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  1. #1
    Join Date
    Jul 2010
    Location
    Southern California
    Posts
    58

    MkIII Smog Check results...need some help

    got smog results for a 7mge 1986 supra. failed miserably...any suggestions on what to look for? I know this is a mkII forum.

    these are the categories it failed in:
    HC-122@15mph
    NO-1240@15mph, 794@25mph

    there is also a high pitched noise coming from the engine when it is above 3000 rpm, which I am guessing is a vacuum leak, but cannot pinpoint by spraying the intake with wd40 while the car idles.

    also of note: a little over a week before I smog again...I need to fix this ASAP.
    '82 L-Type//'83 P-Type//'84 Celica GT-S Convertible//'91 Miata

  2. #2
    Join Date
    Mar 2003
    Location
    SF Bay Area
    Posts
    5,412
    Check EGR vacuum circuit...for NO could be clogged EGR

    HC usually means bad O2 sensor...
    Regards,
    Arch
    '86 Supra MA67
    Brullen 2.5" Exhaust, HKS Fly w/7MGE clutch,ST Springs, RC Intake & TB, 2.8GT & XX emblems, Factory Add on Rear Shoulder belts, Pioneer DEH-P2000 AM/FM/CD w/CDS-P5000 CD Player, Compomotive CXNs 8x16

  3. #3
    Join Date
    Apr 2003
    Location
    Livermore, CA
    Posts
    69
    Check out http://smogsite.com/calculators.html
    Plug you numbers into the Lambda calculator(air/fuel ratio calculator)
    Generally speaking a high CO reading indicates a rich condition because their is not enough O2 to make CO2.. NOx forms under high heat or pressure. Rich mixtures burn cool and should not generate too much NOx. So if all these numbers are high(HC,CO,NOx) you may need a catalytic converter (Best way to tell is to test exhaust gas before cat for a conversion rating). Those cost some money so double check the basics. If your fuel ratio was lean check for VACUUM LEAKS!/INTAKE PIPE LEAKS!,O2 sensor,low fuel pressure. The Manual has a good flow chart for testing O2 with analog volt meter. If you have a vacuum pump(some part store might lend with deposit) apply vacuum to the EGR valve and the engine should stall or nearly stall. Also test modulator stuff that's in the book.
    I have heard the valve clearances can effect emissions too. carbon buildup in combustion chambers may increase nox.
    Magnaflow 36767 Direct Fit Catalytic Converter is 214 on amazon.
    catco 65166 Direct fit converter at summitracing for 177.
    walker 80540 direct fit converter also 177 at summit.
    There is also universal ones available, but you'll need it welded in place. check manufacturers website.
    Stock one is probably the best but at least $400. That's about what I paid for a rear 7mgte cat from Mark at Vancouver Toyota several years back.
    You could also look at smogcheck.ca.gov for CAP(consumer assistance program) information. If you qualify(test-only directed cars can qualify without being low income candidate), you can get up to $500 in emission repairs at gold shield stations after you pay for the first $100. Some BAR field offices have set up ways where you can get approved very quickly, instead of the several weeks it used to take.
    '84 p type 5mge 5spd.

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