Passing Emissions tests

[hondo21]

I'm a new member with an 84 300ZX non turbo with a 5 spd & T-tops that we just bought a month ago. Its a blast to drive and a great project for my son & I.

We took it to get inspected and the car failed due to high HC and OX? readings. Prior to this, I had replaced all spark plugs and distributor cap. I have also checked the timing and found it at 25 BTC. It has an aftermarket intakre filter on it that's clean as well and we've had the oil & filter changed.

What should I do next? I ordered a new Oxygen sensor and plan to put that in. I couldn't believe the price I was quoted on a new ERG valve - $120, so we didn't get that. I don't want to resort to taking it in for service and find this forum very helpful so my son & I can do the work on our own.

Thanks!

[AZ-ZBum]

more likely the catalytic converter.

[Amesdude25]

I concur... I just purchased an 87 zx and it was just a few points off on each. It was the cat. Fairly cheap item though, around $120. My mechanic charged me $400 for the cat and instulation, smog, minor emissions tweeking. The smog alone in CA is $90 so I think I got a pretty good deal. She passed with flying colors and 150k miles to boot!

[hondo21]

Thanks guys. The exhaust does sound a little rough, so I'll check this out & let you know.

[NSR240sxe]

I agree, check the cat out. If you shop around you can find them pretty cheap and if you're handy do the replacement yourself

[NISTECH]

Guys its probably not the cat. Even in your cases it probably wasnt the cat. A cat goes bad from poor engine tuning. Yes putting a freash new cat on will getcha through this time but you are only going to smoke your new cat, it depends on how your mixture is on how long it will last.

Post all your numbers from the test, not just the ones that failed. If you do I can mathmatically figure out weather its the cat or an engine effeciency problem.

[hondo21]

Just wanted to let you know we replaced the cat and she passed like a breeze. Sounds much better too.

This forum is great & I appreciate everyone's help!

[NISTECH]

Ok give me your passing numbers and I will tell you if it was the engine. And weather your going to burn up your new cat inside of a couple years.