

[dhoagland]

I know on the Dodge & GM diesels I have done certian parameteres made the count increase by 3 sometimes...

[Supercharged111]

Well that ended up being it. Dropping a single PID would reduce the count by a few a pop. It got the O2 cycling again, so back to troubleshooting the mechanical issue at hand so I can dial in the tune on this unit. Now that I saw how weird it could make a single PID, I'm thinking the data that I collected also trying to chase where my timing was going is probably also compromised. I bet this is probably covered in some V8 reading I didn't do.

[dhoagland]

Thanks for letting me know...
Good luck with the rest of your diagnosis

[nonnieselman]

Yea that red bar at the bottom lets you know you have too many PIDs.
If you go over that number it will make the scanner act very weird and return bad data.

[Supercharged111]

Yep I saw that, counted 19, and pressed on anyways. I seem to recall going over 24 on the 7.5 software and it not going wonky like this. Maybe I got lucky? Or maybe V8 is somehow different and really doesn't like going over 24.