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2000 323ci E46 White Convertible
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56 Posts
Last night I replaced the valve cover gasket and grommets. I was able to find the majority of the 10 mm inside-threaded bolts, but am missing two... when I took them off, two of them were a different size. May swing by parts store to get the rest of them and an engine cleaner.....
 

· Registered
2000 323ci E46 White Convertible
Joined
·
56 Posts
Battling random P0171/0174 codes and a decrease in fuel mileage. LTFTs were regularly double-digits+. Did TB gasket, upper/lower intakes hoses, and rebuilt DISA valve with the G.A.S. kit and new o-ring. The o-ring was the only thing that visually looked suspect, as it was flat and hardened, but not cracked.

That cured the CEL problem, as the codes have not returned. Mileage was still a problem. At 145k miles, I thought I would just do everything; plugs, coils, AFM, vacuum lines, intake gasket, etc. But I wanted to understand more what was actually causing the problem. I read all the guides on fuel trims, and thought I’d start with the AFM. FCP delivered it Thursday evening and I popped it in and went for a short drive (under 10 miles). No change to LTFTs. So I kept reading and thought it might be a fuel pressure issue, and planned to rent a gauge to check this weekend.

As I had a 150-mile round trip for work on Friday, I used the OBD Fusion app to monitor fuel trims during the drive. Several miles in, still no change. I was convinced I was going to need plugs, coils, and a new pump for sure.

Then I got some movement. +11.7 became +10.2, then +9.6, then +7.8. By the time I returned home my LTFTs were +/- 1.6! My mileage on the drive was noticeably improved as well, climbing back over 21 mpg combined.

I will get around to the rest of the list, but for now I’m ecstatic to have the car performing as it should! ‘01 330Ci
I think I read somewhere in the manual that it takes a certain amount of miles or trips for the car to turn of lights or accept the new readings. Like an average over the tank capacity/miles driven. The number 4 sticks in my head for some reason. Did you just happen to randomly "pick" the MAF/AFM to replace or did you suspect it somehow? I am suspecting mine, and will change it if my current replacements don't work, but I wasn't sure if there was a way to test it. I know!! I will search in the forums!
 
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