Smog Test FAILED!

[jerryho]

I went for a SMOG CHECK (test only station) due to an upcoming registeration renewal and my 91 NSX failed.

Here's the partial reading... anyone know what I need?

HC (PPM) CO (%) NO (PPM)
15 mph 1535 RPM 219 (max is 114) .96 (max .73) 1086 (max 785)
25 mph 1755 RPM 124 (max is 88) .21 (max .61) 236 (max 724)


(max figures) is the maximum allowed for that test. I'd be honest, I've put less than 2500 miles on the car this year... and the car has not been driven for 3 weeks before I did this test.

But again, 2 years ago, the car barely passed. Some say I need new CATS and others say O2 sensors. Any ideas?

Thanks in advance.!

 

[Racerxjling]

How many miles are on the car? Did you get the cats nice and hot before the test?

Jeff

 

[nis350]

have heard many earlier NSX failing smog check lately....

Try the RXP gas additive from AutoZone. Some members indicated that it worked for them. Also run your car at high rpm right before the test.

 

[DRIFTER]

Get the car good and hot, do not shut the car off pull it in and hook it up.

O2s are alot less $$$$$ then a new cats try that 1st:smile:+replacing the o2son a 91 car cant be a bad thing.
If you need the cats get the ones from SOS.

 

[RON98]

run your car hot, do a tune up, retard timing, 1 can of octane, thats our winning formula. :biggrin: .

 

[Jap4RE]

ah the efficiency of the EPA testing, nothing a little tuning and wisdom can't fix. :wink:

 

[RON98]

cant stress how many cars you can pass with a little know how.

recently just passed a car with the primary cat gutted, at the time i had no idea, just thought it was old. :smile:

had to take off the cats for a turbo install and could not believe it.

 

[mickeylex]

run your car hot, do a tune up, retard timing, 1 can of octane, thats our winning formula. :biggrin: .

All good advice to help pass.

Also, check your spark plugs - make sure they are clean. Use a clean air filter. Clean throttle body. Drive car around for a couple of days (since you haven't driven it much). On test day, drive car around for at least 30 minutes first. Then go straight to the test center and get tested right away. If you have to wait, leave the car running and wait in the car. Make sure they turn the TCS off when they run the test.

 

[jerryho]

Thanks everyone. Going to try a pair of new cats from random tech first. They seem to be a bargain compared to OEM.