failed emissions, Texas :(


I drive a 94 integra 5speed. I've had my car inspected twice in the past week, and my car only fails the emissions. I had an oil change two weeks prior, and I do need a tune up. The readings the first time That failed were:
Low speed Hc 255 (standard 146)
Low speed co .96. (.82)
High speed NOx 1962 (1026)
Low speed NOx 3090 (1134)
Since my car is twenty years old, I figured my car just needed some cleaning so I bought the "guarantee to pass" stuff at auto zone. Driving a full tank to a fourth tank took me eight hours of hard driving, and I still didn't pass the second time.
Low speed NOx 1935 (standard 1026)
High speed NOx 2041 (1134)
I am barely not passing, and the stuff cleared up everything else. I might need to replace the catalytic converter. My question is, would buying another guarantee to pass do the trick, or should I just go strate for replacing the cat? I also havent tried the sea foam method. I've owned this car for a few months, and I have no idea how old the cat is. My guess is pretty old since 90% of the car was stock when I got it. I'm leaning towards replacing the cat but that can get expensive.


Reppin' tha NW
Check that your engine timing is spot on.

Bust out the timing light. Confirm cylinder #1 is firing within factory specs indicated on the 3 marks on the crank pulley.

If all those are ok. Proceed to find a voltmeter capable of 20v dc.

Ground the black probe, insert red probe into your tps. The red wire is the one you want to probe.

Your volts should read somewhat close to .48 volts closed throttle. 4.5 volts wide open throttle.

There's a guide somewhere to readjust the tps. .48 CT and 4.5 WOT is what you want. This must be dead on.

If all these problems don't fix your issue, it could just be your car but all these fixes shouldn't cost more than your time, if you have the tools.


My readings were a bit off. I got my car tuned and that seemed to do the trick. I took a better look at it with my mechanic and yeah, just an old cat. I just didn't have the money at the time to replace it. I was just seeing if anyone knew any tricks that I couldn't find on Google to buy me some time. I got a discount on the cat and a warenty just because I got a full tune up done. That was pretty cool.

On a side note to anyone who reads this, guarantee to pas is pretty awesome, but it won't lower the Nox levels very much. I did more research on it and found that that's pretty common. I still recommend it. My girl felt pretty great afterwards.