signs of a bad o2 sensor

[Fast95GSX]

I've been having problems recently and have a clip from my log.
Before I go and buy an o2 sensor, does this look like it is going out to you?

 

[99gs420a]

I think you should test ## o2 sensor. But your logs do look alittle funky with the o2.

 

[snowborder714]

Grab an idle log with the car up to operating temperature. Look for the o2 to cycle between .05v and .95v. If it doesn't, then it's not working.

 

[99gs420a]

What if at idle it is just 0.00v ?

 

[phunny]

What if at idle it is just 0.00v ?

that would be dead

 

[snowborder714]

Yup. If you watch it while the car warms up and it doesn't move, it's dead. Or possibly unplugged.

 

[gofer]

The o2 sensor plug will fit into the bottom of the cruise control solenoid thats mounted on the passenger side strut tower. If you're getting 0v from the front o2 make sure its plugged in like Brian said, as well as making sure you didn't get the CC plug and o2 sensor plugs crossed.

The front o2 sensor should be plugged into this connector http://www.dsmtuners.com/forums/151542283-post40.html

 

[MY1GDSM]

Anyone else notice the Wideband readings as well?

seems odd... it's frozed at 13.2:1 most of both logs except a few spots where it jumps to 15.8:1,

Two dead o2 sensors?

 

[gofer]

If the ECU is stuck in open loop then FT's aren't going to cycle, especially with a front o2 sensor thats showing 0v (LEAN) so the ECU is trying to richen up the mixture. I can't look at the log (work computer) but the WB reading a 13:1 AFR would seem like it makes sense to me, if the above theory is true.

 

[MY1GDSM]

His combindedFt went to +16.8 in one of the logs an their was nearly no change in the W/b reading while the stock 02 was reading .70-90 volts.

Seems to me more like a dead or unplugged W/b 02.
As well,
Maybe the Op has the wrong wideband selected Since AEM gauge usually default 14.7 when unplugged...

 

[Fast95GSX]

I replaced the front o2 sensor yesterday and it seemed to help. I still am getting flaky results from the wb reading though. My wideband gauge pretty much hovers around 15.5(+-) at idle and the log shows 13.3(+-).

I have it running through the rear o2 in the log and gauge set to default P0. Should I select P4 or another one?

I really think my wideband sensor is also on the fritz and I will probably look at that next.

 

[MY1GDSM]

The narrow-band o2 is obviously working correctly now...

But, No leave the W/B on PO it's the correct setting.

Also are you sure your not logging the BLUE Serial Output wire an have the WHITE Analog Output hooked up?

 

[Fast95GSX]

The narrow-band o2 is obviously working correctly now...

But, No leave the W/B on PO it's the correct setting.

Also are you sure your not logging the BLUE Serial Output wire an have the WHITE Analog Output hooked up?

I'm not sure how the wb is wired. How do you think I should config it in ecmlink? I took it for a run after some tuning and runs alot better but still not quite right. Here is a clip of the log and you can see it is quite rich and after I let off the gas the Mafraw, AFRatioEst and fuel flow all go crazy again.

Do you think it is my Bov not performing right.

 

[snowborder714]

I'm not sure how the wb is wired.

Pull the driver's side lower center panel that covers the ECU. Look at the top plug (closest to the radio). Find which wire has been spliced using this article. Look around the 75/76 area.
http://www.dsmtuners.com/forums/articles-tuning-ecu/281763-2g-turbo-ecu-pinout-w-wire-colors.html

In link, it's being input into the front o2 spot, which shouldn't work right if you have a factory front o2 sensor. If you had it input in the front o2 spot, I would expect to see you using the narrowband simulation via link. Let us know so we (or at least I) can understand what is going on with your setup.

 

[MY1GDSM]

In link, it's being input into the front o2 spot, which shouldn't work right if you have a factory front o2 sensor.

Not sure why they changed it... .

But, In the first 3 logs the OP posted they had Ecmlink logging the W/b from the Rear o2.

 

[Fast95GSX]

Yeah I had it wired to the rear o2 in the first few but was reading in ecmlink .2 lower than what my gauge was showing at idle. I guess I have more figuring out to do. I will check tomorrow which way it's wired when it's daylight out.

Thanks for all your help and this is a great forum....

 

[snowborder714]

That's normal, and one issue with the AEM unit.
aemwb [ECMTuning - wiki]

 

[Fast95GSX]

I am still having problems with Tial Bov not working right as you can see in the pull log. Notice when I let off gas around 5 - 8 seconds in the log. My BoostEst does some weird things when coming off boost.

The BoostEst goes up and down along with the MafRaw and Fuel Flow so It doesn't look like it is releasing properly or even opening at all. I have the Tial Bov venting to atmosphere and not sure what spring is inside. The guy that had the car before me had a Gm Maf along with a blow-thru setup with Tial 38mm wastegate. Now the car has the stock Maf and is running 10psi off the internal wastegate.