SMed08

Hi guys,

UK E55 owner here, recently bought PB5 long tube headers. As these were built for LHD, and I'm not aware of any long tube headers built for RHD cars, these needed quite a bit of fabrication to work. 3 of the drivers side runners required re-fabrication to fit, 2 of which were quite extensive. But that's all done now, and headers are, leak free and mostly interference free.

My main issue now is that it's running absolutely stinking pig rich. I expected it to smell more as the cats are now gone, but this is far beyond that. It smokes a lot, idle is rough and MPG has dropped significantly (about a third less).

My exhaust guy extended the primary and secondary O2 sensors and my tuner (DTK) disabled the secondary O2 sensors. Both primaries and secondaries are instream. And it's been experiencing the above symptoms. When on the throttle, it rips like a motherfxxxxer.

My question is, what is the best way to deal with the O2 sensors?

I've heard, it's better to pull the OEM O2 sensor harness, and unclip it as it should "stretch" and reach the new sensor bungs without having to re-wire.

Anyone else experience these symptoms when extending the O2 harness?

Star shows one bank works, and the other keeps cutting in and out. Would this cause these symptoms?

Thanks for any advice/experience with this. I've emailed the owner of PB5 2 days ago, but no response yet.

hachiroku

how did he extend the sensors? you should never solder the wires, and you should only crimp. ideally you should just buy extensions as i have for my E63's rears. it sounds like your O2 sensors are pushing out false readings.

SMed08

So just found out they were soldered. Great.

Already sourced OEM harnesses, going on today. Secondaries will be unplugged and blanked off. Hopefully this sorts it. Learned the hard way.

AMG_Adon

having the same problem my friend mine were soldered as well

AMG_Adon

where did you buy your extensions if u dont mind me asking im having the same problem

tw2

Just wondering, why is this?

SMed08

So replaced both the primary O2 sensors, with brand new longer harnesses. Secondaries are now blanked and tied away. Initially made no difference, cleared the codes and now runs perfectly.

My mechanic had some laying around the shop on the day, which is good news for me.

Expensive mistake to learn from, but glad to finally have it running well.

hachiroku

glad you were able to sort that out! O2 sensors are very touchy in regards to modification of wiring.