Seafoam helped me pass CA emissions!
Thread Starter
Supporting Maxima.org Member
Joined: Apr 2002
Posts: 305
Seafoam helped me pass CA emissions!
I know there have been a ton of Seafoam pro/con threads, but none discussed emissions in detail, and I wanted to pass along this information for those that may be struggling to pass CA's tough emissions.
Car: 1999 Maxima ES, 5 speed, Y-pipe, 125k miles, high-flow catalytic converter, generally good condition, running Amsoil oil since 60k.
After failing the CA emissions several times (mostly due to high NOx), and trying a variety of things to fix the problem (spark plugs, air/oil/fuel filter, EGR cleaning, new coolant/thermostat, switching back to the OEM cat, praying), I was running out of options. During the last failed test, the SMOG guy mentioned that Seafoam in the vacuum line may help reduce some deposit buildup and lead to better ignition, which would make the engine run cooler and reduce NOx. So I purchased a $10 bottle from him, went out to an unpopulated area, and did the sip/slurp method and watched smoke pour out of the pipe. 30+ minutes later, I went back to the SMOG shop. And PASSED! Numbers below:
HC_______Pass___Before__After
-15 mph___55_____77_____30
-25 mpg___39_____39_____21
CO_______Pass___Before__After
-15 mpg___0.50___0.17____0.09
-25 mpg___0.48___0.07____0.05
NO_______Pass___Before__After
-15 mpg___437____715____297
-25 mpg___724____342____383
Literally, the only difference was adding Seafoam in the vacuum line. The car was fully warmed up on both occasions. I was almost shocked. Anyway, I hope this is helpful to someone trying to get their old, trusted Maxima through a tough CA emissions test. Good luck!
Car: 1999 Maxima ES, 5 speed, Y-pipe, 125k miles, high-flow catalytic converter, generally good condition, running Amsoil oil since 60k.
After failing the CA emissions several times (mostly due to high NOx), and trying a variety of things to fix the problem (spark plugs, air/oil/fuel filter, EGR cleaning, new coolant/thermostat, switching back to the OEM cat, praying), I was running out of options. During the last failed test, the SMOG guy mentioned that Seafoam in the vacuum line may help reduce some deposit buildup and lead to better ignition, which would make the engine run cooler and reduce NOx. So I purchased a $10 bottle from him, went out to an unpopulated area, and did the sip/slurp method and watched smoke pour out of the pipe. 30+ minutes later, I went back to the SMOG shop. And PASSED! Numbers below:
HC_______Pass___Before__After
-15 mph___55_____77_____30
-25 mpg___39_____39_____21
CO_______Pass___Before__After
-15 mpg___0.50___0.17____0.09
-25 mpg___0.48___0.07____0.05
NO_______Pass___Before__After
-15 mpg___437____715____297
-25 mpg___724____342____383
Literally, the only difference was adding Seafoam in the vacuum line. The car was fully warmed up on both occasions. I was almost shocked. Anyway, I hope this is helpful to someone trying to get their old, trusted Maxima through a tough CA emissions test. Good luck!
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JoshG
4th Generation Maxima (1995-1999)
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Sep 5, 2015 10:10 PM