Z06d

I've attached two log files. In each log, a different o2 sensor was installed in the B2S1 location. Log 1 was with a Denso sensor, and Log 2 was with an original REAR sensor up front.

Both are from a cold start and last about 3.5-4 min. Is that long enough?

The graphs vary significantly between the banks. B1S1 appears to be switching more rapidly with steeper slopes on both logs. On Log 1, B2 has higher and lower peaks, but switches more slowly. On Log 2, B2's signal remains more towards the mid range, but appears to switch more quickly than the DENSO in log 1.

From these logs, can the health of the o2's be determined? What exactly should I be looking for? I'm fairly new to reading this info, so your replies are greatly appreciated!

Thank you!

NOTE: The HPT config file extension needs to be renamed back to .CFG from its current .txt extension to be usable in HPT (can't upload .cfg for some reason)

Z06d

...attached a couple jpg snapshots of what the charts look like for those without HPT:

06X6spdGTO

iTrader: (6)

Well when you start the vehicle it takes the o2s a little while to warm up. I would say your time line looks about right depending on when you command the PCM to hit Closed Loop ECT.

At Idle the o2s are going to vary in every application and day depending on Ambient Temps. On a hotter day the o2s will tend to read quicker due to the sensor being hotter. Look more at when you are driving the car as the EGT's are higher when under throttle. As long as the LTFT dont have a large offset from one another your more than likely fine.

Was the car throwing any codes to lead you to think that the o2s were bad??? What was your reasoning behind the swap?

Z06d

Note: Long tube headers installed.

Originally DTC P0135 & P0153 were set (both banks). That was with the two Denso's up front. Then I swapped in a used set of rear o2s (condition unknown) from a non running '03 z06 project car. After that, only one DTC remained. I then swapped the o2 from the bank associated with the DTC to the other bank. The DTC followed along... That sensor was definitely bad. It's reading rarely ever went below 300mV or above 600mV.

So, to replace that bad sensor, I pulled the existing rears off, plugged the bungs, and installed one of them in the B2S1 (log 2). Now, it hasn't thrown a code yet, but I haven't really given it much opportunity to do so. According to the service manual, the DTC can only set when "Scan tool output controls are not active", and I've been logging every time. I just realized this criterion exists, so I'll let the car run for a bit with the scanner unplugged to see if anything pops up.

Btw, I believe that the test associated with these DTCs is completed within the first couple minutes of run-time from a cold start.

Bottom line, I'm just concerned because B2S1 looks lazy relative to B1S1. Does anyone out there agree or disagree?

sicksspeed

iTrader: (2)

Not really sure were your at with your diag. but why not swap left to right to see if the o2 is lazy on both sides.

RonSSNova

iTrader: (3)

I agree. If the ugly trace follows the sensor, then it is likely not working correctly.
If it doesn't, then I bet you have a bad connection.
ron

Z06d

FYI, B2S1 did end up throwing a P0155 once I turned it on from a cold start with the DLC unplugged.

I then swapped each o2 to the opposite bank, and the lazy & good signals followed along respectively...

I knew it had to be the sensor, because I checked the continuity of each circuit from end to end (sensor connector to pcm connector) and everything was good.

Now to find a new sensor....

Any idea:
-what's the consensus on the best o2 for long tube headers?
-who manufacturers the OE sensor for GM?
-part #s?
I'll do some searching, but if happens to know, that'd be great!

RonSSNova

iTrader: (3)

The GM parts although they say AC Delco are made by NTK/NGK. I just put new ones on my C5.
They are the new planar style. Heat faster and draw less current for the heater.
Can you run normal fronts? Or do you need the extra cable length?
I don't have the part number handy for the front replacements.
BTW, I am just firing up a complete new combo listed in my sig. I just wanted to start withnew parts.
My long tubes are XS power, but would be the same as AR as far as sensor lead lengths are concerned.
From a cold start mine fire off at 1:20.
My headers are coated.

Ron

Z06d

Hmmm. NTK/NGK? Quite possible, but I did read elsewhere that they're made by Denso. Where'd you hear NGK?

I bought the car recently, and it came with Denso pre-cat o2s up front. They were throwing codes, so now I'm going with REARs up front as per LG Motorsports recommendation (as well as the general consensus).

Yes, I can run normal length fronts, but I don't want to throw away money as they'd surely throw codes.

I haven't looked into XS power LT's. Are they true long tubes, or more of a mid length?

If you're using HP Tuners, would you be willing to upload/send me a log of your o2 data from a cold start? I would be nice to see what the trace of a fresh pair of GM o2s installed in long tubes looks like. You could attach the hpl to a reply here, or email it to me (I'll PM you me address).

bayer-z28

iTrader: (14)

^ I just don't run the rears. Have the pass side in as a plug, but running the sims. The rears are only cat-check sensors. I don't think they are narrow band O2's.

And I'm running a set of Delphis for my regular O2's. Got em online for a decent price. And don't really pay attention to the O2's when they're "cold." When your PCM commands closed loop, that's when the sensors should be warmed up. They're basically batteries and over time they go "dead" and get lazy.

06X6spdGTO

iTrader: (6)

You can command closed loop when ever youd like, your o2 have no bearing on when the PCM starts to read off o2 values. Personally if you plan to go with a large cam in the future just tune in Open Loop. If you like the o2's none of them really run that well during idle/low speed. Even decent widebands have a larger degree of error during these times. Id replace with the Bosch replacement number lean the car out a touch at idle/low speed cruise and fine tune the top end.

Just me.

bayer-z28

iTrader: (14)

^ Should be tuning in OL anyway, that way you're not fighting the computer's corrections, even with EQ @ 1.00/stoich when it's warmed up.

06X6spdGTO

iTrader: (6)

If you want you can leave all the stock PCM OL equations to factory settings. Lock out CL function by setting the ECT vs IAT to 255*F across the board.

then build a custom PID logging error from 14.7 (in %) vs the reading on your wideband. this way when you enter WOT (ie 90+KPA area) the computer can still build fuel in accordingly if your MAF was failed out. this is the format I tend to use for the extra level of safety, works well for street tuning where it is alot harder to hit the higher MAP cells with good data.

Basicly all your doing is targeting 14.7 AFR in all your cruising cells. Just a little different way of cutting the cake. Ive havent had a problem doing it this way yet but only done it on a 456whp 02 Firehawk, 460whp 01 Z06, and 530+whp GTO.

Ive found after tuning to get the stoich you want and turning o2s back on with larger cam'd cars they tend to start to build positive fuel trim in low speed cruise/idle situations which will throw the positive value on top of the car PE when going WOT. Generating less power! Just my .02cents on tuning in Open loop and leaving it that way!