Very rough idle

coleybmw335 · 05-29-2020, 07:33 AM

Hi all,

I've got a rough idle on my n54 engine after downpipes install. Using INPA my o2 sensors post cat are reading around 0.77V but they go down to 0.08 for a second every now & then on both sides post cats.

Would this mean they are both bad sensors?

Both pre cats stay around 2.00v & go up when rev the engine & don't go below 1.92v.

No fault codes

Thanks

Bimmer_Bro · 05-29-2020, 10:09 AM

Sounds like you plugged the 02 sensors in backwards when installing the downpipes. Common mistake. Reverse the 02 sensors and see if your problem clears up.

05-29-2020, 07:33 AM	#1
coleybmw335 Private 11 Rep 82 Posts Drives: 2009 E92 335I DCT Join Date: Feb 2018 Location: Derby, England iTrader: (0)	Very rough idle Hi all, I've got a rough idle on my n54 engine after downpipes install. Using INPA my o2 sensors post cat are reading around 0.77V but they go down to 0.08 for a second every now & then on both sides post cats. Would this mean they are both bad sensors? Both pre cats stay around 2.00v & go up when rev the engine & don't go below 1.92v. No fault codes Thanks Last edited by coleybmw335; 05-29-2020 at 07:47 AM..
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05-29-2020, 10:09 AM	#2
Bimmer_Bro Captain 394 Rep 972 Posts Drives: 2010 BMW 335xi LCI Join Date: Dec 2019 Location: Calgary Alberta Canada iTrader: (0)	Sounds like you plugged the 02 sensors in backwards when installing the downpipes. Common mistake. Reverse the 02 sensors and see if your problem clears up. __________________ Instagram : @Bimmer_bro
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