Hi, everyone,

I'm new here, but was hoping you guys might give me some tips on getting a 1994 V6 4runner to pass the California smog test. It seems like it's pretty close to passing except for HC. The results are as follows:

@15mph/1831rpm
%CO2: 15.0
%02: 0.2
HC (PPM): 107; Max: 88
CO (%): 0.20; Max: 0.64
NO (PPM): 494; Max: 508

@25mph/1794rpm
%CO2: 15.1
%02: 0.1
HC (PPM): 78; Max: 53
CO (%): 0.15; Max: 0.77
NO (PPM): 354; Max: 761

Can anyone give me some tips on how to get the HC numbers to come down? Will changing the timing help? How about using premium fuel? Any help is appreciated.

 

Ummm, slip the tester a Franklin?

Just kidding - Try here:

http://www.smogtips.com/six_things.html

http://www.smogtips.com/passing_inspection.html

There are tons of bottles of additives that you can toss in your gas tank that guarantee that you will pass the emissions test. How well they work, I honestly don't know - never tried any, but most offer a money-back guarantee.

Other things you might try -

Replace the spark plugs, and make sure they are gapped correctly.
Clean the throttle body.

~Bill

 

The largest cause of high HC is due to a dirty air filter. If recently replaced, then run a can or two of berrymans injector cleaner through the tank, and as bill suggests, replace plugs, dist cap & rotor, and clean TB and MAF.

 

Also, make sure you're using the lowest octane (87) gas. It actually burns cleaner than the 'premium' stuff.
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