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emissions failure

coltman's Avatar
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05-24-02, 07:09 AM   #1  
emissions failure

I have a 1994 colt with a 1.5 engine and have just failed emissions test for nox. all other test were ok. hc was well within the limits and co% was also well under the limit. the nox reading was 1894 and the limit is 1304. Are there any specific areas on the car where I can look to solve this problem.

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Joe_F's Avatar
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05-24-02, 07:52 AM   #2  
Bad air pump, leaks in the air injection system (pipes, valves, solenoids), bad EGR valve, etc.

Those are common causes for high NOx.

The timing could be off or the car could have cooling system troubles which will also contribute to the problem.

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06-07-02, 06:41 PM   #3  
had same prob with my 86 olds;car ran great but failed em. like u did, egr valve was the prob.

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06-07-02, 10:16 PM   #4  

I would first make sure the egr valve works, make sure the passages are clear,then I would drop the timing back about4-6 degrees.make sure you are not running hot.try a valve cleaning additive your valves may have deposits causing a lean mixture.your car car will run like a pig after you retard the timing,but if you scribe a line on the dist you can put it back after the test.

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