Maybe I'm just not meant to mod.

[Haywood]

I'm hoping I can finally find an answer to my issue. Ever since I changed my OEM x-pipe out, I've had numerous engine malfunction issues and limp modes. A little history first.

I installed test pipes on my OEM x-pipe and everything seemed to be fine for about the first 100 miles. After that, major engine malfunctions. I had a BPM tune so was able to see the errors. The same ones that I'm still having below. I then replaced with a Challenge x-pipe. Seemed to be better and then the issues came back again. After doing some research, I felt that it was a bad O2 sensor on the drivers side upstream. I ordered a new one and replaced it. Again, I thought the issue finally went away and now it's back.

A couple of things to note:

1). It only goes into limp mode at idle speeds, i.e., at stop lights. The idle starts to get rough and then bang into engine malfunction mode.
2). It seems to be worse during the hot weather when the engine temps get over center line.
3). Important mods are BPM tune, MS intake, and Challenge Race X-pipe.

Now, I've taken it to 2 dealerships and 1 independent shop. They have all come back with different opinions, but nobody has been able to pinpoint where it's coming from. I still suspect it could the o2 sensors, but I'm not sure anymore. Thanks for taking a look and I hope someone can help me!

// 1) 2751 Lambda sensor error pump current cable VKAT bank 2
// 2) 2B39 Combustion misfire with cut-out cyl 5
// 3) 2B3A Combustion misfire with cut-out cyl 6
// 4) 2B3B Combustion misfire with cut-out cyl 7
// 5) 2B3C Combustion misfire with cut-out cyl 8
// 6) 2B41 Combustion misfire with cut-out several cyl
// 7) 2B57 Motor emergency programm activated
// 8) 2796 Motor emergency programm activated
// 9) 2B46 Combustion misfire with emissions deterioration cyl 5
// 10) 2B47 Combustion misfire with emissions deterioration cyl 6
// 11) 2B48 Combustion misfire with emissions deterioration cyl 7
// 12) 2B49 Combustion misfire with emissions deterioration cyl 8
// 13) 2B4E Combustion misfire with emissions deterioration several cyl
// 14) 275E Lambda control stop error bank 2
////////////////////////////////////////////////////////////////////

Edit: I forgot to say that my car also backfires when the car is cold.

[Patrón]

can't believe the mechanics can't tell which o2 is out, but i believe that is what the problem is...

[Haywood]

Originally Posted by Patrón

can't believe the mechanics can't tell which o2 is out, but i believe that is what the problem is...

Thanks. Can you elaborate on your reasoning?

[pbonsalb]

Since the bad stuff is happening on one bank and affects all cylinders there, one explanation makes the most sense, like one bad 02. If just 1 or 2 cylinders were bad, I might think worn plugs or coils.

Try swapping primary 02 from one bank to the other. If problem goes away on 5-8 and moves to 1-4 then you know the problem.

[Haywood]

Originally Posted by pbonsalb

Since the bad stuff is happening on one bank and affects all cylinders there, one explanation makes the most sense, like one bad 02. If just 1 or 2 cylinders were bad, I might think worn plugs or coils.

Try swapping primary 02 from one bank to the other. If problem goes away on 5-8 and moves to 1-4 then you know the problem.

Thanks. I read that bank 2 is on the drivers side so that's the one I replaced. I hear what you're saying, but if I'm not getting errors on bank 1, do you still think it's worth swapping?

[jeff@autocouture]

it definitely sounds like a bad 02, a lot of times we've seen customers strip them when swapping pipes, try swapping them around as stated previously

[BPMSport]

Definitely sounds like a bad pre cat O2 sensor. Other other thing it could be is a faulty throttle actuator on the second bank, but I would say it's a 95% a damaged oxygen sensor on that side. I wouldn't bother swapping, just replace it with those odds.

[BPMSport]

Also just FYI:

VKAT = VOR (Before) Cat
NKAT = NACH (After) Cat

So the upstream sensors are fine, it's a precat sensor causing the issues.

Hope this helps, easy fix in this case.

[Haywood]

Originally Posted by Mike Benvo

Also just FYI:

VKAT = VOR (Before) Cat
NKAT = NACH (After) Cat

So the upstream sensors are fine, it's a precat sensor causing the issues.

Hope this helps, easy fix in this case.

Thanks, Mike.

So, I did replace the forward o2 sensor on the drivers side and have the same result.

http://www.rockauto.com/catalog/moreinfo.php?pk=1124632

Should I replace the other side then? Or should I replace the back sensor on the drivers side?

[Patrón]

Originally Posted by Haywood

Thanks. Can you elaborate on your reasoning?

a few posts already addressed it but i was basing it on:

// 9) 2B46 Combustion misfire with emissions deterioration cyl 5
// 10) 2B47 Combustion misfire with emissions deterioration cyl 6
// 11) 2B48 Combustion misfire with emissions deterioration cyl 7
// 12) 2B49 Combustion misfire with emissions deterioration cyl 8
// 13) 2B4E Combustion misfire with emissions deterioration several cyl
// 14) 275E Lambda control stop error bank 2

[pbonsalb]

Originally Posted by Haywood

Thanks, Mike.

So, I did replace the forward o2 sensor on the drivers side and have the same result.

http://www.rockauto.com/catalog/moreinfo.php?pk=1124632

Should I replace the other side then? Or should I replace the back sensor on the drivers side?

As car as I know rear 02 should have no effect on driveability. They are narrow band sensors just for emissions.

If you are sure you changed the correct bank -- and I don't know which is 1 and 2, I'd clear codes and also reset adaptions and try again.

[scrammer]

Originally Posted by Mike Benvo

Also just FYI:

VKAT = VOR (Before) Cat
NKAT = NACH (After) Cat

So the upstream sensors are fine, it's a precat sensor causing the issues.

Hope this helps, easy fix in this case.

If I was you, I would phone Mike give him my credit Card number in advance and ask for the details for the … "easy fix in this case" and then go driving!.

Cheers

[squartus]

When you removed the O2 sensors from the pipes did you unclip them from the car then unbolt them or did you unbolt them twisting the wire as it came loose?
Alot of times people will do the latter and damage the O2 sensors.

[Haywood]

Originally Posted by squartus

When you removed the O2 sensors from the pipes did you unclip them from the car then unbolt them or did you unbolt them twisting the wire as it came loose?
Alot of times people will do the latter and damage the O2 sensors.

Yes. I definitely unclip them and never twist them.

[JsL]

Just checking... Did you install O2 extenders on the xpipe? If so, the extenders go on the post cat sensor, not the one before.

[Haywood]

Originally Posted by JsL

Just checking... Did you install O2 extenders on the xpipe? If so, the extenders go on the post cat sensor, not the one before.

No extenders. Just a straight replacement.

[FogCityM3]

Had two O2 sensors go out on me within 5k miles. These things go out all the time.

[Haywood]

Originally Posted by FogCityM3

Had two O2 sensors go out on me within 5k miles. These things go out all the time.

Which ones? How did you know which ones to replace?

[FogCityM3]

It was the post cat O2 sensor both bank 1 (I still have my stock cats)... Mike Benvo (aka Mr. Troubleshooter) was the one who told me. Took to dealer and sure enough that's what it was, but made it sound like they did this massive diagnostic protocol (I don't know why because it was covered under warranty). Was a little ridiculous sounding.

Originally Posted by Haywood

Which ones? How did you know which ones to replace?

[Haywood]

Originally Posted by FogCityM3

It was the post cat O2 sensor both bank 1 (I still have my stock cats)... Mike Benvo (aka Mr. Troubleshooter) was the one who told me. Took to dealer and sure enough that's what it was, but made it sound like they did this massive diagnostic protocol (I don't know why because it was covered under warranty). Was a little ridiculous sounding.

Thanks. Sorry to sound stupid, but I want to make sure I understand this.

There are 2 sets on each side. The forward and the rear. Which one is post cat? I replaced the forward one on the driver's side.

[Sered]

You never replace just one O2 on these cars. The sensors aren't just used for AFR measurements, they are also used to measure EGTs. If one bank is reading significantly different values than the other (and it will if you just replace one), then you're going to have issues.

If you've got a BPM tune, then the secondary O2s won't need to be replaced, they're just there for emissions compliance and are disabled from the tune.

[Haywood]

Originally Posted by Sered

You never replace just one O2 on these cars. The sensors aren't just used for AFR measurements, they are also used to measure EGTs. If one bank is reading significantly different values than the other (and it will if you just replace one), then you're going to have issues.

If you've got a BPM tune, then the secondary O2s won't need to be replaced, they're just there for emissions compliance and are disabled from the tune.

Thanks. So, the secondary o2's are the rear ones?

Do you live in Melbourne? I went to Florida Tech. Have you been to Meg O'Malleys?