O2 Sensor gone bad? Or Maybe Something else?

[jspec]

Well I have searched and I don't want to continue on someone else problem as mine is a bit in consistent. 1st off my car is Throwing 2 codes PO141 and PO 443. PO 141 is O2 Heater circuit Malfunction ( Bank 1 Sensor 2) I believe this is the rear O2. The po 443 is the EVAP Emission Control System Purge Valve as it is unplugged. I was getting in consistant spark which I though was the coil pack. The car will run fine sometimes but as of late is hesitates and stumbles. I have to floor it to get it to move. When it is doing this it backfires and pops. Is this limp mode?

This is what I have done so far:

I swapped out the coil pack, PT, and the Cam Angle Sensor with known good units and the problem prosists. I boost leak tested it and found the Throttle shaft seal leaking I fixed those. I boost leak tested it to 30 psi and all is good now.

I think it maybe a bad O2 I have a brand new front O2 sitting here but I don't want to install it if my current one is fine. Any ideas?

 

[dragnby]

How did you pull your codes?? obd reader or your local parts store or by the blinking of the check engine light?

 

[jspec]

Well autozone does it for free but I picked up a scan tool on ebay for about $30 shipped to me. It is a Jem automotive J100 OBDII/ EOBD Scan tool.

 

[dragnby]

I know this might sound crazy but did you check your timing or your catalict converter??

 

[jspec]

Timing is set right and I have no convertor on the car.

 

[jspec]

MVI_9030.flv - Video - Photobucket - Video and Image Hosting

I replaced the injectors today and this is how it is running! Anyone?

 

[97GSRyan]

I would test your front O2 sensor... It controls your A/F so if it's going out you might be running rich. AutoZone's ALLDATADIY has a really nice explanation on how to test it <a href="http://www.autozone.com/servlet/UiBroker?ForwardPage=az/cds/en_us/0900823d/80/1c/c3/3f/0900823d801cc33f.jsp">here</a>. I'm thinking fuel mixture because you replaced the injectors and it got worse. (At least I hope that video wasn't better!) Keep us posted

 

[jspec]

Looks like a good test! I have a brand new front O2. I guess I will just replace it. It got worse when I installed my 95 ecu with dsmlink. The injectors didn't change anything. Just verified another piece of the puzzle. I may have a bad ground in the ecu.

 

[97GSRyan]

Ah, I see.. Well ECU's are far out of my league, so good luck and let us know how it pans out.

 

[blcknspo0ln]

Looks like a good test! I have a brand new front O2. I guess I will just replace it. It got worse when I installed my 95 ecu with dsmlink. The injectors didn't change anything. Just verified another piece of the puzzle. I may have a bad ground in the ecu.

bank 1 sensor 2, is in fact your rear o2. Did you eliminate your rear o2?

As far as DSMLink, did you tune your global fuel settings + deadtime yet? Did you designate the correct base settings for the car when you ordered your EPROM/DSMLink?

 

[jspec]

bank 1 sensor 2, is in fact your rear o2. Did you eliminate your rear o2?

As far as DSMLink, did you tune your global fuel settings + deadtime yet? Did you designate the correct base settings for the car when you ordered your EPROM/DSMLink?

Rear o2 is in. There is no cat so it should throw a code. Dsmlink is set for 450s and I now have 550s but it is still running the same. The code I am getting is something about the rear heater circuit. The thing is I read the rear o2 will not effect how the car runs it will only throw a cel. I am going to replace the front o2 tommorow and see what that does.

 

[BringBackDSM]

In my experience, when the fron o2 sensor when out, it made me run a little rich a low throttle, but not even a lot. I really don't think that's your problem.

The rear o2 also will not affect anything. It's there to make sure your cat is working right.

Your tune may be your problem. Try setting up dsmlink right and see what that does.

 

[jspec]

Nah the dsmlink isn't it. It runs the same on the stock ecu. I do think it could be a bad ground in the ecu area.

 

[blcknspo0ln]

Rear o2 is in. There is no cat so it should throw a code. Dsmlink is set for 450s and I now have 550s but it is still running the same. The code I am getting is something about the rear heater circuit. The thing is I read the rear o2 will not effect how the car runs it will only throw a cel. I am going to replace the front o2 tommorow and see what that does.

Thanks for the lesson, at least you're correct about why the CEL is being thrown. So you're telling me that you had DSMLink base tuned for 450s and you upgraded to 550s on the same settings?

 

[jspec]

Thanks for the lesson, at least you're correct about why the CEL is being thrown. So you're telling me that you had DSMLink base tuned for 450s and you upgraded to 550s on the same settings?

lesson? I really need one of those!! On fixing this car. I shouldn't have even mentioned the link. It doesn't help or hurt the situation. The only difference is the antilock light blinks when I have the link ecu hooked up. I think it is a bad ground or loose wire. I just don't know where to check. My guess would be somewhere in the ecu as I have already replaced most of the conponents that could be doing this.

 

[dragnby]

did you check your throttle position sensor??

 

[97 gst turbooo]

sounds no good. my car ran just like that and culprits were a bad o2 sensor on the housing and a throttle body gasket and also a bad MAF sensor.

 

[jspec]

I forgot to close this out! I solved this problem yesterday. I went to check the O2 sensor harness side. The wire colors where all wrong. I then looked around and found that the o2 sensor plug was plugged into the cruise control. Needless to say I swapped em and all is good.

 

[viprez586]

For future reference and knowledge O2 sensors rarely go bad. If you suspect it is bad or are getting false readings from your O2 sensor, remove and clean with rubbing alcohol. So to clarify, when they go "bad" they're really just clogged or dirty.