I did a full tune up but didnt gap my spark plugs. (was .030 instead of .044). Now before i go out and spend any money on repairs could the spark plug gaping be the problem?
So its just the NO ppm that failed, all others are pretty low. Also i noticed that on my last etest that i passed the rpm was @ 2778 for 40km test compared to the 1803 this time. My gas millage was lower too with the wrong gaping.
Might want to take out and clean your EGR valve, as its the only emission system that controls NOx. It might not be opening as much as it should and allowing inert gas back in to cool down your cylinder temp.
I had the same problem when I purchased my car, my results were almost identical to yours, flying colours throughout everything except NOx emissions.
Clean that dirty EGR valve and all the related passages. It’s a bitch to get to behind the engine, though.
The way it works is: by letting inert exhaust gases recirculate into the combustion chamber, the combustion’s heat is partially absorbed by the inert gas and the lower combustion temperatures that result produce less NOx emissions. These nitrates are predominantly formed at very high temperatures, so you will pass your e-test afterwards.
you should go back and tell the inspector to test it ln second gear like it is supposed to be not 3rd like he did and run 87 octane if you are really worried
yes it will lower combustion temperatures as the higher the octane rating the hotter the burn.
if you really want to make sure of it passing leave it outside the shop over night and make sure it is tested stone cold in second gear as it is supposed to be but if it is tested properly it should pass. if you do go back you should not have to pay for the second test as the first one was done improperly and if they want to argue with you there is a 1800 number on the bottom of the report that they gave you, call that and tell drive clean that you think they tested the car in third gear and would like to know what options you have.
just trying to help let me know if you have anymore questions regarding emission tests.
Ok. When you test a car in second instead of third the NOx will be higher… higher RPM resulting in higher cylinder temperature. 91 octane does burn hotter but if you test it in second gear with 87 octane it may start pinging… depending on the setup. Pinging will make high NOx readings too.
BTW the test could have been done properly. because at the time of the test the RPM could have been unstable in second gear resulting in having to test in 3rd. You could always try to get a test out of them… or test it somewhere else and send in a complaint about the place that tested it in third.
Also the egr valve isn’t the only thing that controls NOx. There is many different things. Coolant temp, Bad MAF (lean), Bad O2, Vacuum leak, Bad Cat, Improper timing.
Since the NOx arent really that bad, I would make sure basic things are good. Ie. Make sure that there is no check engine light on, that there is proper coolant flow (all hoses hot and thermostat open) Get the Cat hot. If you did all that. Turn the heat on full blast (tell the guy testing it to leave it alone)
Try retarding your timing if you have a distributor, I found this works very well.
Yes testing it cold will work too, but that is frowned upon because it goes against the SOP and chances are if you don’t know the person they wont do it. They dont have to test it cold just because you say it. They also don’t have to test it again for free because someone thinks they did the test wrong. A bad tach connection could also be the reason why that number is so low.
