4.0 V8 emissions numbers

[pavel]

Hope someone is knowledgable about emissions......

Went through "Aircare" yesterday and passed! I was expecting to fail as my oxygen sensors are original (10 years old). The numbers are interesting but confusing. Here are the data:

240 second......... / Maximum // Vehicle ///Average passing ////Result
Driving test......... / Allowable //Reading /// Reading

Hydrocarbons...... / 0.5000 // 0.0588 /// 0.2433 //// PASS
grams/km

Carbon monoxide .. / 8.0800 // 0.7846 /// 3.8783 //// PASS
grams/km

Oxides of Nitrogen / 1.1200 // 1.0360 /// 0.4527 //// PASS
grams/km

You'll note that the Hydrocarbons (unburnt fuel) and carbon monoxide are both very low - roughly 1/10th allowable amounts. The oxides of nitrogen however are over double the average passing reading. Why would the NOx gasses be so high? Can anyone explain? Thanks.

[Disco Mike]

The test that is performed has very high standards, meaqning they give you alot of lee way when being tested.
I recently had my 99 D2 tested after moving into Colorado with nearly 60,000 miles on the plugs and wire and a clean crank case. My highest test came back at about 2% of the allowable measurement..
The test is nearly worthless cause most vehicle will pass even when running poorly. If they really wanted to clean up the air, the range of tollerance would be so high that most wouldn' pass and people would just complain.
As for your 10 year ols O2 sensors, if you have or 100,000 miles on them, your truck would run better, get better MPG and performance if you would replace them.
Mike

[pavel]

Yes, I understand that the threshold for passing these emissions test is 'politically' set but why would one of the indicators give poorer results than the other two? It has been almost 40 years since I took that horrible 'thermodynamics' course in 2nd year college (I didn't understand it then but managed a pass)..... Surely if combustion is (relatively) complete, resulting in few unburnt hydrocarbons & little CO compared to CO2, then oxides of nitrogen should be at the expected level also, not in excess..... As you can tell, my understanding is feeble.

Our 96 D1 has only 33k miles and has, I think, a very clean engine - heads removed and decoked 18 months ago. Perhaps I should up-date the plugs and wires anyway?

[buick215]

Here in the UK our annual inspection includes an emissions test which is done with the vehicle stationary.It does not does not include a Nox test as this really needs to be done with the engine under load to be accurate,ie on a rolling road.
Could someone please enlighten me as to how your tests are carried out in the US ?

[Adam in NYC USA]

Originally Posted by pavel

Hope someone is knowledgable about emissions......

Went through "Aircare" yesterday and passed! I was expecting to fail as my oxygen sensors are original (10 years old). The numbers are interesting but confusing. Here are the data:

240 second......... / Maximum // Vehicle ///Average passing ////Result
Driving test......... / Allowable //Reading /// Reading

Hydrocarbons...... / 0.5000 // 0.0588 /// 0.2433 //// PASS
grams/km

Carbon monoxide .. / 8.0800 // 0.7846 /// 3.8783 //// PASS
grams/km

Oxides of Nitrogen / 1.1200 // 1.0360 /// 0.4527 //// PASS
grams/km

You'll note that the Hydrocarbons (unburnt fuel) and carbon monoxide are both very low - roughly 1/10th allowable amounts. The oxides of nitrogen however are over double the average passing reading. Why would the NOx gasses be so high? Can anyone explain? Thanks.

It is recommended that you run the engine on the road for 20 to 30 minutes beforehead so your cat convertor comes up to operating temperature.

Cats work best when hot. When they get older, the convertor does not work as well and is a pricy thing to swap out.

So what can you do? Show some love and spend some cash.

Your o2 sensors are at the end of life. Replacing the sensors can only help you with the emissions and your fuel efficiency.

New wires and spark plugs will also improve, as well as a oil change and a fresh air filter. So will properly pressurised tyres.

Until you rechip your LR, run with either Seafoam or Techron , use premium fuel, and enjoy your ride.

[Adam in NYC USA]

Originally Posted by buick215

Here in the UK our annual inspection includes an emissions test which is done with the vehicle stationary.It does not does not include a Nox test as this really needs to be done with the engine under load to be accurate,ie on a rolling road.
Could someone please enlighten me as to how your tests are carried out in the US ?

In NYC, we are doing a running dyno test along with a ECU reading. Any Check Engine light is a automatic Fail. Unfortunately, most bill just to read and clear the code.

New York adopted the California/Federal standards, the strictest standards in the United States. I understand the MOT probably still kicks more ass.

[pavel]

buick215: here in Britsh Columbia, the emissions test involves running the vehicle onto a double set of rollers so that the test can be done in the testing station. There are fans providing air to the front and of course sniffers up the tailpipe(s). The test takes 240 seconds during which the vehicle is accelerated hard up to highway speeds, run at cruising speeds, rapid deceleration etc.
If the vehicle is 1998 or younger, a quicker test is possible if the ECU's records show cleanliness. We pay $45 for the yearly test. If you believe the government statements/propaganda, the emissions testing has made a significant 30+% difference.

Perhaps the engine/cats were not fully warmed up as I drove only about 10-15 minutes to the testing station - as Adam in NYC points out, this may have influenced the NOx readings. Also, I turned the engine off while waiting 10 minutes in line...that was a mistake.

[Rovin4life]

who gives a rats ass what those numbers are.

important thing is you passed.

besides you can fudge the numbers with the equipment.


and trying to diagnose with emissions numbers is really hard. and more then likely you are practically throwing parts at something till it meets the so called numbers.

I know a few callie techs and they have nothing but derision for the smog tests.

they make you do some really asenine things like checking timing and other dumb parts of the test.

[Adam in NYC USA]

I always wanted to take one of those inspection machines apart. I always wanted to know what they were doing with that inductive pickup they place on top of the engine and how that CO/NOx pickup on the tailpipe works.

At one point, I almost designed a fake OBD2 port to throw the inspection. Maybe when things get more stupid, like mobile red light cameras and special pavement markers for 'proper' spacing intervals come here in the NorthEast.

[Rovin4life]

a bottle of oxygen can go a long way to passing.

[Adam in NYC USA]

Originally Posted by Rovin4life

a bottle of oxygen can go a long way to passing.

Actually it wont. You have to generate CO and NOx generations from a operating engine otherwise you automatically fail the inspection.

Now if you want to transport a pressurised (2000 psi)oxygen tank in a car, be my guest.

You will be in violation of your local fire regulations, you wont have the proper licenses, permits nor special cradle to secure the oxygen tank.

And here is the fun one.

Should you get into a accident, you could break the neck off the oxygen tank, have it hit you with enough force that the tank will fly and land a block and one half away. Imagine what you look like with a oxygen tank flying thru you.

See what you learn when you work at a large Fire Department?

[Rovin4life]

a bottle of oxygen hooked into the tail pipe will decrease the parts per million of nox and co2.


although its highly illegal and isnt there some sort of video as well.

ive heard some of the tricks but then that was after they got caught for trying them.

[pavel]

Bloody hell, what have I started? Oxygen bottle feeding gas out my tailpipe???? Sounds a bit naughty! Fake OBDII ports????? Gentlemen, my question was not aiming at endangering & subverting society or tricking the emissions test. I ernestly want the engine to run as clean as reasonably possible.

Next time, I'll make sure the cats are hotter and be running fresher wires and plugs for the test. Also, might give her a pretest full Seafoam treatment.