SMOG check - Car not in Ready Status - Failing SAI and O2 Sensor

[pike1181]

Hey guys,

 

So I'm having this issue that is driving me crazy. My SAI (Secondary AIr Injection) and Oxygen Sensor are not reaching "Ready Status"

A little background about my car. 
2006 Boxster S 3.2L
FVD Exhaust system
GMS Headers with 200 cell cats - has all 4 O2 sensors attached.
996 throttle body and distribution hose
ECU Tuning Group tune

 

I had the car up in BC Canada since 2009 (although it is a US car) and had no problems passing the sniffer and obdII tests - both before and after all the mods except for the ECU tune. 

 

I went to get my emissions testing done last week in Texas and failed due to the 2 systems being in not-ready status. I figured it might have to do with the cat delete (ROW) configured in the tune. I sent my ECU back to ETG in California and had them re-flash my ECU in order to re-enable the O2 sensors. 
I cleared all codes and figured I would start fresh. I drove the car about 120 miles and attempted to follow the drive cycle mentioned in the forums but it was really tough with the roads out here. Everything is in ready status except for the SAI, and the O2 sensor. I can manually start the SAI using the Durametric system so I would believe the pump is not bad; however, I'm not

sure that I"m hearing the SAI start up when I cold start the engine.

 

For testing purposes I unplugged my O2 sensors from both bank1 and  bank2 and they both threw fault codes which confirms that the ECU tune re-activated my sensors. 

 

I've uploaded a few pictures with the results from a OBDII app as well as the Durametric Software to my Google Drive. I'm not quite sure how to interpret the Durametric Voltage results - especially the negative 50 V and -127V - seems quite odd. 

https://drive.google.com/open?id=0B4ncE-o5M02DeUlLZVlxRV9hX3c

 

Any help or guidance will be appreciated as I'm out of ideas.  

 

Thanks,

Joel

 

[JFP in PA]

OK, couple of points:  When you reprogrammed the DME, it has the same effect as clearing all codes, namely the car needs to run for some miles and drive cycles before the SAI will reset.  On some of the early 986's, it could actually take a couple hundred miles before this happened, so do be surprised.

 

As for the O2 sensor issue, Oxygen sensor voltages should be between 0.04v and 0.79v.  The DME is looking at the relative voltages before and after the cats to confirm the car is in air/fuel spec.  One sensor (the one behind the main cat) will produce a fairly steady voltage, while the one ahead of the cat will cycle in a sine wave like fashion if the cat is in good order:

 

[JFP in PA]

If the cat is bad, the two sensors will pretty much mirror each other:

 

[pike1181]

Thanks for the info JFP - nicely written. 

Any tips on how to monitor each of the sensors with Durametric? I've been winging it and not quite sure what the titles that I need to be monitoring/logging are for O2 before cats and O2 after cats. 

If the cats are bad, would the SAI simply not turn on at all? We're allowed to have 1 failure here in Texas so as long as I can get either the O2 or the SAI to turn on, I'll be happy - although I would like to get to the root of the problem as well. I've uploaded some O2 results from my OBDII Wifi app. - Again, I'm not sure whether these are pre or post cats. Bank2 displays "Not Used" when I try running a monitor on them. I wonder if that's relative to my issue. 

Edited December 22, 2016 by pike1181

[JFP in PA]

The SAI works independently of the cats, so cat performance will not effect it in anyway.

 

With your Durametric, you should be able to select both O2 sensors on each side, then graph their voltages in real time with the car running.  If everything is correct, you should see a graph trace that looks like my first example; if one or more sensor is off line, it will be obvious.

[pike1181]

Thanks JFP. I'll try to figure out where the 2nd set of sensors are listed in Durametric and try to run that test tomorrow. I'll post the results once I find the time to do it. 

On another note, I noticed yet another weird issue - my RPM's would fluctuate while idling. The fluctuation is noticeable as the car gets quieter, has a slight hesitation then back to normal - it does this in a regular pattern - quite similar to the O2 voltage regulation actually. 

[pike1181]

Thanks JFP. I'll try to figure out where the 2nd set of sensors are listed in Durametric and try to run that test tomorrow. I'll post the results once I find the time to do it. 

On another note, I noticed yet another weird issue - my RPM's would fluctuate while idling. The fluctuation is noticeable as the car gets quieter, has a slight hesitation then back to normal - it does this in a regular pattern - quite similar to the O2 voltage regulation actually. 

[JFP in PA]

You may have a questionable sensor, but without proper data, we are guessing.