'92 SC300 Emission test fail
Thread Starter
Driver School Candidate
Joined: Jan 2006
Posts: 23
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From: mo
'92 SC300 Emission test fail
I just bought a '92 SC300 w/ 194k. It passed safety test ok, but fails on the Missouri Emissions Test. I have changed the oil, plugs(Denso Double Plat) and ignition wires. Runs smooth with no CEL.
Any ideas before shelling out the money for engine emissions diagnosis?
Any ideas before shelling out the money for engine emissions diagnosis?
CL Community Team
Joined: Apr 2004
Posts: 17,338
Likes: 213
From: Miami, Florida
You can have no CELs and there can still be a problem that your ECM cannot uncover from your your cats or O2 sensors.
One thing I do with my uncle´s cars down here is evaluate the emissions test findings over the years (you can bribe to pass down here if necessary) and I usually find that even when we do some of the things you did, very little decrease.
A lot of times there is buildup in certain parts of the motor (not ncessarily that the cat is plugged) or even on the O2 sensors, but not enough to trip up a CEL. The wavelength detected after the cat by an O2 sensor may show normal, but actually there is buildup in the engine that does not make for the best combustion gets detected within an emissions test.
Cleaning IACV, EGR Vavles, intake, throttle body, an engine flush with new oil and filter, using techron fuel additive...are just a few of the things we do down here and I know some other CL members do, too. I am sure others have their favorite methods.
One thing I do with my uncle´s cars down here is evaluate the emissions test findings over the years (you can bribe to pass down here if necessary) and I usually find that even when we do some of the things you did, very little decrease.
A lot of times there is buildup in certain parts of the motor (not ncessarily that the cat is plugged) or even on the O2 sensors, but not enough to trip up a CEL. The wavelength detected after the cat by an O2 sensor may show normal, but actually there is buildup in the engine that does not make for the best combustion gets detected within an emissions test.
Cleaning IACV, EGR Vavles, intake, throttle body, an engine flush with new oil and filter, using techron fuel additive...are just a few of the things we do down here and I know some other CL members do, too. I am sure others have their favorite methods.
Lexus Test Driver
Joined: Oct 2005
Posts: 1,292
Likes: 0
From: The BIG Apple
Originally Posted by SC4-94
I just bought a '92 SC300 w/ 194k. It passed safety test ok, but fails on the Missouri Emissions Test. I have changed the oil, plugs(Denso Double Plat) and ignition wires. Runs smooth with no CEL.
Any ideas before shelling out the money for engine emissions diagnosis?
Any ideas before shelling out the money for engine emissions diagnosis?
If so you should have taken it for a good drive ( half hour or so at say 70mph) up on a highway/freeway just prior to your emissions test.
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