[Bims328i]

I have the reoccurring 29F5 code and am waiting for an opening to replace one if not both of my manifold converters. Missed the window for warranty so I'm going to have to do this myself.

I really can't figure out WHY it is the bank 2 cat (rear manifold) but it apparently needs to be replaced. Going to try and do that while tackling the oil pan gasket and motor mounts.

Inspecting the used replacements, the honeycomb looks ok. I had a weird metallic sound for a while when starting up the car but has since gone away. Will have to wait to see but I suspect it was a piece of the honeycomb that was maybe broken off and jumping around until exhaust pressure was established. Just a theory.

Maybe I will procure a borescope beforehand so I can inspect the old manifold better. It's tricky fishing a dental mirror down into the manifold to check honeycomb condition.

[Diyengineer]

BIMS,

Fire your car up and use a FLIR. You can rent them from most Home Depot’s or Lowes if you don’t want to buy one. Shouldn’t be much of a temp drop through it. I’ve heard if it’s more than 100f difference between inlet outlet it’s bad.

Originally Posted by Bims328i

I have the reoccurring 29F5 code and am waiting for an opening to replace one if not both of my manifold converters. Missed the window for warranty so I'm going to have to do this myself.

I really can't figure out WHY it is the bank 2 cat (rear manifold) but it apparently needs to be replaced. Going to try and do that while tackling the oil pan gasket and motor mounts.

Inspecting the used replacements, the honeycomb looks ok. I had a weird metallic sound for a while when starting up the car but has since gone away. Will have to wait to see but I suspect it was a piece of the honeycomb that was maybe broken off and jumping around until exhaust pressure was established. Just a theory.

Maybe I will procure a borescope beforehand so I can inspect the old manifold better. It's tricky fishing a dental mirror down into the manifold to check honeycomb condition.

[Bims328i]

Originally Posted by Diyengineer

BIMS,

Fire your car up and use a FLIR. You can rent them from most Home Depot’s or Lowes if you don’t want to buy one. Shouldn’t be much of a temp drop through it. I’ve heard if it’s more than 100f difference between inlet outlet it’s bad.

I don't have one atm but I'll look into it. In my case this code just keeps coming back. I have a replacement sitting behind me right now.

It must be something with that cat because the OBD just keeps flagging it as a problem.

[Diyengineer]

Originally Posted by Bims328i

I don't have one atm but I'll look into it. In my case this code just keeps coming back. I have a replacement sitting behind me right now.

It must be something with that cat because the OBD just keeps flagging it as a problem.

You planning on trying to remove both from the top? I saw a video about removing the front one from above, didn’t see if it was possible with the other rear one.

[Bims328i]

Originally Posted by Diyengineer

You planning on trying to remove both from the top? I saw a video about removing the front one from above, didn’t see if it was possible with the other rear one.

I was planning on removing them while I had the subframe dropped to address the oil pan gasket. I have seen some info about extracting them from above but have not fully considered it. I suppose I will see if raising the motor via support brace will do the trick.

If anything, may need to remove the coolant expansion tank to extract the two manifolds. Just trying to think ahead. Cheers!

[Diyengineer]

Just closing this out. Wasn’t the cats (faulty error). Two ground straps and a starter was the fix. Thanks for the help, more problems to come.