Passing Smog FaQ

[lodownlv]

If your o2 sensor is bad it may or may not trip a check engine code if your check eng light is on then its a 100% fail in most states. A bad o2 sensor wouldn't nesassarly make u fail smog as I know many people with no o2 sensors at all. Take both o2 sensors out and clean them with carb cleaner and wipe them dry and reinstall. Now for the swirl control valve. This is a part that controles air intake in the engine giving your engine proper combustion and mostly just saves fuel. It is located in the upper section of the intake manifold on pas side, on rear of the engine. This is big tubular thing that connects with 4 diffrent pipes to the head :-) (This is called a plenum). The swirl control unit looks like a canister with a vacume line connected to it. Check to see if the valve opens when u start your ride. Then pull the vacume line off of it. Did it close? If not u got a bad swirl control valve. This is a dealer only part that costs 80 bux. Its realy better to take the whole unit off and take the flaps out of the intake plenum. And its a 4hp gain! (Best For Turbo Aplications) Also runnin platinum plugs increase combustion giving u less o2 readings I recommend botch platnum. Finaly clean your throtle body with some carb cleaner too. Remove pcv valve located on the front of the valve cover and spray in the hose that connects to the throtle body. If you dont pass smog then u got some serious internal issues. (Bad Rings, Bad Valve's, Bad Fuel Injector,) Would be other places to look.
Peace

[mrflip69]

S13 has one o2 sensor, S14 has 2?

[lodownlv]

i got a s13 it has 2. im not sure about the s14 im stumped. O2 sensor Suck.

[mrflip69]

Where's the second one on the S13? I thought the only one was by the exhaust manifold/heat shield? BTW mine is SOHC if that makes a diff...

[lodownlv]

I got a DOHC I dont know i must be high again :-)

[nissanfanatic]

My S13 is a DOHC and there is only one on the header. I've heard people say that is odd and that thiers has two. I guess the Nissan people just got high and couldn't remeber if they put one or two on. lol

[mrflip69]

Yeah... I'm pretty sure that only S14+ have 2 o2 sensors... well whatever

[alkemyst]

I think OBDII dictated more than 1 O2 sensor. You need 1 prior to any cat and 1 after any cat for OBDII compliance.

[mrflip69]

Sounds right... the second o2 sensor should be in the dummy cat of the S14s

[lodownlv]

I have 2 o2 sensors because of an upgrade for a air fuel ratio gauge after the high flow cat.

[zdude]

where in the hell are the o2 sensors on an s13, i cant friggin find em, and ive been asking for a while

[nissanfanatic]

One is on your exhaust manifold right at the bottom before it meets the connecting pipe to the cat. The manifold is a two piece. The factory heat shield may be in the way but you should at least be able to find a wire running to the manifold from the engine bay.

[lodownlv]

its not to hard to inspect where it is it dude one wire o2 sensor

[zdude]

wow, i feel like a retard, i found it, but prolly before you guys posted the answer, canisay helped me out. its right out in the open too, thanks anyway guys

[lodownlv]

u must be high.
LOL