FAILED EMISSIONS 5kcsq Please Help

rizov_d at rizov_d at
Thu Jan 30 20:16:30 EST 2003

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Wht is the O2 %?

What are HC and CO; NX ?

(The engine might run to lean)


----- Original Message -----

From: John Larson <j.d.larson at>

Date: Thursday, January 30, 2003 2:17 pm

Subject: Re: FAILED EMISSIONS 5kcsq Please Help

> "There are three things that we used to always do (Toyotas, VW's,
> Hondas) to
> pretty much guarantee a pass:
> 1a) Fill up with Premium gas.
> 1b) Change the oil
> 2) Change the spark plugs
> 3) Get the thing DARN hot"
> While some of these are good ideas, one is MOST ASSUREDLY not.
> The higher
> the octane, the poorer the burn, especially at idle. You want to
> run the
> lowest octane the car will stand for an emissions test. Better
> burn = lower
> HCs. Hasn't anything to do with the CO%/volume. Spark plugs also
> have zero
> affect on the CO. Big effect on the HCs.
> Now. On to the real problem. If the mixture is THAT high, there are
> several things to check. First, the timing and idle speed need to
> be set to
> specs, then the coolant temp sensor for the integrated Lambda
> system needs
> to be tested. Unplug the O2 sensor when the car is hot and see if
> it cleans
> up. Bad O2 sensors often make the engine go full rich. Test the
> outputvoltage for both voltage and rapid fluctuation. Make the
> fuse for the FI
> system, often mistaken for a spare, is in there (side of the
> fusebox). Once
> those items are done, you can simply adjust the mixture with the
> littlescrew in the airflow meter, right next to the fuel
> distributor. Adjusting
> it without verifying the other things can be a BIG mistake.
> Follow the
> procedure in the Bentley. A catalyst, BTW, has relatively little
> effect on
> the CO, and the same is true for engine oil dilution. Both affect
> the HCs
> big time.
> HTH, John

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