In trying to track down split BLMs, I noticed the right O2 seems lazy. See red line in graph. Does this look like it's failed? 100ms sample rate.



O2's were both replaced after break-in, about 1000 miles ago. Several BLM's on the right side are 108. See second graph.



Could a failed right O2 sensor explain all this?

Response was great on both O2s when new, but I've run Torco Accelerator, which turned the plugs, and presumably the sensors, orange. Could that explain the failure? What is the preferred sensor type to run? Is GM Stock fine?

Thanks for any help.

 

If you run the car till it is good and warm and the sensors do not flucuate rapidly from 100 to 900 you probably have a bad sensor. The connector can go bad or get burnt so if you replace the sensor and it still does it you probably have a burnt wire down the line. Most recommend the AC Delco OEM factory ones and they are about $40 each so the cost is OK. I have read many posts on aftermarket ones and they can have all kinds of problems and they aren't much cheaper. It is important to have the right thread compound on them when you put them on otherwise you could have false readings or inaccurate ones.

 

is this at idle?

try graphing them at 1500 rpm, if it is still lazy, replace the sensor

 

This was from a road load, steady light throttle. I watched them more in real time today. Sometimes they look better than above, fluctuating .400 - .800 ish, but not like new. Not as fast, or as wide of a swing. Wires still routed ok, not too close to headers and wrapped. Looks like I failed the new sensors somehow. Thanks guys.

 

UPDATE: I'ts been about 2 weeks, on those same O2s, and yesterday after the track I developed a bad lean/bucking at low throttle, and several BLMs at 108. Replaced the O2 sensors today with Delphi parts, and driveability is back to normal, better than ever. So, it was bad O2s. They only had ~2k miles, and were Bosch. I suspect either Torco Accelerator (2 tanks), or the sensor-safe high temp orange RTV I sealed the exhaust band clamps with a couple days ago, may have fouled the sensors.

Now, ironically, I have a solid 160 BLM at idle, as opposed to the 108. Arrrrgh! Hmmmm, maybe if I put one old sensor back in, it'll average out? JK. I'll look for exhaust leaks.