Replaced O2 Sensor; still getting Code #11 and CEL; Please Help!

[RTICWOLF]

Hello everyone!

I need to figure this out on my new (to me) 92 Eclipse GS with the 2.0 N/A engine....cannot pass emissions and get my plates with the CEL coming on. I just put in a new O2 sensor because the car was flashing a code #11 when I hooked up the LED tester to get the codes, and the exhaust certainly smelled like it was running rich anyway. I replaced it and all the codes were clear (battery was disconnected for over a week while I did other work at the same time). I started the car and all was well, no CEL, but it still smelled rich. I drove it for about 10 miles and now its pulling the same CEL code #11 and the light is back on!!! Is it just a bad "new" 02 sensor or perhaps another issue I have not discovered just yet? I live where you have to pass emissions to get plates, so with a CEL I cannot register the car and start to enjoy it until that is fixed.
As a side issue, the car does not idle smooth when sitting at a light while in drive (automatic) or even reverse (when a load is on the engine). Once you start going its perfect. Its not like a constant miss, its erratic, kinda sputters and stumbles a bit, only does it once it is warm and the idle drops (normal idle seems to be around 600 rpm in gear). I did put new plugs in the car (also an air filter, PCV valve, fuel filter, etc). I ended up using just standard Bosch plugs, the guy told me at Auto Zone NOT to use platinum plugs as they could cause me issues with my engine.... Not sure if that is true, what do you all think on these issues? Really need the help, need to get that emission test done....

I did do a search for the problem, but was not able to find anything specific to my issue, at least on the searches I tried. I am not new to boards such as this, just new to this board and to this particular car and would love the help.

Thanks in advance!

 

[ddavisaf]

It's good they told you the platinum plugs are crap. It kinda surprises me they told you that. I would still recommend NGK BPR6ES though.
Your idle problem is most likely caused by your ISC located on the bottom backside of the throttle body. Replace it with a known working one and you'll be good to go on that end. As to the o2 problem, check all the wiring and make sure you don't have any melted wires. Make sure the O2 sensor connector is plugged in on both connectors. And make sure you don't have any pre-02 Sensor exhaust leaks.

 

[RTICWOLF]

After doing futher investigation, I found all the wiring to the O2 sensor to be intact. I was told from someone else that I should measure the voltage for the wiring harness with the key in the on position but the engine not started and that one of the four leads should measure 5 volts. I tested my harness and got one lead (the red wire) to measure 12 volts.
So, what is it supposed to read, 5v or 12v? I did order a warranty replacement O2 sensor and should have it today to replace the new one I just purchased since it could be faulty as well.

I also removed and cleaned the ISC and hopefully that will help the sputtering idle, I will let you know on that....replacing it is my next step if needed. However, I removed another unit that I first thought was the ISC....it was actually on the left side of the valve cover in front of the TB and was held in place by two 12mm bolts. Once I removed it I realized it was not the ISC, I actually do not know what it is for, but it seems to allow for some sort of adjustment because it can be turned either way (about 25 degrees of travel) and then tightened down where desired. Actually appears to be connected in some fashion to the rear cam, maybe not, but does this adjust anything? I am sure I did not put it back exactly in place as it was, but I have not started the car yet to know if anything changed since I do not have the new O2 sensor installed. Any help with this dilema would be greatly appreciated as I do not have a Hanes manual (had to order it).

Also changed the plugs to the NGK's....the parts computer said to gap at 44, I used the underhood sticker that said 39 to 43, so I split it and set them at 41.

Thanks again!

 

[steve]

The red wire to the O2 Sensor is battery voltage for the heater. Both of the black wires are grounds and the white wire is the sensor output.

It sounds like you removed the CAS from the intake cam. It's used to provide the ECU with cam/crank angle timing information. If you look at the side that fits into the head you'll notice that there are timing marks on the base of the CAS and the blade that fits in the cam. Set the engine to TDC cylinder 1 compression stroke and line the marks up on the CAS before installing it. follow the instructions for setting the timing to 5* BTDC to dial the CAS adjustment in.

Don't forget to measure the resistance of the ISC coils to make sure they are good.

Steve

 

[RTICWOLF]

Thanks Steve for the reply!

I actually got the engine at TDC and lined up the CAS perfectly last night, so at least my mistake in pulling it off was not a big deal. I am going to set the timing tonight along with the idle with the info I found on VFAQ, so hopefully all is well there once I am done and my idle is then smooth.

I do have one question about the O2 sensor. I got a new one and installed it, but I am just a bit unclear of the white wire on the vehicle harness. You said it was the sensor output, so I assume that it will NOT read any voltage on the vehicle connector side when testing with the sensor disconnected? The other two are grounds, so only the red will show 12v going to the sensor and the white is for the return back to the ECU? If that is all correct, why did that other person tell me to check for 5V? When I check the white wire, I get nothing with the key in the on position but not started...

Thanks again for all the help and direction, I am really starting to understand this car and engine much better....certainly a bit different than all the GM cars I have worked on.

 

[steve]

I do have one question about the O2 sensor.
I got a new one and installed it, but I am just a bit unclear of the white wire on the vehicle harness. You said it was the sensor output, so I assume that it will NOT read any voltage on the vehicle connector side when testing with the sensor disconnected? The other two are grounds, so only the red will show 12v going to the sensor and the white is for the return back to the ECU? When I check the white wire, I get nothing with the key in the on position but not started.

If that is all correct, why did that other person tell me to check for 5V?.

You might not get anything until the heater in the sensor gets it up to temp, and without the car running it would read very lean. The sensor creates a voltage once it get hot based on the amount of oxygen surrounding it. The less there is the higher the voltage.

I try not to comment on stupid things other people say when they don't have a clue.

Steve

 

[RTICWOLF]

Ok, thanks a bunch Steve, I thought that the 5V thing sounded odd, glad you were here to set it all straight. What you said makes perfect sense and now I know that my wiring is good too since I physically inspected it and correctly tested it.

I really do appreciate the help! Crossing my fingers now in hopes that everything will be fine once I get the timing and idle adjusted!