I took the ZX in for an emissions test this week and it failed. It was way above the limit on hydrocarbons at idle and the technician determined that the catalytic converter is bad. I took it off today to take a look, and it doesn't look like any catalytic converter I've seen before. Where is there is usually a honeycomb like structure inside, this one looks to be completely empty, as if it was gutted, yet it doesn't look damaged inside. Is this normal for a catalytic converter on a car this age? What I don't understand is how he determined the catalytic converter was bad without looking at it. Isn't the catalyst supposed to cut NOx emissions, which my car passed? Also, what could be causing all the unburned fuel at idle? Anyways, I attached the report from the emissions test and pictures of the inside of the catalyst. Let me know what you guys think.

 

It could be the PO gutted your cat. Usually as the converter ages, the honeycomb breaks down, but it doesn't leave behind a completely empty shell.

 

dude, save it, then after it passes toss it back on..

 

dudes some one tooked your platnums

 

Hey man, you did pretty good for having a gutted cat. I say do what I did. And what Shady has told me. Unplug the #5 injector, retard your timing, and raise your idle. I didn't retard my timing. But I did the other 2 things mentioned. And I passed almost better than a new car. And I burn and leak oil. And have bad rings. You should pass with that gutted cat. Because usually the cat prevents Carbon Monoxide. Which your readings are good. So try that, and see what happens. Good luck.

 

HOw does unplugging your number 5 and raising idle help you pass?? or is this a joke...

 

Clean flowing injectors, a good cat, and low timing are the best ways to pass emissions.

Unplugging a fuel injector reduces the amount of fuel going into the engine, thus reducing the emissions coming out of the engine (doesn't always work, but can).

 

Thanks for all the advice! A friend called me this morning and told me that he has a brand new universal converter sitting around that I can put on for going through emissions! I just went to pep-boys to get all the adapters to fit it to my exhaust (it doesn't have the brackets at the ends like the stock cat). Only problem now is that it's pouring outside and the Z is sitting in my parking lot with the exhaust entirely disassembled. lol

 

So what did you set your timing and idle to? When my Z warms up it's usually idling at 700-800 rpms, and I've never even messed with the timing in all the time I've had the car.

 

Like I said....I didn't mess with the timing the last time. I cranked the idle all the way out. As far as it would go. And I also have a brand new AFM, and other ignition parts I bought. Here I will find the thread, I made after I passed. Here you go. I posted the link for the thread for you.

https://www.zdriver.com/forums/280zx-s130-forums-77/i-passed-smog-nazis-again-23884/

 

Put on the cat, raised the idle to 1000, leaned out the fuel air mixture, and guess what...

 

0 HC under load... that's one clean runnin car!!! That's how my 325i is... surprised the crap outta the inspection tech.

 

Nice bro', congrats man. Yeah raising the idle, makes it run a little cleaner. Because it is more free-flowing. Also of course you leaning out the a/f mixture. I am sure helped a lot too. Good job, and congrats once again.