I just replaced both O2 sensors on my B16, since I've been trying to get it to pass emissions for a long time now, and they're about the only thing I haven't already replaced. I had the two O2 bungs welded in my DC 4-2-1 header and put in brand new universal, single wire NTK (OEM replacement) sensors.

The problem is, now it's idling at 1300 (idled at 700 before) and it's running worse than before. It also seems to be running a lot richer, because when I took it to DEQ, the hydrocarbons and CO2s were actually much higher.

I'm thinking that before I replaced the sensors, the ECU must have only been running in closed loop, whereas now that it sees two working sensors, it's running in open loop. I just don't know why it's not correctly adjusting the mixture? Any help with this is greatly appreciated!

 

Check your wires. Pin c16 is the primary o2 location on the ECU and c8 is secondary.
On the manifold itself, looking at front of engine with the stock exhaust manifold, primary 02 is closer to the timing belt and secondary is closer to battery side of engine.

 

Yeah, I should check the wiring at the ECU end. I did try switching the two wires at the O2 sensor ends though, and it didn't seem to make a difference...

 

i replaced both of mine and i have the same header and get this i still get a CEL, any ideas what to do now?,

B16a and o2 are a pita!

 

WTF, that's weird... I replaced my O2 sensor about a month ago and the car runs great now. However I only replaced the primary O2 sensor..

Do you have a tunable FPR? Anything else that would affect the fuel pressure or mixture modified?

 

No FPR. Like I said, I wonder if the ECU was in closed loop (factory settings) before and now with the new O2 sensors, it's in open loop? Maybe it's the timing??????

 

Did you reset the ECU? The computer wont clear the codes until you reset the ECU

 

Oh, yeah I did...I forgot to say that. I disconnected the negative battery terminal for about 20 min. Is that the correct way?

 

I just pull the hazard fuse for 10 seconds, also make sure that those wires are not crossed. Mine ran better with the codes, if I cleared the ECU it would run like poop until the CEL came on. After switching them it ran great. Reset the ECU everytime you try something new.

 

Hi T Rex
Apologies for breaking the thread but wanted to ask what part codes are the NTK ones? I tried geting some NTK direct from NGK UK but they couldn;t help me.

...are they plug and play ones or do you have to hardwire them in??

Thanks in advance
manf

 

That's ok...next time just send an instant message...just click on the IM bubble. I don't remember the part numbers, but I got them here: http://www.oxygensensors.com/

If you call (or email )them or NGK direct, they can tell you the part # for the single wire one.

 

up

 

i had the same problems as u
so i said **** it, and i got a zdyne
problem solved.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slowpokesi &raquo;</TD></TR><TR><TD CLASS="quote">i had the same problems as u
so i said **** it, and i got a zdyne
problem solved.</TD></TR></TABLE>

Was that for emissions reasons, or for performance? Can you tell me what you had them do and how much it cost?