So I installed a new fuel filter and a dual output O2 sim this weekend. I now have an erratic idle and hesitation when I accelerate. I have searched but not found anybody who could attribute this problem to a newly installed fuel filter or O2 sim. I have not cleared the ecu yet so I am going to try that but I don't believe it will do anything. I installed a New MAF sensor 2 weeks ago and it has been functioning perfectly so I think I can rule that out. Just to make sure I spliced into the correct secondary O2 sensor on the front bank could someone please tell me where it is located (I spliced into the one near the firewall on the passenger side). when I installed the new fuel filter I pushed it a little hard once I got it into the hole. I didn't mean too but it was like the springs got stuck and then unstuck so while I was pushing it just seemed to compress and I hit the bottom of the housing kind of hard. This maybe of done something but I am not sure.

 

Ok so I was just looking on the FSM and it says that the O2 sensor plug located on the passenger side firewall is for Front Bank 1. So I am assuming that I tapped into the wrong location. Now I believe the other O2 sensor I tapped into (Dual output O2 sim) was the rear bank 1 sensor. I believe that this is correct. So there are 3 O2 sensors connectors in the front of the engine (going from left to right): Heated O2 sensor 1 (front Bank 2), Heated O2 sensor 2 (rear bank 2), and Heated O2 sensor (rear bank 1). Which 2 O2 sensors am I suppose to be tapping into.

 

Ok so after about 2 hours of research I found (stumbling) that only the Secondairy O2 sims are suppose to be replaced. that is the 2nd and third sensors on the front of the car starting from the left. (HO2s2-B2 and HO2s2-B1) Please correct me if I am wrong.

 

ure supposed to use simulators on the 2 o2 sensors only after the pre cat (mainafold. The ones downstream to simulate a working catalitic converter so you do not get a MIL light.

 

I have a y-pipe and I am confused about just which o2 sensors to replace. according to the FSM would these be labeled as the "rear bank 1 and rear bank 2" sensors?

 

On 2000 Cali spec the rear sensors have gray wire (bank 1) and red wire (bank 2) respectively. If you spliced yellow or blue, you got the wrong sensors. Those are the front one i.e. S1; you want to splice the S2 sensors.

- Vikas

 

Why are you using o2 sims? Did you remove the pre cats on a cali spec vehicle?
Other then that, there is no reason to use an o2 sim.
Please explain why you are using o2 sims. We may be able to help you better.

 

I have a warpspeed y-pipe on my cali-spec 2001 maxima

 

I thought the sims were only for headers throwing a code? Why does a aftermarket y-pipe throw a code?

 

My rear O2 sensors have been intermittent ever since I got the y-pipe. They lasted for the 1st year and then they started giving me problems. Every year I clear the codes and try tgo drive around 250 miles before I go get it inspected. Then a month later the codes come back. So instead I am eleminating the problem.

 

Did you ever try buying a new sensor and replacing the ones that seem broken?

 

I have bought both new sensors in the past and the problem keeps returning. I did resolder everything on the primary O2 sensor last night and all is well. I now have only one of the secondaries being fed by the O2 sim. We will see if I need to go ahead and install the second output of the O2 sim but I will wait till I get another code thrown. The car is running like a champ. All it took was a new MAF, new fuel filter, and installing the O2 sim. I will do seafoam and oil change next.

 

^^^ i kind if have the same problem once i installed my 02 sim i have a hesistation also,but i didn't replace my maf...between 1500 and 2500rpms my car has a lost of power under partial throttle... but full throttle no problems idle is okay...happen usually when driving at a steady speed...My car is an auto sometimes there's delayed shifts... plz don't tell me its my tranny and i have no codes at all...or tps

 

Damnit... My check Engine light came on and I am sure it is for the other O2 sensor that I was to lazy to simulate after fixing the other O2 sensor back. I will simulate that tonight and see what happens. I just hope its not one of the front O2 sensors. I will take it to autozone and have them tell me.

 

Did you ever find what was wrong? I have the same issue?

 

Yep. I had to properly add the O2 simulators. I just remember that you do NOT splice into the O2 sensor near the firewall (its a primary) or the one connected to the front header just under where you add oil during an oil change. That should leave just 2 O2 sensors remaining which are both secondary and only needed For emissions which you can cheat and use the Simulators. MAF sensors is the number one culprit for rough idle and car just running rough. If you car is in limp mode thats is probably the reason.