atlthrasher

Just bought a high mileage Accord (201k) and tried to get emissions here in Atlanta...

The car runs great, idles good, no CEL...

Here are the readouts:

25/25 Test
HC ppm -- Passed
Reading -- 30
Allowed -- 132

CO % -- Fail
Reading -- 1.24
Allowed -- 0.73

NO ppm -- Pass
Reading -- 187
Allowed -- 945

RPM
Reading -- 1828
Allowed -- 3000 (max)

CO +CO %
Reading -- 15.6
Allowed -- 6.0 (Min)

Pretty much the same results for the 50/15 test...

Maybe just a dirty air filter (hoping)?

Anyone have any advice on easy things to check myself before taking it to a mechanic...?

Hidenplanvew

Try changing the air filter and Engine coolant temp to ECU not gauge, after that would be 02 sensor. If you know anyone with a snap scanner, hook it up and watch the live Data flow.

v4lu3s

you are running too rich. air filter may help, o2 sensor as well possibly.

Hidenplanvew

CO isnt rich, HC is... CO is Carbon monoxide... Could also be cat issues

holmesnmanny

This could be as simple as a tuneup.

atlthrasher

Thanks for the help! I'm taking it in today to get a tune up.. Hoping it's not the cat since that is pretty pricey...

Fred Demara

Some might call this cheating....I've been close on a few tests, and did the following, and passed.

1) Over-inflate your front tires. You want to do everything you can to reduce the amount of drag or friction on the test surface. I would suggest 46psi - as soon as you are done with the test, put your tires back to normal.

2) Remove your power steering pump belt and ac belt - again, you are trying to give your engine as little friction as possible.

3) Remove your air filter. Remove it right before the test, and put it back in immediately after...driving around town without an air filter will destroy your engine.

4) Change your oil before the test.

5) make sure you let the car warm up - 15-20 minutes of city driving...your cat begins functioning at it's best when it's fully warmed up.

Good luck, let us know how it went

MAD_MIKE

No. CO and O2 are how to tell if an engine is running rich or lean. They are inverse to each other.
If CO is high the engine is running rich.
If O2 is high the engine is running lean.

If CO is high and NOx is low the engine is running rich.

HC is not a good indicator of engine tune. HC can be high if the engine us running too lean or rich. It is also affected by the PCV system, oil contamination, fuel contamination, faulty injectors, etc ,etc ,etc.
I wouldn't even normally look at HC unless a subsystem is suspect.

No. Overinflation, although may reduce rolling resistance on the street, will increase engine load as the tire/wheel will now be taller, affecting the effective final drive ratio.
Make sure the tires are checked when cold and that they are close to the door stickers recommended PSI setting.
Unnecessary and a waste of time. The engine may rev more freely, but this is not going to affect emissions significantly. If it does, there is something else mechanically wrong with the vehicle.
A clean air filter will be fine. Again another silly myth. A clean air filter will not have any restriction on the engine. Let alone on a low speed, low load test.
This is actually helpful if the oil has not been changed in a while.
It can be contaminated with fuel, a change in viscosity may increase load on the engine.
This is also true. The engine needs to be fully warmed up to be at its most efficient. A catalyst does need to be hot so it 'lights off' and works correctly. But do not over heat the catalyst, this can damage it.

atlthrasher if it has been a while since the engine was given a tuneup, I would suggest having one done. The secondary side of the ignition system may just be weak and need some TLC to bring it back up to snuff. However, do NOT have a tuneup done and then bring it directly to have it immediately smogged, more than likely you will fail. A fresh set of plugs will burn hotter and may cause carbon deposits to be burned off, this will affect emissions output. Drive the car around and put ~100miles on it after the tuneup to make sure any deposits are burned off.
-tune up
-fresh oil change
-check PCV valve and system is working
-check coolant levels are correct.

Expect your NOx to rise after fixing the CO problem, do not be concerned. Unless it is excessive/causing an emissions failure.

Hidenplanvew

High NOX is from running to hot in the cylinder creating lean condition...That is why EGR systems introduce exhaust to help "cool Burning" in the cylinders. High HC and low Nox will show a rich condition.

Mike not fighting, Emissions isnt my best area

bandjstone

hey i live here in Chattanooga and i have to get cars thru emissions all the time. go get a bottle of sea foam and have a friend help you suck it thru the intake manifold. i use the power brake booster hose.that goes in to the intake manifold. have your helper maintain the rpms to 2000 and slowley pour the seafoam in the hose it will start to smoke out the tail pipe. but doing this cleans out all the carbon and cleans the cat and the o2 sensors, as well as the valves. i havent had one that didnt pass after doing this good luck.

v4lu3s

high HC is a poor indicator of rich or lean but it is a good indicator of catalytic converter health. CO is a much more precise indicator of AFR. the CO% reading of 1.24 indicates AFR of 14.25:1 and the 0.73 indicates a target of 14.21:1 or leaner. feel free to read wikipedia's entry on air-fuel ratio as it explains the chemistry and shows the equations.


Posted from Honda-tech.com App for Android

Hidenplanvew

HC is unburnt Fuel particals tho

doctorbee

http://www.smogtips.com/failed-high-...onoxide-CO.cfm

Fred Demara

No offense Mike, you're wrong on a few of these points.

1) Completely incorrect. Over inflating doesn't increase diameter significantly, but it does reduce rolling friction by about 3%...3% isn't, but every bit helps. You can learn the basics of rolling resistance here: http://en.wikipedia.org/wiki/Rolling_resistance

2) Totally wrong. Removing your air filter can increase HP by 3-5%. Your engine is a huge air pump...removing any restriction from the air intake increases HP. Some performance air filters can increase hp by 4%, removing it all together makes a big difference..very basic stuff, you can learn more about it here: http://www.knfilters.com/faq.htm#2

3) Any belts (ac/power steering belts) produce drag, this is why so many companies make underdrive/lightweight pullies. Some lightweight pullies can add 10hp..again, removing the belt altogether greatly reduces drag, and increases HP. Here is a helpful site for you: http://www.marchperf.com/tiptricks/underdrive2.html

A freely revving engine, with less drag and more HP, is going to work less hard during the test, increasing your odds of passing. I first heard about several of the above from an automotive expert by the name of "Pat Goss" who had a radio show about 30 years ago...By doing the above, it's estimated you can "free up" roughly 20hp...that's a HUGE amount for a smog test.

doctorbee

although you may be correct,a stock engine should not need mods to pass emissions. Air filter maybe dirty but check the other common causes of running rich

MAD_MIKE

Ever notice anytime someone says 'no offense' they try to be antagonistic?
Uh yeah, I said that rolling resistance would be decreased, but engine load would be increased as the effective final drive ratio would be slightly altered.
I never said a significant amount, just that it would.
Totally wrong?
Your basing this with K&Ns 'FAQ'?
HAH!
When we start doing emissions testing at peak torque and horsepower rpms then what you are saying might have some relevance to an emissions test. Maybe. Actually no, since the stock system was never tested/certified using K&Ns super duper intake tract oilers.
AH, I see you have been catching up on last years emissions article in Import Tuner.
Yes, they do have parasitic drag but none of these will affect the normal operation the engines emission systems. Honda engineers were smart enough to take these 'power sapping' accessories into account.


Pulling off belts, removing air filters, and filling tires with helium is not going to get the car to pass smog.

It has a high CO%, it is running rich. It more than likely just needs a basic tuneup.

No underdrive pulleys.
No conversion to manual steering.
No fart can mufflers.
No ugly manish import model needed.

Even the horny photographer wants nothing to do with her.

Here is an unbiased technical pdf on emissions analysis, rather than links to self promotion or a paid talking head.

Toyota Emission Analysis

HC may be an indication of unburnt fuel. HC can be an indicator of oil, which is also a hydrocarbon.
HC emissions are not a very good indicator of actual engine tune.
It is on a curve.
HC can be high if the engine is running rich.
HC can be high if the engine is running lean.
All a high HC may indicate is that there is an incomplete burn in the combustion chamber. But that can happen if there is too much fuel, or if there is too much air. It can also be affected if the PCV or EVAP system is not properly working. It's good at fine tuning an issue, but not the definite indicator.

Where as CO and O2 are both on slopes.
CO will be high when the engine is running rich. CO will be low when the engine is running lean.
O2 will be high when the engine is running lean. O2 will be low when the engine is running rich.

holmesnmanny

Ya, all an undersized pulley will do is give you slightly more power if you're lucky.

That would be like putting someone at the back of the car and asking them to help push the car. It's not gonna do anything for emissions it's just gonna give you a small push.

Fred Demara

How about a good ole fashioned friendly bet? 100 bucks. I'll take my 98 Odyssey to a local dyno, remove the air filter, ps/ac belts and over inflate the tires. If I don't make at least 10hp at the wheels, you win.

Mike, if you are close on a rolling smog test, 10hp at the wheels might mean the difference between failing and passing. You might not like the facts, but thems is the facts, regardless.

holmesnmanny

Nobody said anything about not making more horsepower. This thread is about smog testing.

Fred Demara

The rolling test requires your engine to produce a specific amount of work. If you increase (or free up) the horsepower at the wheels, your engine is burning less gas to produce the same amount of work. Less gas produces less emissions. The two are directly related.

I'm pretty sure I have an old copy of an emission I failed, then passed just by over inflating the tires and removing the ps belt. The bottom line is, doing the above might help you pass your smog test.

holmesnmanny

They are not related when it comes to electronic fuel injection because the ecu is just going to compensate for less gas being introduced by lengthening the PW.

Fred Demara

On a "plug in" test (non rolling - usually 96 and up) you would be correct. The 96 and up test is not an emissions test, but rather a diagnostic test of your system over the last 150miles (at least, that is what it is in my state). On a 95 and under, and any state that still requires a rolling style dyno/tailpipe test, you are incorrect. Your emissions numbers will be lower straight across the board. Less fuel intake for the same amount of work = less emissions. The only numbers that count on a rolling test are the numbers coming out of your tailpipe, and your ecu only knows that it is delivering less gas to produce the same amount of work - less gas for the same amount of work is less emissions. Very basic stuff.

I had a 95 honda that failed emissions. I inflated the tires, removed the ps belt, gained hp, and produced less emissions, and passed less than 24 hours later....if I can find the file for it, I will post a picture of the emissons test.

If you are close on a rolling smog test, (electronic fuel injection or not) if you produce more hp to create the same amount of work, you could pass the test. It's been done.

FaLKoN240

Did anything come of this? I'm trying to lower my CO on my Accord.