Help! Failed emissions
 

My 86 Z failed exhaust test. High in hydroCarbons and oxides of nitrogen. Any quick clues to correct this, plugs, ecr, coil, tune-up items?

Re: Help! Failed emissions
 

After a basic tuneup and oil change the CHTS, o2 sensor, and cat are the best suspects.

ZenArcher

Re: Help! Failed emissions
 

make sure you check the vac hoses, and set the timing properly.

try using ngk plugs, not bosch. bosch ones run hotter, and higer heat in the combustion process will drive nox emiisions up.

one way to test the cat, is to take temp readings just before and just after it. coming out of the cat should be about 150 degrees hotter than going in.