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Discussion Starter · #1 ·
I bought my 99 328i a month ago. When I purchased her the check engine light was on. I ran the codes, and found out she was running lean in banks 1 and 2 and had a misfire. I replaced the valve gasket which was hard plastic, changed the spark plugs, replaced the intake boot, cleaned the ICV and DISA. I then replaced the pre-cat O2 sensors. I ran her for a few miles and had my buddy reset the codes. I then drove her home, and the light came back on grrr. I really haven't driven that much in the past few days since I changed out the O2 sensors. Then tonight I drive to my buddy's place and hang out for a few, and then I get back in my car and the check engine light is now off. I drove her for about 20 miles, stopped and got some gas, and came home and the light is still off. Did it just take a while for the O2 sensors to work, or perhaps the computer to figure out the parts have changed and to compensate for them? Any help would be appreciated.
 

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Does your buddy's obd2 scanner have a live data option where it outputs the data from the ecu while the car is running? If so can you make a video focusing on bank1 and bank2 short-term fuel trim (STFT) and long-term fuel trim (LTFT). At least this way I can see how much fuel the ecu is adding that would cause a lean condition. Also if you do have pending and store codes, please list them in order from the first that is listed by the scanner. Thanks
 

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Discussion Starter · #4 ·
Ok, the light came back on after a day's worth of driving. My codes are P1189, P1188, P0170, P0173. Since I have aready changed the plugs, valve gasket, intake boot, pred-cat O2 sensors, and cleaned out both the ICV and DISA, I can only assume the oil separator hose has a leak somewhere and it needs to be changed. If you guys can think of anything else let me know.
 

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Ok, the light came back on after a day's worth of driving. My codes are P1189, P1188, P0170, P0173. Since I have aready changed the plugs, valve gasket, intake boot, pred-cat O2 sensors, and cleaned out both the ICV and DISA, I can only assume the oil separator hose has a leak somewhere and it needs to be changed. If you guys can think of anything else let me know.
Interesting. I can't say for sure that the oil sep is the culprit, certainly could be, but those are pretty generic codes. The BEST thing to do, is a smoke test. It'll show you the leaks you have and make it an easy diagnosis.

All that other stuff may not have fixed the issue, but it was all maintenance stuff you would have had to do eventually so no harm no foul. :thumbup:
 
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