what does it mean when the NOx levels are too high for an auto emissions test?

Question

I've heard to put about 3 bottles of HEET in my car and rev up the engine to fix this problem. The NOx limit is 2.00, my car had 3.5085 at the time of the test

I had my oil changed about two days

Answer 1

Adding any chemical to your fuel or crankcase for NOx is a waste of your resources.
NOx is the result of combustion where the cylinder temperatures exceed about 2500 deg. F.
Most cars today have a device to help reduce NOx. It is called an EGR valve, and it recirculates burned exhaust gasses back into the engine to reduce the heat (efficiency) of the cylinders. There is neither fuel or oxygen in this gas, so it merely takes up space in the chamber without contributing anything.
Also a part of the emissions system is the Catalytic Converter. Its purpose is to reduce excess Hydrocarbons (unburned fuel), Carbon Monoxide (partially burned fuel) and NOx, (Oxides of Nitrogen).
If the Rhodium bed of the cat has deteriorated, it may have been the cause of your NOx failure.
Also programmed into the computer is a routine for further NOx reduction.
If you are unfamiliar with emissions diagnostics, even though you may have to spend some money, you will be better off taking your car to a Licensed Smog Repair facility, at least for diagnostics.
This is something that many (even mechanics) don't fully understand, and you can wind up spending a wheel barrel full of money, and STILL fail again.

Rule of thumb----->There is no satisfying chemical answer to a mechanical issue with your car.

Good Luck

Answer 2

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RE:
what does it mean when the NOx levels are too high for an auto emissions test?
I've heard to put about 3 bottles of HEET in my car and rev up the engine to fix this problem. The NOx limit is 2.00, my car had 3.5085 at the time of the test

Answer 3

High Nox Emissions

Answer 4

What Nightranger said, and then some.

The NOx level in particular refers to the levels of certain toxic nitrogen-oxygen compounds. NO2 is OK; that's the gas that air is mostly made of. But burning fossil fuels also produces NO (nitrogen oxide, which is toxic) and N2O (nitrous oxide, aka laughing gas, also toxic and hallucinogenic to boot). Basically, a high NOx level means that the car is polluting more than it should. Nightranger's response explains some of the possible reasons why it might do that.

Answer 5

High Nox

Answer 6

Does the UK MOT test put a limit on Nox level or just on carbon levels

Answer 7

nox if formed from excess heat, you have carbon buildup in your engine, try taking it to a shop have the oil changed and a induction and fuel service done, you need the engine and back of the valves cleaned so the deposits wont form heat and create excess nox, also have the egr system checked out.

Answer 8

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HC is hydrocarbons. That means you are not burning the fuel efficiently. It could be that you just need a good tune up, it could be something as simple as a clogged air filter. It could also be that you are burning oil, and have major engine problems. Have the car checked by a qualified mechanic!

Answer 9

It means that the combustion chamber temps are too high. Could be cause be a lean fuel mixture, defective EGR valve, bad catalytic converter, or too much alcohol in the fuel system (HEET, for instance)