I got a '90 civic D15b1 that failed emission test. It failed on the NOx ppm reading 1831 out of 1440 allowed on the 25/25 test; and 2085 out of 1577 allowed. The guy that did the emission said it is not burning the fuel as it should in order to pass oh and also I forgot the other guy that worked there timing should be adjusted (he guess). Any helpful tips, suggestions or if anyone had a similar problem sharing it with me would be appreciated.
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