S14 Hotshot header no 2nd o2 sensor

[jdm538]

i just bought a 3rd gen hotshot header off ebay and the guy said he welded closed the second o2 sensor bung will i be having any issues besides the engine check light?

[speedjay]

I'm running mine without the 2nd o2 and im not even getting a check engine light.

[theicecreamdan]

im rocking an s13 hotshot header on my s14... had to plug one EGR hole, and still need to re-angle the other EGR hole, and my second 02 sensor is just hanging under my car...
ghetto, but it runs fine

[rhino240sxse]

does it really matter if have any, or just one pluged on?

[sncs14]

if the guy just welded up the bung and you still want to use it just drill out the weld and run a tap through it

[Drunk Bastard]

I had the same EXACT problem. It doesnt matter that the o2 bung is welded, because it is too far forward anyways. if you want to run the 2nd o2 sensor then you will need to have a muffler shop weld ANOTHER bung, thats the CORRECT size, about 6-8" closer to the exit side of the header...otherwise you will throw a CEL

[Ranger_Man]

Mine is throwing a code and it runs fine.

From the 1995 FSM:

"The rear headed oxygen sensor is not directly used to control the engine system. It is used only for the on-board diagnosis of three way catalyst."

Interesting info though:

"The output voltage of the sensor, depending on its resistance is approximately 0 to 2.2v. The ECM supplies the sensor with approximately 2v and then measures the output voltage depending on its resistance."

That being said, if the CEL bothers you I can almost guarantee that you could buy a certain resistor at any Radio Shack, wire that sucker in and fool the ECM into not throwing a code. I, however, am no electrical genious, and the CEL doesn't bother me one bit.

[rhino240sxse]

Mine is throwing a code and it runs fine.

From the 1995 FSM:

"The rear headed oxygen sensor is not directly used to control the engine system. It is used only for the on-board diagnosis of three way catalyst."

Interesting info though:

"The output voltage of the sensor, depending on its resistance is approximately 0 to 2.2v. The ECM supplies the sensor with approximately 2v and then measures the output voltage depending on its resistance."

That being said, if the CEL bothers you I can almost guarantee that you could buy a certain resistor at any Radio Shack, wire that sucker in and fool the ECM into not throwing a code. I, however, am no electrical genious, and the CEL doesn't bother me one bit.



will that really work? wow i might try it... if any1 has done that resistor thing please let me know...

so the first or front o2 goes to the engine management then? if so i wonder if u can trick that too in gettin more power??? i wonder :jerkit:

[email protected] -email if any1 has done that

[Drunk Bastard]

no, you wont get anymore power by doin anything to the o2 sensors...short of changing them out for new ones. like it was said above the 2nd o2, the one that wont go into the header, is just there to make sure that the amount of stuff coming out of the cat ISN'T the same amount going in. your options for no CEL are: install the 2nd 02 and let your car run the way nissan designed it to or unplug the 2nd 02 and put a resistor in.....and if you dont care about CEL's, then just take the 2nd o2 sensor out, tape up the harness and call it a day. My CEL is permanently on, and my AIRBAG light flashes constantly.....you get used to it!

[projectRDM]

will that really work? wow i might try it... if any1 has done that resistor thing please let me know...

so the first or front o2 goes to the engine management then? if so i wonder if u can trick that too in gettin more power??? i wonder :jerkit:

[email protected] -email if any1 has done that

Think about that for a second. If you were to 'trick' the ECU into maybe leaning out the fuel curve, or dumping for fuel to compensate for an extra lean mixture, you still haven't actually altered the airflow.
Just like those intake resistor mods on Ebay, even if the ECU monitored and adjusted A/Fs from the intake air temp sensor (it doesn't, for the clueless people) you're still not benefiting anything. The ECU will dump more fuel to compensate for the increased airflow, but there isn't any actual airflow increase and therefore the car runs dead rich, loosing power.