Help! Replaced O2 sensors still have CEL???
 

OK, so I pulled the following codes using a Peake code reader:

19 (table number)
C6 CAT CONVERTER EFF CYL 1-3
CA O2 SENSOR CONTROL LIMIT CYL 1-3
F0 MISSFIRE #3
E4 O2 SENSOR ADAPT LIMIT CYL 4-6
E3 O2 SENSOR ADAPT LIMIT CYL 1-3
EE MISSFIRE #1
F3 MISSFIRE #6
EF MISSFIRE #2
F1 MISSFIRE #4

So I bought two new Pre CAT Bosch O2 sensors from NAPA today and installed them using the great DIY write up here. Everything seemed fine and the car was running OK. My wife drove me down to the Motorcycle shop (~25 miles) to pick up my bike and then she drove it home. On the way home the CEL came on again. I just rechecked the codes and they are basically the same??? WTF? :hmm: :cry:

Any idea what else this could be? Could it be the Post CAT O2 sensors? My car is a 2003 and only has 56k miles. I was surprised the O2 sensors went bad already. :( I just don't get it and despise taking it back to the stealership... (They wanted $160 each for the same O2 sensors that Napa had for $95 each).

So now it shows:

19 (table number)
CA O2 SENSOR CONTROL LIMIT CYL 1-3
C6 CAT CONVERTER EFF CYL 1-3
E4 O2 SENSOR ADAPT LIMIT CYL 4-6
E3 O2 SENSOR ADAPT LIMIT CYL 1-3
EE MISSFIRE
F0 MISSFIRE
EF MISSFIRE
F1 MISSFIRE

Any ideas what I should look at now?

This seems eerily familiar to me. I'll give you a short story: I had the O2 sensor codes and a bad oil leak from somewhere under the intake manifold. I replaced both pre-cat O2 sensors and the oil separator (which requires removal of the intake manifold) and the car ran like a dog afterwards, with ... pretty much the same codes.

I assumed that it was the intake manifold maintenance that had caused the problems, because it was WAY more complicated. So I redid the intake manifold 3 times looking for vacuum leaks, dirty connections, etc. I ended up cleaning the ICV, throttle, cam and crank position sensors, fuel injectors, and a host of other things, to no avail. I did find a couple of small vacuum leaks, but nothing that should have caused the indicated problems.

So I took it for a drive to the mechanic to get it looked at by a pro. 15 minutes into a 16 minute drive, the car suddenly started running normally. Idle smoothed out, misfire went away, it was perfect. I never figured out exactly what it was that caused the problem, but I suspected something in the computer needed some drive time to reset the adaptation limits to the new O2 sensors.

As I read your post, with all the same error codes and no oil sep maintenance, I begin to suspect that I might have been right. Double-check to make sure you installed the O2 sensors right, then take it for a drive.

If that doesn't fix it, I'd start looking for a vacuum leak. Check the intake boot between the throttle and the MAF; that's the common one.

Good luck.

Dan

try a MAF meter cleaning procedure also.

Thanks Performancenut and Dan.

I have an older Dinan CAI with the larger throttle body and stage III software. I pulled the intake/MAF tubes apart and cleaned the inside of the pipes and all the clamps almost to the throttle body. No cracks or other issues that I could see from flexing the tubes. So I put it back together and started the car then tried using a (unlit) propane torch spraying the gas around different areas seeing if the idle increased. There may have been a slight increase when I sprayed gas around the rectangular box that hangs on the side of the intake manifold above the throttle body (right behind the dipstick). Not sure what this is, cruise control? RealOEM.com shows it as the (idle?) "adjuster unit"? part number 7 in the first pic.


I also found that the big round cannister (RealOEM calls it the Emmission Control - Air Pump - part number 1 in the pic) next to the washer fluid reservour has two broken mounts and moves around. I use some zip ties and secured it to the bracket. All of the hoses and connections look OK.

I will try and get some MAF cleaner tomorrow and see if that helps... I have a can of "brush" cleaner for the electric motors in RC cars; I may give that a try tonight...

I drove the car around again today with no issues... until I stopped at the drive through ATM. After sitting and idling for a few minutes I got another CEL it threw the same codes. I immediately cleared them again and drove home.

When I got home I did not have a CEL but I checked for codes anyways and found the E3 and E4 codes again. :bawling:

E3 O2 SENSOR ADAPT LIMIT CYL 1-3
E4 O2 SENSOR ADAPT LIMIT CYL 4-6

Still open for suggestions...

I have seen the crankcase vent valve develop a vacuum leak and cause problems similar to what you describe. Sometimes a smoke test is needed to find the source of a vacuum leak. Do you have a poor or irregular idle?

Yes, after clearing the error codes it will run/idle normal for awhile (~600-700 rpm on the tac). Then after awhile it starts running rough at idle and the tac needle bounces around a bit (+/- 100 rpm), overall rpm may drop to around 500 rpm. I have not had it die because of the rough idle, but in gear with my foot on the brake it sometimes feels like it's about to. Also cleaned the MAF with my electric motor contact cleaner last night and have not noticed a difference.

Where is the crankcase vent valve? Can I get to it easily or is it buried?

Under the intake; it can be changed without the intake removal but is more challenging. There are some good DIY procedures on this site. Make sure you check the rubber intake elbow for cracks and leaks first.

Just wanted to follow up for anyone that finds this post through a search. The problem ulimately was that the "Idle adjuster" broke. This is number 7 in the attached pic and slides into the side of the intake manifold above the throttle body. The base of the door/gate that rotates to open/close the airflow broke off the the stub that operated it. This was causing a vacuum leak directly into the side of the intake manifold. When I bought a new one at the dealer (~$215+ tax) I was surprised they had it in stock. The parts guy said they had 18 of them on the shelf! So appearenly this is a common thing to break. Two screws and one electrical connector. About a 5-10 min job to replace it.

any updates since? I might be running into the same issues as you, i have it down to the same part that you replaced(#7) and the cam position sensor..thanx

Thanks for the link to here... these are my same issue as his. I'll check my adjuster unit this weekend, this might have been my issue all along.

Luke,

When you replaced "Idle adjuster", did it fixed these error codes?

E3 O2 SENSOR ADAPT LIMIT CYL 1-3
E4 O2 SENSOR ADAPT LIMIT CYL 4-6

Yes please answer...I have the same two codes...this has to be a easy fix once someone finds it for the e46s...too many throw those codes...

Any updates. My 330 is throwing the same codes. I really don't want to take it to the Stealer$$$$$$.


Kevin

Surprised jbeurotech hasn't commented on this yet. :)

I recently ran into same E3 E4 code. I did what every one did, replaced the O2 sensor and got the same results as everyone did: the code came back.

It's vacuum leak. Unfortunately it can be a hit / miss to find. I got lucky to find the majority of my vacuum leak was from the DISA valve (adjuster valve). Others find it in the intake hose / elbows. And there maybe many other sources. I did this sealing job and my codes are gone:

(more detail in this thread: http://forum.e46fanatics.com/showthr...774&highlight=

http://i237.photobucket.com/albums/f...g?t=1211402189

Yea, I sealed mine and also replaced the ICV, rubber intake boots, 02 sensors, cleaned MAF, etc. It really does sound like a vac leak so I just ordered the back grommet(seal) for the ICV and I'm checking the vac selonoid(under the manifold) and air pump. The car seems to run fine but it keeps throwing the same codes but never goes into limp mode:excited: Also the code it throws first is ICV "stuck"(new) then it will start adding down the list as time goes on. I'll report back as progress continues.

Kevin

Both of you might need a smoke machine test; the site of vacuum leak also releases the smoke and identifies the leak. This test is much more efficient than simply throwing parts at your cars. With the codes indicating a problem with both banks, the leak is certainly forward of the compression chamber.

where to get a smoke machine test performed?

Private independent repair shops and dealers too.

Update once again. I replace all the vac hoses and the rubber groumet behind the ICV. The vac lines behind and underneath the manifold were shot(crumbled). It's been a week and no codes yet!!!!!!


Kevin

how did you replace all the hoses???