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Discussion Starter · #1 ·
Hey Guys! So i recently purchased a 04 325i 4d E46 and i love it always wanted to join the Bimmer Family. However i have a small issue...

When I bought the car it had cracked intake boots(replaced those w/oem) cracked manifold (replacedw/oem) Blown Disa Valve (replaced w/oem) and the ccv hose to the dip stick was broken (replaced). The OBD2 came back with 13 codes at the time which were mostly caused by the vaccum leaks and some bad coils and some other things but everything has been fixed.
After clearing the codes and driving (just lite driving no hard accelerations or anything) for a while the CEL came back on and was throwing lean codes for bank one and two but the car ran fine no weird noises or shakes or anything. I checked all my hoses and connections and all was good so i cleared the codes and went for another drive. This time however I went for a pull and floored it and right around the 4000rpm mark the rpms dropped the petal had no power and the eml,abs, and brake light came on (no cel) and the car was idling bad once i stopped. After turning the car off the back on everything was normal no dash lights no rough idle. After i got home i checked the obd2 and there was no codes. Eventually after driving maybe 35 miles i got the cel and those same two codes for bank 1&2 too lean. I checked a few post and they said if it wasn’t vacuum it could be my cats being clogged and how to check by removing the pre cat o2 sensors which i did and what do you know no power loss or lights if i floor the pedal.
A few days ago I decided to go check the cats and broke all four or the rusted exhaust bolts however the cats didnt look clogged (i dont thin you would be able to tell from the exit side of the cat if it was clogged anyway).
Today i drilled the studs out and put non-foulers on the post cat 02s because read the the non-foulers can be used to keep the cel off if the cats are bad or if your hollowing out your cats or getting headers without a o2 delete you can use them to avoid cel. I hadn’t realized it until now but ive been driving very aggressively with the exhaust disconnect from the cats and the post 02 sensors out and the car never had that issue with the rough idle dead pedal and eml,abs and break light until now after putting the exhaust back in today with the o2s and non-fowlers; whenever i go for a hard acceleration the lights come back on and the pedal goes dead and it idles rough and then everything goes back to normal after i turn the car off then back on. Never got cel
Do i need to replace the cats?
Vanos?
Could it be a fuel thing? Im at a complete stop with my build and with the computer not throwing any codes im not sure what to do.
P.S sorry if this has been discussed. Ive read alot of posts with similar issues but the fix was something i had already done i.e : vacuum leaks and whatnot.
 

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No, the cats are likely ok. The intake needs to be professionally smoke tested to find all of the leaks. You need to get BMW Software to read all of the codes. The car is a rolling computer and you need the right software to scan all of the computers. Search this forum for threads in diagnostic software in which Balidawg has commented. He’s the software guru. Btw, when those lights came in when you accelerated you have what’s called the “trifecta”. The car went into limp mode. It does that you prevent damage to the engine and/or the automatic transmission.
 

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E30M3 Race F10 535 R1150Rt M Coupe
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Agree 101% with MM.
Do cats clog? Yes. Generally the exception.

More likely you have a vacuum leak: false air NOT being measured by the AMM (Air Mass Meter) and the DME is compensating.
Sounds like you took the hard road by reading generalities on the internet?

The 3 C's: Complaint, Cause, Correction. Focus on the last two and your knuckles will appreciate it.
 

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Discussion Starter · #4 ·
Ok thanks guys ill get a smoke tester today and smoke test the intake manifold. And yes definitely the hard road Mr. M
 
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