I have had my OBX headers and Y pipe for some time and had to replace alternator so decided to go ahead and attack the install of the headers and Y pipe at the same time.

What I didn't see in my research was about the 2 after cat 02 sensors. What do I do with them so that I don't get a check engine light. Do I need to buy some 02 simulators or something to fool the computer into thinking they are there or a really long wiring extension to put them after that 3rd remaining cat or just what do I need to do about that.

Our emissions testing only consist of plugging into the ALDL plug under the dash so as long as i don't have codes, I am good to go.

Thanks,
Brian

 

O2 simulators.

 

first off...what year maxi? cali or fed spec?

depending on the spec, you have either 3 or 2 oxygen sensors on the stock y-pipe. The aftermarket y-pipe shd have openings for the oxygen sensors. No need for simulators.

PM IIYAK and ask him what he did. Or SEARCH, he has already posted what to do.

I recommend only installin the radiator side headers. its much easier than the firewall side header.

 

Almost forgot......there is a HOW-to tutorial for installing the warpspeed y-pipe. Its a thread in the main page of the 4th gen forum.

 

As far as I know mine is a Federal Emission car but the thing has 4 o2 sensors. 2 in front of the cats in the manifolds that the computer uses to adjust the fuel mixture and 1 on the output of each front cat giving a total of 4. I put the 2 manifold sensors in the 2 available ports on the new exhaust and now I have 2 aft cat o2's hanging out in the air at the moment. If I need o2 sims, where do I get them?

 

If you have 4 O2's, you're a Cali spec. car.

The easy way to confirm this is to look at the number of censors at the front of the front valve cover just behind the radiator. If you see 4, you are Cali. If you see 2, you are fed.

If you are fed, you don't need an O2 simulator. You only need one if you are Cali.

I was cali but converted my car to fed (headers and y-pipe) and have an O2 simulator to take care of the other two O2's (which are ziptied above the headlights on the underside of the radiator support).

 

Then it must be a cali spec car but I am not in cali. I am in NC and bought the car from original owner in PA and according to car fax it was never registered in CA. I have 3 02 connections by that front valve cover 2 4 wire 02s rolled up now and the 2 front 02's are 3 wire 02s. the other 02 connection is by the rear valve cover in the front for the back exhaust manifold. From what I can find on 02 sims, I still have to have those rear 02's in the exhaust somewhere to not throw a heating element code and then possibly the sim for the signal wire for the computer to be happy that it has no front cats. Kinda wished now I hadn't screwed with the thing.

 

You are Cali.

The reason you are Cali and on the east coast is because your car came in through a California port most likely. No biggie.

 

For now, I believe, I will get some M18X1.5 stainless nuts and weld in the Y pipe and mount those 2 o2 sensors and see what happens as far as codes. If I get a code for cat efficiency then I guess it will be o2 sim time and i will have to post as to which wire on those 4 wire o2's is the signal wire for the computer that needs the SIM attached.

 

interesting thread;

will these 02 simms work on our car?

http://www.o2simulator.com/index.php...ndex&cPath=1_9

 

Unfortunately they aren't selling anything anymmore. Here is a line from their home page.

Web store is currently disabled. We have accumulated number of unanswered emails and we would like to respond to everybody before resuming sale. Sorry for inconvinience.

I tried to order but I couldn't pay. I ended up making my own which I just ruined by hooking up incorrectly. I'll make my next one a dual output using a 556 chipe instead of a 555.

 

I looked at the emissions sticker under the hood and it is definitely a california emissions car which was mentioned earlier. I put the 2 after cat 02's just in the Y pipe where they would be convenient to get to and have about 50 miles on the setup with about 4 engine restarts and so far no codes. So I might get lucky and not have to mess with the thing but if I do, I will have to search for someone that is currently selling o2 sims. If I get a code, i will update this post stating that i did get a code but so far so good. Can't say that I notice that much difference in the performance for all the work that it took to put everything on. the fit of the OBX headers and exhaust was spot on though. Just nothing front wheel drive is fun to work on.

 

we're in the same boat. I'm cali as well amd been searching for a write up or info on what is needed for this installation. :subscribed:

 

Here is the gist of the install:

1) Remove air intake system
2) Remove EGR system from rear header (14mm nut I believe - tough to get to)
3) Remove radiator in order to have room to take the front header off
4) Remove O2's from header/y-pipe
5) Remove Y-Pipe
6) Take off the heat shields covering headers (3 or 4 8mm bolts each)
7) Remove cross member to be able to get the headers out
8) Remove headers (6 12mm nuts I believe)
9) Do reverse to get new headers/y-pipe in there

*Note*

Use OEM gaskets and anti-seize


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I did this install like 2 years ago, so that's from memory. I may have missed steps, etc.