Stock KA failed Smog

[240Stilo]

Well to get specific, at 15mph the hydrocarbons were at 88 which is the maximum. At 25mph they were at 71 where 53 is the maximum. Aint that a bitch. Well anyways, since the odometer has 146k, would I be right in assuming I will be needing to purchase a new cat to pass?

[Var]

no you cant assume that but it's possible. Check your plugs and air filter first. Make sure they aren't dirty. Also get an oil change(if it's dirty) cause it helps. If you want to just throw parts at it without getting it diagnosed first, the cat is probably the best bet. But check the things a listed cause they're easy.

[cdlong]

try running a injector cleaner or a cylinder cleaner too, cause carbon and oil deposits can contribute to HCs. make sure the engine is fully warmed up too.

[SauN]

replace cat. converter if you haven't already. A new cat. converter will hide ~80% of the problems especially if you're failing hydrocarbons.

Otherwise, I would just do a tune up and replace plug, wires, rotor, cap, air filter and change oil if you are not planning to sell your car.

[idlafie]

Well to get specific, at 15mph the hydrocarbons were at 88 which is the maximum. At 25mph they were at 71 where 53 is the maximum. Aint that a bitch. Well anyways, since the odometer has 146k, would I be right in assuming I will be needing to purchase a new cat to pass?

Juan,
You might have better luck getting replies if you would have posted this in the TECH forum.
Anyhow, getting to your smog problem your CO & HC readings could have been high for any of the following reasons:
A dirty or clogged air filter, a bad 02 sensor, poorly adjusted idle, excessive carbon buildup in the throttle body and/or idle adjust valve, timing off, EGR system or Fuel Pressure Regulator system malfunction - usually a cracked or leaking vacuum line, a bad/leaky fuel injector and finally your assumption of possibly a bad catalytic converter. Not sure but maybe even a dirty or clogged PVC valve. What year is your 240? S13 or S14?? You didnt say in your post.

Anyhow, test the cat & vacuum lines by doing a vacuum gauge test of the vacuum lines. Attach a vacuum gauge to a full vacuum source. A good place to connect to is the charcoal canister. There
should be three hoses connecting the carbon canister. Two of the hoses go to a purge valve that's built into the canister. The second larger hose off the purge valve should be your vacuum line. With the motor fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be 21 InHg. Anything higher will tell you of restriction in your exhaust system...melted cat. Anything lower will be a vacuum leak.

Try solving your problems by changing your ail & fuel filters, changing your spark plugs, distributor cap & rotor AND check with an ohm meter / continuity tester your spark plug wires...at 146K miles you might want to consider replacing them. Put your ECU in diagnostic mode & check for any DTC codes from your ECU. Also check the 02 Sensor while the ECU is in diagnostic mode. Go to the www.240sx.org website & click on the FAQ link. Once the page opens scroll down till you get to the 02 Sensor link...click on that link. It will tell you how to check your O2 Sensor to see if it is working properly.

If you're asking how I know all this, it's because I've failed smog twice on my 95 S14. Once cuz a crooked smog test tech wanted me to buy additional services from their crooked shop so I could pass smog, (I found out what they did two weeks later when I went to change my oil. The dumasses tampered with my 02 sensor to intentionaly get my car to fail smog, but the dumasses didn't bother to fix the wires they tampered with!! I reported them to the California Department of Consumer Affairs, Bureau of Automotive Repairs & got ALL my money back...except for the $6 dollar smog certificate. And the second time I failed smog was because of a MELTED catalytic converter...but that was because I was running rich due to a misadjusted idle.

Anyhow, hope all this stuff helps...
Diego
member...www.SoCal240SX.org

[holisticbeatz]

There's this thing you can buy at GNC that you drink, it'll hide any traces of THC in your urine. Passed every time!

Ooops.. you're talking about Smog testing.. Sorry.. Yea, try changing the cat and testing when your car is running at normal operating temp.

[240Stilo]

Borrowed a cat and some spark plugs and passed thanks for the replies.

Holisticbeatz: thanks for the info haha.

[the240sxer95]

i hope i pass my test soon, i am gonna remove my ka turbo off my 97 and return it to stock, how everything goes well.. any tips for me? anything i should check or change when going back to stock?


-sorry to hijack