So got my camry safetied and took it in for an etest and the NOX failed badly. Now the last etest the car got was 2 years ago and it passed NOX but barely, 2 years before that the NOX was almost ZERO so its been increasing over the last few years when my dad owned the car.

My NOX limit was 3 times the limit but I think this was my fault. I knew it would be close so I added some Colmanns Camping fuel which I was told COULD lower the NOX limit, but in some cases it can also INCREASE the NOX, looks like it increased it for me. I put in 4 liters of the fuel for half a tank, I was told if the percentage is above 3 % it should lower the NOX not increase it. But oh well. I have since filled the tank to dilute the camping fuel which is NAPTHA.

SO I am going to run the car for a few days to help get rid of the Naptha, and I have soem methal hydrate as well to try.

I think the EGR may be an issue as well, as this is what usually causes high NOX, how hard is the EGR to remove and is it possible to clean them to make them work better, I know on other cars I have had you could clean them. I have a parts car I can take an EGR from as well. I am getting no check engine light from the EGR though but thats my best guess. The exhaust was replaced with factory Toyota exhaust not long ago so I don't think its the cat.

 

Per your info the tank would have about 12% naptha. This may be one reason for your problem. Most injection cleaners, etc state to add about 1 pint per tank.

You should be able to find EGR system cleaning procedures on the web, type in "EGR cleaning" and your engine model.

 

Youtube always has some good videos.

 

yeah I read that as long as its above 3% it should decrease the combustion temps and thus decrease the NOX reading. I was reading that guys put in 4L to 1/8 a tank, where as I had 1/2 a tank. Oh well, I should have tested the car first to see how close it really was, may have passed by itself, haha. Live and learn.

I know how to clean the EGR, just wondered how hard it was to get at it on the Camry. I am still new to this engine, I am used to working on Ford Mustangs. I don't think it will be too hard to get at but wondered if there were any tips or anything that anyone had, like DON'T do this, or make sure you do THIS first.

From the pics I took of the cat, it looks fairly new, the heat shield still looks new although the cat is rusty but so is the rest of the exhaust. Its new exhaust front to back from Toyota a few years ago, so its all stainless, so the rust is just surface, I am going to change/clean the EGR then consider the CAT as a possibility

I also have the spare motor I can take the EGR off and clean so I can keep driving the Camry to help burn off the Naptha.

I appreciate the help guys, this site is great for fast replies.