hey guys i have a 1991 318is with a `95 S50 motor in it and have had trouble passing smog...suprisingly enough it passed inspection and what not. i have a custom exhaust with a new cat, 02 sensor and muffler that was put on about 3k miles ago. the engine has had new spark plugs within 3-4k miles. the engine itself has about 65k mi. area. im running the stock S50 OBDI computer with 91 octane (highest you can get in CA) the papers say that i need to check/repair high HC emissions and check/repair high NOx emissions. in the HC department i measured 152 at 15mph (MAX: 85) and i measured 59 at 25mph (MAX: 50) i also failed NO at 15mph measuring 743 (MAX: 695) but passed that at 25 mph measuring 21 (MAX: 717) it's obvious that the testers could def. pre heat the cat better but i am going through a refree because of my engine swap and they go right by the book cause they are dicks...but if anyone has any tips/advice i would appreciate it greatly. thanks.
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anyone have any insight? -
Did you get the test done with the cats as hot as possible?Comment
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unfortunately i have to go thru a "referee" and they go by the book so they hardly pre-heat the cat which i think would def. help. i had done a misshift last spring and screwed up my Vanos, pressure plate etc. so i threw in a new clutch, pressure plate and vanos and did a compression test getting 190 all across but im wondering if i have a bent valve(s)...it still runs pretty strong and smooth though.Comment
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Just drive the car around for awhile before you go to the station... that'll get the cat pretty warm. They preform alot better the hotter they are.
If possible, try to rev the engine up some right before the test.
If you have belt valves, you would have other problems.Comment
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