I have a 94 Accord Ex. I failed the NOx ppm part of the test. The allowed was 1006 my car did 1271.

The guy said that is was reading to much nitrous oxide. He wasn't sure what was causing it. The Catalytic Converter or the EGR system or even the O2 Sensor could cause it. Do you have any Idea what could be causing this? I have 176,000 miles on the car.

 

i would clean the egr ports and inspect the o2 sensors


rotary buzz on ht has some tips in his sig try reading what he has it may help you ...

 

what does all the abbreviations you use mean?

 

EGR = exhaust gas recirculation

02 sensor = oxygen sensor

NOx = nitrogen monoxide and nitrogen dioxide


A great place to start is the EGR ports. You will need to take it to the dealer to have them cleaned. There's a plate they will remove to clean the carbon build up in the intake manifold.

 

Cool I was able to remove the plate and remove the carbon out of the ports. I used a vacuum to remove the carbon after scrapping. I hope this helps in the emissions test. Would I have noticed a differences in performance, idle etc...

 

If your EGR ports were clogged enough (as mine were), your engine would stutter at partial throttle (around 2500rpm). After I cleaned mine the stutter went away as well as the EGR and Cylinder Misfire CEL codes I was getting. I am sure that cleaning the EGR ports will help your emissions (most likely the reason), but that is not necessarily why you failed.

My car failed after I recently cleaned the EGR ports (we don't test for NOx here though). I replaced the cat and O2 sensors and it passed like a new car. The funny thing was that it failed the idle test once even with a new cat an O2 sensors after idling for 30 minutes in a 90+ degree garage. The mechanic determined that the engine wasn't heating up to operating temperature to activate sensors. He covered the radiator, temp went up 12-15 degrees and it passed like new. Think my thermostat is sticking open.

Just something to consider if all else fails.
Good luck, inspection/emissions are so annoying. You forget about it all year than something happens and your scrabbling to make it pass

 

Thanks for the Help. I am going to attempt to run it through the emissions test again. I hope this works. I don't have the money for a new cat and o2 sensor.

 

what happened? Did i miss the party??

 

a restrictor plate always helps, and so does a decent ignition

 

Well I passed. The EGR Port cleaning worked. Thanks Guys. Now if I could only get some help with my Lack of power when I turn on the AC that would help. I know hondas have no power when the ac is on, but this loss of power is not related to that. There has to be something that is causing this lost of power.

 

Now my 2 of my injectors are leaking gas. Was I supposed to change the seals on the injectors after removeing them?