I used my scanner today and I am pulling two DTC codes(1133 & 1155). I believe they are for MAnagement Air Fuel control. Can some one tell me what might be the cause of this. I just put headers on 3 months ago with no problems til now. I have stock O2's up front and sims in the rear.

Mods are as follows.
2001 A4 Z28
Hooker LT's
Hooker off road Y-Pipe
NO Cats!!
SLP Loudmouth
all the regular SLP bolt-ons.
Hypertech ( not power tuned)

Thanks in advanced.

 

Are you sure the codes weren't P1133 (insufficient switching, Bank 1, sensor 1) and P1153 (insufficient switrching Bank 2, sensor 1). Might be a problem with your O2 sensor extensions, if you installed any. Or possibly contaminated sensors.

 

You are correct on the code numbers. Should I change out the extensions or the O2 sensors or both. I have O2 sims on the back. Do they have anything to do with it?
Thanks

 

Nothing to do with the post-cat sensors... "Sensor 1" means the pre-cat sensor on each side.

For some reason your O2 sensors are very slow in responding to the PCM's changes in the A/F ratio. Could be a problem with them not running hot enough, due to problems with the extensions, or the sensors may have been damaged. Have you run any "leaded" fuel recently? Did you do any work on the intake using any products containing silicon?

 

No leaded fuel has been run. No work on the intake at all. I guess it could be a bad sensor(s). I reset the computer and it pulled up 1133 on one ocassion then 1153 on another then both the last time. I reset it after each time and its usually after a whole day of running it before it comes on.
Thanks

 

Did you ever find the problem? I have the exact two codes now. I just installed MAC midlengths, I have a PCM tune from www.madz28.com also.

Dan

 

No I haven't yet. I reset the pcm using a scanner. Now after a little bit of driving I get only one code or the other. I still have my old 02's from when I did the header install. I may try to swap them out to see if it might be a bad 02 sensor. I may swap out the extensions as well being I have a spare set sitting around.
I'll let ya know what I find.