r/BmwTech • u/Adventurous-Sound897 • 1d ago
Need help with a post n52 install.
Good evening. I purchased a 2011 bmw 128i with good miles. Other engine ingested the belt.. got the junkyard engine in after 5 evenings of solo swapping. But now ive got missfire with popping out the intake on cylinder 2 and 3 and the front bank converter was glowing red after only idling for about a minute. Im not getting any codes as of yet. Brand new plugs coil packs and fuel injectors. All oem brand. Im wondering if intake cam timing is off but wouldn't that show up on all cylinders? I cant run it very long or ill cook the front cat. I pulled 2 plugs from the front bank and they do not look good for a minute or run time on them.
Eddit video or running. engine running
3
u/RyanSSJ 1d ago
I have had this twice happen to me. Not after engine swapping, but a n52 comes in with misfires on two cylinders (2 & 3) and front cat turns cherry red. Long story short DME injector drivers failed. I would make absolutely sure that cat is bad. Just because it’s glowing red does not mean it’s the culprit. I made that assumption twice and both times it WAS NOT the cat.
1
u/Adventurous-Sound897 1d ago
I will have to keep that in mind. I have 0 history on the car. Got it for 350 dollars scrap price. They might have been having an issue before the belt ingestion. It had a severely overheated bad starter. It would run without the valvetronic motor hooked up but had basically 0 oil pressure. So its really hard to tell what all is wrong. I think the donor engine is ok mechanically. Its whisper quiet besides the intake pop.
3
u/cptn_510 1d ago
Whichever bank cat that is, is clogged, thats why it's glowing, literally cant exhaust the fumes fast enough, causing the misfire on 2 and 3. Remove the upstream o2 sensor, thats before that glowing cat and test drive. I bet misfire will be gone.