chadk

I had to replace the drivers side O2 sensor again today. Last time I did it was in January of this year. Both sensors had a fair a amount of black soot. I replaced the plugs a few weeks ago and they all looked good. Fuel pressure is at 43PSI. What do you think can be the problem?

antfarmer2

how are your injectors? how long does your fuel pressure hold after shuting down? does your vacumme line on your fpr smell of gas? could your cat be pluged up a bit? do you drive like a old lady?

RUU

Coolant in the exhaust via a head gasket leak will wreak an O2 sensor in short order.

chadk

These are all good suggestions.
The injectors are probably wore out. The fuel pressure held well for 5 minutes. That's when i disconnect the guage. Should I have held it on longer? The cat is probalbly full of that crap. I'm the 7th owner.
I don't think it's anitfreeze. I Don't add any.
No vac leaks that I can see.

antfarmer2

mine is all factory and will hold all night. replacement pumps not so much. smack good around on your cat and listen for rattles. then have someone start it and see what comes out the back.

desertmike1

Why? what are the symptoms? Do you use "Any" Silicone adhesives, or Lubricants any where near the intake system? O2 sensors are fairly robust, and don't just go bad...

chadk

Symptom - "Check Engine Soon" light came on when going into closed loop. H44 was the code. Same thing that happened last January. Upon closer inspection of the O2 sensor it was covered in black soot. I replaced sensor and troubles went away. I have read that O2 sensors dont work well in that type of condition.
I do not use any silicone or anything else to that matter. Not even fuel injector cleaner.

I am leaning on vacuum leak or faulty injectors. Probably way to much fuel causing black soot.

antfarmer2

get a cheap cigar and blow smoke into the hose off your brake booster into the engine and see where it comes out.

desertmike1

OK, H44 is an O2 sensor left bank, sensing a lean condition.. too much Oxygen in the Exhaust. The PCM is trying to adjust for this by increasing the fuel..

I just had this problem on an 1998 Malibu, it was a P0171. turned out to be a bad Vacuum Cap on the intake manifold..

WW7

It could be as simple as a piece of crap Chinese made O2 sensor that just went bad...With most of our parts coming out of China now, I'm seeing more and more parts that are bad right out of the box , or that go bad in a short time ..Now days if something doesn't work when I replace a part, a bad part is the first thing I suspect.....WW.
.
.
.