86 Bronco II EEC Code 41 O2 Sensor?
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86 Bronco II EEC Code 41 O2 Sensor?
My 86 Bronco II with 2.9L has been running a little rough, bogging down and getting terrible gas mileage lately.
I pulled the codes and got:
33 - EGR valve opening not detected
and
41 - HEGO sensor circuit indicates lean
My plan is to change the EGR valve and possibley the oxygen sensor.
Does anyone know if code 41 is caused by a faulty O2 sensor or does something else cause the lean and the O2 sensor is just picking up on it.
How hard is it to change the O2 sensor and where is it?
Thanks
Pat
I pulled the codes and got:
33 - EGR valve opening not detected
and
41 - HEGO sensor circuit indicates lean
My plan is to change the EGR valve and possibley the oxygen sensor.
Does anyone know if code 41 is caused by a faulty O2 sensor or does something else cause the lean and the O2 sensor is just picking up on it.
How hard is it to change the O2 sensor and where is it?
Thanks
Pat
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Does anyone know if code 41 is caused by a faulty O2 sensor or does something else cause the lean and the O2 sensor is just picking up on it.
Also note that a 33 could have many possible causes. Was this 33 a KOEO code or a CM code? KOEO codes almost have to be electrical in nature so a KOEO 33 is not likely to be fixed by changing the valve itself. Most likely a problem in the PFE sensor circuuit.
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Both codes were continuous.
Pep Boys wanted to run the flow chart to troubleshoot further but they wanted a bunch of money to do it. More than the EGR valve and O2 sensor cost combined.
I decided to take my chances.
What are the symptoms of running lean? I just changed the plugs and they were covered in soot/carbon build up.
Pep Boys wanted to run the flow chart to troubleshoot further but they wanted a bunch of money to do it. More than the EGR valve and O2 sensor cost combined.
I decided to take my chances.
What are the symptoms of running lean? I just changed the plugs and they were covered in soot/carbon build up.
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If you have a Haynes/Chiltons, they usually have a color page that points common spark plug conditions and what they indicate. I think the same thing has been posted in a couple places on the internet (NGK I think was one of the sites with it). Soot/carbon buildup might indicate that it's running rich. If it is indeed running rich where the O2 sensor indicates lean, then there is likely a problem with the O2 sensor and/or circuit. Don't forget that a break in the circuit (like having a wire lay across an exhaust manifold and burn through) also triggers codes.
I wouldn't put much into the EGR valve until I had at least verified that the vacuum lines were all good and the wiring from the PFE to the computer was good.
I wouldn't put much into the EGR valve until I had at least verified that the vacuum lines were all good and the wiring from the PFE to the computer was good.
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Pressure Feedback EGR sensor. Used to monitor operation of the EGR system. When a CM 33 is set, it is because this sensor's signal is out of range. The sensor attaches to the throttle body and has a vacuum line going to the EGR valve and an electrical connector to talk to the computer.
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