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Emission Advice

1241 Views 8 Replies 4 Participants Last post by  RobertA
Need your help again guys......what else is new? So, I took my Z to a NJ state inspection facility. Of course it fails. They did a primary Emission test. It passed the idle mode but failed the High Idle Mode. The CO% reading was 2.99 and the standard is 1.20. I have driven the car less than 2K miles this past year so my first thought was that this may be the cause of this but I am not sure. Anyone have any thoughts? I have to bring the car to a certified shop (as per the NJ facility paperwork) to get "repaired" but I have no idea what I am looking to repair? The car is a 93 2+2, everything is stock.

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Hm. Do you know when your O2 sensors were replaced last? When failed emission is mentioned O2 sensors always comes to mind first. Have you tried the O2 sensor diagnosis via the ecu?

Also any codes being thrown?

Vacuum problems can be common causes of emission failure as well.
I am not sure when the O2 sensors were replaced. I got the car a little over a year ago. I can't pull codes from the ecu because the dial on the ecu is pushed in. I purchased a conzult and can't get it to work (i think it is an XP issue, i have two laptops and neither is running xp).
I am a mess dude. I have limited knowledge of this stuff as it is.
New O2 sensors fixed my emissions problem a few years ago and it is very common although not the only possibility of course. With your Z being stock, that's a good bet.
Thanks guys. I ordered two direct fit O2 sensors. How hard is it to swap out? I assume that the car needs to be lifted so I am going to have to take to a shop to do it for me.
Its easier from above than below. I have a pit and the same is true. And it's pretty much a bitch of a job. One of the more annoying things you can do on your Z. But if you have the right tools and ambition, I think you should try and tackle it yourself.

I did both of mine from the top.

You need a crows foot, like two extensions, and a swivel (not necessary but makes it easier)

Passenger side is easy, just remove the battery for a good shot. The drivers side is more of a pain.
In conjunction with changing the O2 sensors, i would put some miles on it.. make sure everything is good and hot when you go for the inspection..
Thanks. I was thinking about this at work today and I probably should have taken the car on the highway and opened her up for a while before getting the inspection. I drove for about 25 minutes on roads and side streets.
20 minutes on the highway at 3000 RPM or more should suffice. Drive in 4th gear if you need to avoid speeding.
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